Moves loading of accounts, notifications, and statuses to use link headers. Also remedies an issue where duplicate calls for the same chunk of items in a list can occur.

app/src/main/java/com/keylesspalace/tusky/adapter/AccountAdapter.java

@@ -21,12 +21,16 @@ import android.support.v7.widget.RecyclerView;
 import com.keylesspalace.tusky.entity.Account;
 import com.keylesspalace.tusky.interfaces.AccountActionListener;
 
+import java.text.ParseException;
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
 
 public abstract class AccountAdapter extends RecyclerView.Adapter {
     List<Account> accountList;
     AccountActionListener accountActionListener;
+    private String topId;
+    private String bottomId;
 
     AccountAdapter(AccountActionListener accountActionListener) {
         super();
@@ -39,12 +43,20 @@ public abstract class AccountAdapter extends RecyclerView.Adapter {
         return accountList.size() + 1;
     }
 
-    public void update(List<Account> newAccounts) {
+    public void update(@Nullable List<Account> newAccounts, @Nullable String fromId,
+            @Nullable String uptoId) {
         if (newAccounts == null || newAccounts.isEmpty()) {
             return;
         }
+        if (fromId != null) {
+            bottomId = fromId;
+        }
+        if (uptoId != null) {
+            topId = uptoId;
+        }
         if (accountList.isEmpty()) {
-            accountList = newAccounts;
+            // This construction removes duplicates.
+            accountList = new ArrayList<>(new HashSet<>(newAccounts));
         } else {
             int index = accountList.indexOf(newAccounts.get(newAccounts.size() - 1));
             for (int i = 0; i < index; i++) {
@@ -60,11 +72,26 @@ public abstract class AccountAdapter extends RecyclerView.Adapter {
         notifyDataSetChanged();
     }
 
-    public void addItems(List<Account> newAccounts) {
+    public void addItems(List<Account> newAccounts, @Nullable String fromId) {
+        if (fromId != null) {
+            bottomId = fromId;
+        }
         int end = accountList.size();
+        Account last = accountList.get(end - 1);
+        if (last != null && !findAccount(accountList, last.id)) {
             accountList.addAll(newAccounts);
             notifyItemRangeInserted(end, newAccounts.size());
         }
+    }
+
+    private static boolean findAccount(List<Account> accounts, String id) {
+        for (Account account : accounts) {
+            if (account.id.equals(id)) {
+                return true;
+            }
+        }
+        return false;
+    }
 
     @Nullable
     public Account removeItem(int position) {
@@ -84,10 +111,21 @@ public abstract class AccountAdapter extends RecyclerView.Adapter {
         notifyItemInserted(position);
     }
 
+    @Nullable
     public Account getItem(int position) {
         if (position >= 0 && position < accountList.size()) {
             return accountList.get(position);
         }
         return null;
     }
+
+    @Nullable
+    public String getBottomId() {
+        return bottomId;
+    }
+
+    @Nullable
+    public String getTopId() {
+        return topId;
+    }
 }

app/src/main/java/com/keylesspalace/tusky/adapter/NotificationsAdapter.java

@@ -37,6 +37,7 @@ import com.keylesspalace.tusky.interfaces.StatusActionListener;
 import com.squareup.picasso.Picasso;
 
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
 
 public class NotificationsAdapter extends RecyclerView.Adapter implements AdapterItemRemover {
@@ -56,6 +57,8 @@ public class NotificationsAdapter extends RecyclerView.Adapter implements Adapte
     private NotificationActionListener notificationActionListener;
     private FooterState footerState = FooterState.END;
     private boolean mediaPreviewEnabled;
+    private String bottomId;
+    private String topId;
 
     public NotificationsAdapter(StatusActionListener statusListener,
             NotificationActionListener notificationActionListener) {
@@ -186,19 +189,28 @@ public class NotificationsAdapter extends RecyclerView.Adapter implements Adapte
         }
     }
 
-    public @Nullable Notification getItem(int position) {
+    @Nullable
+    public Notification getItem(int position) {
         if (position >= 0 && position < notifications.size()) {
             return notifications.get(position);
         }
         return null;
     }
 
-    public void update(List<Notification> newNotifications) {
+    public void update(@Nullable List<Notification> newNotifications, @Nullable String fromId,
+            @Nullable String uptoId) {
         if (newNotifications == null || newNotifications.isEmpty()) {
             return;
         }
+        if (fromId != null) {
+            bottomId = fromId;
+        }
+        if (uptoId != null) {
+            topId = uptoId;
+        }
         if (notifications.isEmpty()) {
-            notifications = newNotifications;
+            // This construction removes duplicates.
+            notifications = new ArrayList<>(new HashSet<>(newNotifications));
         } else {
             int index = notifications.indexOf(newNotifications.get(newNotifications.size() - 1));
             for (int i = 0; i < index; i++) {
@@ -214,10 +226,25 @@ public class NotificationsAdapter extends RecyclerView.Adapter implements Adapte
         notifyDataSetChanged();
     }
 
-    public void addItems(List<Notification> new_notifications) {
+    public void addItems(List<Notification> newNotifications, @Nullable String fromId) {
+        if (fromId != null) {
+            bottomId = fromId;
+        }
         int end = notifications.size();
-        notifications.addAll(new_notifications);
+        Notification last = notifications.get(end - 1);
-        notifyItemRangeInserted(end, new_notifications.size());
+        if (last != null && !findNotification(notifications, last.id)) {
+            notifications.addAll(newNotifications);
+            notifyItemRangeInserted(end, newNotifications.size());
+        }
+    }
+
+    private static boolean findNotification(List<Notification> notifications, String id) {
+        for (Notification notification : notifications) {
+            if (notification.id.equals(id)) {
+                return true;
+            }
+        }
+        return false;
     }
 
     public void clear() {
@@ -233,6 +260,16 @@ public class NotificationsAdapter extends RecyclerView.Adapter implements Adapte
         }
     }
 
+    @Nullable
+    public String getBottomId() {
+        return bottomId;
+    }
+
+    @Nullable
+    public String getTopId() {
+        return topId;
+    }
+
     public void setMediaPreviewEnabled(boolean enabled) {
         mediaPreviewEnabled = enabled;
     }

app/src/main/java/com/keylesspalace/tusky/adapter/TimelineAdapter.java

@@ -27,6 +27,7 @@ import com.keylesspalace.tusky.interfaces.StatusActionListener;
 import com.keylesspalace.tusky.entity.Status;
 
 import java.util.ArrayList;
+import java.util.HashSet;
 import java.util.List;
 
 public class TimelineAdapter extends RecyclerView.Adapter implements AdapterItemRemover {
@@ -43,6 +44,8 @@ public class TimelineAdapter extends RecyclerView.Adapter implements AdapterItem
     private StatusActionListener statusListener;
     private FooterState footerState = FooterState.END;
     private boolean mediaPreviewEnabled;
+    private String topId;
+    private String bottomId;
 
     public TimelineAdapter(StatusActionListener statusListener) {
         super();
@@ -126,12 +129,20 @@ public class TimelineAdapter extends RecyclerView.Adapter implements AdapterItem
         }
     }
 
-    public void update(List<Status> newStatuses) {
+    public void update(@Nullable List<Status> newStatuses, @Nullable String fromId,
+            @Nullable String uptoId) {
         if (newStatuses == null || newStatuses.isEmpty()) {
             return;
         }
+        if (fromId != null) {
+            bottomId = fromId;
+        }
+        if (uptoId != null) {
+            topId = uptoId;
+        }
         if (statuses.isEmpty()) {
-            statuses = newStatuses;
+            // This construction removes duplicates.
+            statuses = new ArrayList<>(new HashSet<>(newStatuses));
         } else {
             int index = statuses.indexOf(newStatuses.get(newStatuses.size() - 1));
             for (int i = 0; i < index; i++) {
@@ -147,11 +158,26 @@ public class TimelineAdapter extends RecyclerView.Adapter implements AdapterItem
         notifyDataSetChanged();
     }
 
-    public void addItems(List<Status> newStatuses) {
+    public void addItems(List<Status> newStatuses, @Nullable String fromId) {
+        if (fromId != null) {
+            bottomId = fromId;
+        }
         int end = statuses.size();
+        Status last = statuses.get(end - 1);
+        if (last != null && !findStatus(statuses, last.id)) {
             statuses.addAll(newStatuses);
             notifyItemRangeInserted(end, newStatuses.size());
         }
+    }
+
+    private static boolean findStatus(List<Status> statuses, String id) {
+        for (Status status : statuses) {
+            if (status.id.equals(id)) {
+                return true;
+            }
+        }
+        return false;
+    }
 
     public void clear() {
         statuses.clear();
@@ -177,4 +203,14 @@ public class TimelineAdapter extends RecyclerView.Adapter implements AdapterItem
     public void setMediaPreviewEnabled(boolean enabled) {
         mediaPreviewEnabled = enabled;
     }
+
+    @Nullable
+    public String getBottomId() {
+        return bottomId;
+    }
+
+    @Nullable
+    public String getTopId() {
+        return topId;
+    }
 }

app/src/main/java/com/keylesspalace/tusky/fragment/AccountListFragment.java

@@ -43,6 +43,7 @@ import com.keylesspalace.tusky.entity.Relationship;
 import com.keylesspalace.tusky.interfaces.AccountActionListener;
 import com.keylesspalace.tusky.network.MastodonApi;
 import com.keylesspalace.tusky.R;
+import com.keylesspalace.tusky.util.HttpHeaderLink;
 import com.keylesspalace.tusky.util.ThemeUtils;
 import com.keylesspalace.tusky.view.EndlessOnScrollListener;
 
@@ -71,6 +72,10 @@ public class AccountListFragment extends BaseFragment implements AccountActionLi
     private AccountAdapter adapter;
     private TabLayout.OnTabSelectedListener onTabSelectedListener;
     private MastodonApi api;
+    private boolean bottomLoading;
+    private int bottomFetches;
+    private boolean topLoading;
+    private int topFetches;
 
     public static AccountListFragment newInstance(Type type) {
         Bundle arguments = new Bundle();
@@ -160,13 +165,7 @@ public class AccountListFragment extends BaseFragment implements AccountActionLi
         scrollListener = new EndlessOnScrollListener(layoutManager) {
             @Override
             public void onLoadMore(int page, int totalItemsCount, RecyclerView view) {
-                AccountAdapter adapter = (AccountAdapter) view.getAdapter();
+                AccountListFragment.this.onLoadMore(view);
-                Account account = adapter.getItem(adapter.getItemCount() - 2);
-                if (account != null) {
-                    fetchAccounts(account.id, null);
-                } else {
-                    fetchAccounts();
-                }
             }
         };
         recyclerView.addOnScrollListener(scrollListener);
@@ -181,78 +180,6 @@ public class AccountListFragment extends BaseFragment implements AccountActionLi
         super.onDestroyView();
     }
 
-    private void fetchAccounts(final String fromId, String uptoId) {
-        Callback<List<Account>> cb = new Callback<List<Account>>() {
-            @Override
-            public void onResponse(Call<List<Account>> call, Response<List<Account>> response) {
-                if (response.isSuccessful()) {
-                    onFetchAccountsSuccess(response.body(), fromId);
-                } else {
-                    onFetchAccountsFailure(new Exception(response.message()));
-                }
-            }
-
-            @Override
-            public void onFailure(Call<List<Account>> call, Throwable t) {
-                onFetchAccountsFailure((Exception) t);
-            }
-        };
-
-        Call<List<Account>> listCall;
-        switch (type) {
-            default:
-            case FOLLOWS: {
-                listCall = api.accountFollowing(accountId, fromId, uptoId, null);
-                break;
-            }
-            case FOLLOWERS: {
-                listCall = api.accountFollowers(accountId, fromId, uptoId, null);
-                break;
-            }
-            case BLOCKS: {
-                listCall = api.blocks(fromId, uptoId, null);
-                break;
-            }
-            case MUTES: {
-                listCall = api.mutes(fromId, uptoId, null);
-                break;
-            }
-            case FOLLOW_REQUESTS: {
-                listCall = api.followRequests(fromId, uptoId, null);
-                break;
-            }
-        }
-        callList.add(listCall);
-        listCall.enqueue(cb);
-    }
-
-    private void fetchAccounts() {
-        fetchAccounts(null, null);
-    }
-
-    private static boolean findAccount(List<Account> accounts, String id) {
-        for (Account account : accounts) {
-            if (account.id.equals(id)) {
-                return true;
-            }
-        }
-        return false;
-    }
-
-    private void onFetchAccountsSuccess(List<Account> accounts, String fromId) {
-        if (fromId != null) {
-            if (accounts.size() > 0 && !findAccount(accounts, fromId)) {
-                adapter.addItems(accounts);
-            }
-        } else {
-            adapter.update(accounts);
-        }
-    }
-
-    private void onFetchAccountsFailure(Exception exception) {
-        Log.e(TAG, "Fetch failure: " + exception.getMessage());
-    }
-
     @Override
     public void onViewAccount(String id) {
         Intent intent = new Intent(getContext(), AccountActivity.class);
@@ -444,4 +371,126 @@ public class AccountListFragment extends BaseFragment implements AccountActionLi
         layoutManager.scrollToPositionWithOffset(0, 0);
         scrollListener.reset();
     }
+
+    private enum FetchEnd {
+        TOP,
+        BOTTOM
+    }
+
+    private Call<List<Account>> getFetchCallByListType(Type type, String fromId, String uptoId) {
+        switch (type) {
+            default:
+            case FOLLOWS:         return api.accountFollowing(accountId, fromId, uptoId, null);
+            case FOLLOWERS:       return api.accountFollowers(accountId, fromId, uptoId, null);
+            case BLOCKS:          return api.blocks(fromId, uptoId, null);
+            case MUTES:           return api.mutes(fromId, uptoId, null);
+            case FOLLOW_REQUESTS: return api.followRequests(fromId, uptoId, null);
+        }
+    }
+
+    private void fetchAccounts(String fromId, String uptoId, final FetchEnd fetchEnd) {
+        /* If there is a fetch already ongoing, record however many fetches are requested and
+         * fulfill them after it's complete. */
+        if (fetchEnd == FetchEnd.TOP && topLoading) {
+            topFetches++;
+            return;
+        }
+        if (fetchEnd == FetchEnd.BOTTOM && bottomLoading) {
+            bottomFetches++;
+            return;
+        }
+        Callback<List<Account>> cb = new Callback<List<Account>>() {
+            @Override
+            public void onResponse(Call<List<Account>> call, Response<List<Account>> response) {
+                if (response.isSuccessful()) {
+                    String linkHeader = response.headers().get("Link");
+                    onFetchAccountsSuccess(response.body(), linkHeader, fetchEnd);
+                } else {
+                    onFetchAccountsFailure(new Exception(response.message()), fetchEnd);
+                }
+            }
+
+            @Override
+            public void onFailure(Call<List<Account>> call, Throwable t) {
+                onFetchAccountsFailure((Exception) t, fetchEnd);
+            }
+        };
+        Call<List<Account>> listCall = getFetchCallByListType(type, fromId, uptoId);
+        callList.add(listCall);
+        listCall.enqueue(cb);
+    }
+
+    private void onFetchAccountsSuccess(List<Account> accounts, String linkHeader,
+            FetchEnd fetchEnd) {
+        List<HttpHeaderLink> links = HttpHeaderLink.parse(linkHeader);
+        switch (fetchEnd) {
+            case TOP: {
+                HttpHeaderLink previous = HttpHeaderLink.findByRelationType(links, "prev");
+                String uptoId = null;
+                if (previous != null) {
+                    uptoId = previous.uri.getQueryParameter("since_id");
+                }
+                adapter.update(accounts, null, uptoId);
+                break;
+            }
+            case BOTTOM: {
+                HttpHeaderLink next = HttpHeaderLink.findByRelationType(links, "next");
+                String fromId = null;
+                if (next != null) {
+                    fromId = next.uri.getQueryParameter("max_id");
+                }
+                if (adapter.getItemCount() > 1) {
+                    adapter.addItems(accounts, fromId);
+                } else {
+                    /* If this is the first fetch, also save the id from the "previous" link and
+                     * treat this operation as a refresh so the scroll position doesn't get pushed
+                     * down to the end. */
+                    HttpHeaderLink previous = HttpHeaderLink.findByRelationType(links, "prev");
+                    String uptoId = null;
+                    if (previous != null) {
+                        uptoId = previous.uri.getQueryParameter("since_id");
+                    }
+                    adapter.update(accounts, fromId, uptoId);
+                }
+                break;
+            }
+        }
+        fulfillAnyQueuedFetches(fetchEnd);
+    }
+
+    private void onFetchAccountsFailure(Exception exception, FetchEnd fetchEnd) {
+        Log.e(TAG, "Fetch failure: " + exception.getMessage());
+        fulfillAnyQueuedFetches(fetchEnd);
+    }
+
+    private void onRefresh() {
+        fetchAccounts(null, adapter.getTopId(), FetchEnd.TOP);
+    }
+
+    private void onLoadMore(RecyclerView recyclerView) {
+        AccountAdapter adapter = (AccountAdapter) recyclerView.getAdapter();
+        fetchAccounts(adapter.getBottomId(), null, FetchEnd.BOTTOM);
+    }
+
+    private void fulfillAnyQueuedFetches(FetchEnd fetchEnd) {
+        switch (fetchEnd) {
+            case BOTTOM: {
+                bottomLoading = false;
+                if (bottomFetches > 0) {
+                    bottomFetches--;
+                    Log.d(TAG, "extra fetchos " + bottomFetches);
+                    onLoadMore(recyclerView);
+                }
+                break;
+            }
+            case TOP: {
+                topLoading = false;
+                if (topFetches > 0) {
+                    topFetches--;
+                    onRefresh();
+                }
+                break;
+            }
+        }
+    }
 }

app/src/main/java/com/keylesspalace/tusky/fragment/NotificationsFragment.java

@@ -40,6 +40,7 @@ import com.keylesspalace.tusky.entity.Notification;
 import com.keylesspalace.tusky.entity.Status;
 import com.keylesspalace.tusky.interfaces.StatusActionListener;
 import com.keylesspalace.tusky.receiver.TimelineReceiver;
+import com.keylesspalace.tusky.util.HttpHeaderLink;
 import com.keylesspalace.tusky.util.ThemeUtils;
 import com.keylesspalace.tusky.view.EndlessOnScrollListener;
 
@@ -55,15 +56,23 @@ public class NotificationsFragment extends SFragment implements
         SharedPreferences.OnSharedPreferenceChangeListener {
     private static final String TAG = "Notifications"; // logging tag
 
+    private enum FetchEnd {
+        TOP,
+        BOTTOM,
+    }
+
     private SwipeRefreshLayout swipeRefreshLayout;
     private LinearLayoutManager layoutManager;
     private RecyclerView recyclerView;
     private EndlessOnScrollListener scrollListener;
     private NotificationsAdapter adapter;
     private TabLayout.OnTabSelectedListener onTabSelectedListener;
-    private Call<List<Notification>> listCall;
     private boolean hideFab;
     private TimelineReceiver timelineReceiver;
+    private boolean topLoading;
+    private int topFetches;
+    private boolean bottomLoading;
+    private int bottomFetches;
 
     public static NotificationsFragment newInstance() {
         NotificationsFragment fragment = new NotificationsFragment();
@@ -157,27 +166,13 @@ public class NotificationsFragment extends SFragment implements
 
             @Override
             public void onLoadMore(int page, int totalItemsCount, RecyclerView view) {
-                NotificationsAdapter adapter = (NotificationsAdapter) view.getAdapter();
+                NotificationsFragment.this.onLoadMore(view);
-                Notification notification = adapter.getItem(adapter.getItemCount() - 2);
-                if (notification != null) {
-                    sendFetchNotificationsRequest(notification.id, null);
-                } else {
-                    sendFetchNotificationsRequest();
-                }
             }
         };
 
         recyclerView.addOnScrollListener(scrollListener);
     }
 
-    @Override
-    public void onDestroy() {
-        super.onDestroy();
-        if (listCall != null) {
-            listCall.cancel();
-        }
-    }
-
     @Override
     public void onDestroyView() {
         TabLayout tabLayout = (TabLayout) getActivity().findViewById(R.id.tab_layout);
@@ -189,88 +184,9 @@ public class NotificationsFragment extends SFragment implements
         super.onDestroyView();
     }
 
-    private void jumpToTop() {
-        layoutManager.scrollToPosition(0);
-        scrollListener.reset();
-    }
-
-    private void sendFetchNotificationsRequest(final String fromId, String uptoId) {
-        if (fromId != null || adapter.getItemCount() <= 1) {
-            adapter.setFooterState(NotificationsAdapter.FooterState.LOADING);
-        }
-
-        listCall = mastodonAPI.notifications(fromId, uptoId, null);
-
-        listCall.enqueue(new Callback<List<Notification>>() {
-            @Override
-            public void onResponse(Call<List<Notification>> call,
-                    Response<List<Notification>> response) {
-                if (response.isSuccessful()) {
-                    onFetchNotificationsSuccess(response.body(), fromId);
-                } else {
-                    onFetchNotificationsFailure(new Exception(response.message()));
-                }
-            }
-
-            @Override
-            public void onFailure(Call<List<Notification>> call, Throwable t) {
-                onFetchNotificationsFailure((Exception) t);
-            }
-        });
-        callList.add(listCall);
-    }
-
-    private void sendFetchNotificationsRequest() {
-        sendFetchNotificationsRequest(null, null);
-    }
-
-    private static boolean findNotification(List<Notification> notifications, String id) {
-        for (Notification notification : notifications) {
-            if (notification.id.equals(id)) {
-                return true;
-            }
-        }
-        return false;
-    }
-
-    private void onFetchNotificationsSuccess(List<Notification> notifications, String fromId) {
-        if (fromId != null) {
-            if (notifications.size() > 0 && !findNotification(notifications, fromId)) {
-                adapter.addItems(notifications);
-
-                // Set last update id for pull notifications so that we don't get notified
-                // about things we already loaded here
-                SharedPreferences preferences = getActivity()
-                        .getSharedPreferences(getString(R.string.preferences_file_key),
-                                Context.MODE_PRIVATE);
-                SharedPreferences.Editor editor = preferences.edit();
-                editor.putString("lastUpdateId", notifications.get(0).id);
-                editor.apply();
-            }
-        } else {
-            adapter.update(notifications);
-        }
-        if (notifications.size() == 0 && adapter.getItemCount() == 1) {
-            adapter.setFooterState(NotificationsAdapter.FooterState.EMPTY);
-        } else if (fromId != null) {
-            adapter.setFooterState(NotificationsAdapter.FooterState.END);
-        }
-        swipeRefreshLayout.setRefreshing(false);
-    }
-
-    private void onFetchNotificationsFailure(Exception exception) {
-        swipeRefreshLayout.setRefreshing(false);
-        Log.e(TAG, "Fetch failure: " + exception.getMessage());
-    }
-
     @Override
     public void onRefresh() {
-        Notification notification = adapter.getItem(0);
+        sendFetchNotificationsRequest(null, adapter.getTopId(), FetchEnd.TOP);
-        if (notification != null) {
-            sendFetchNotificationsRequest(null, notification.id);
-        } else {
-            sendFetchNotificationsRequest();
-        }
     }
 
     @Override
@@ -334,8 +250,133 @@ public class NotificationsFragment extends SFragment implements
         }
     }
 
+    private void onLoadMore(RecyclerView view) {
+        NotificationsAdapter adapter = (NotificationsAdapter) view.getAdapter();
+        sendFetchNotificationsRequest(adapter.getBottomId(), null, FetchEnd.BOTTOM);
+    }
+
+    private void jumpToTop() {
+        layoutManager.scrollToPosition(0);
+        scrollListener.reset();
+    }
+
+    private void sendFetchNotificationsRequest(String fromId, String uptoId,
+            final FetchEnd fetchEnd) {
+        /* If there is a fetch already ongoing, record however many fetches are requested and
+         * fulfill them after it's complete. */
+        if (fetchEnd == FetchEnd.TOP && topLoading) {
+            topFetches++;
+            return;
+        }
+        if (fetchEnd == FetchEnd.BOTTOM && bottomLoading) {
+            bottomFetches++;
+            return;
+        }
+
+        if (fromId != null || adapter.getItemCount() <= 1) {
+            adapter.setFooterState(NotificationsAdapter.FooterState.LOADING);
+        }
+
+        Call<List<Notification>> call = mastodonApi.notifications(fromId, uptoId, null);
+
+        call.enqueue(new Callback<List<Notification>>() {
+            @Override
+            public void onResponse(Call<List<Notification>> call,
+                    Response<List<Notification>> response) {
+                if (response.isSuccessful()) {
+                    String linkHeader = response.headers().get("Link");
+                    onFetchNotificationsSuccess(response.body(), linkHeader, fetchEnd);
+                } else {
+                    onFetchNotificationsFailure(new Exception(response.message()), fetchEnd);
+                }
+            }
+
+            @Override
+            public void onFailure(Call<List<Notification>> call, Throwable t) {
+                onFetchNotificationsFailure((Exception) t, fetchEnd);
+            }
+        });
+        callList.add(call);
+    }
+
+    private void onFetchNotificationsSuccess(List<Notification> notifications, String linkHeader,
+            FetchEnd fetchEnd) {
+        List<HttpHeaderLink> links = HttpHeaderLink.parse(linkHeader);
+        switch (fetchEnd) {
+            case TOP: {
+                HttpHeaderLink previous = HttpHeaderLink.findByRelationType(links, "prev");
+                String uptoId = null;
+                if (previous != null) {
+                    uptoId = previous.uri.getQueryParameter("since_id");
+                }
+                adapter.update(notifications, null, uptoId);
+                break;
+            }
+            case BOTTOM: {
+                HttpHeaderLink next = HttpHeaderLink.findByRelationType(links, "next");
+                String fromId = null;
+                if (next != null) {
+                    fromId = next.uri.getQueryParameter("max_id");
+                }
+                if (adapter.getItemCount() > 1) {
+                    adapter.addItems(notifications, fromId);
+                } else {
+                    /* If this is the first fetch, also save the id from the "previous" link and
+                     * treat this operation as a refresh so the scroll position doesn't get pushed
+                     * down to the end. */
+                    HttpHeaderLink previous = HttpHeaderLink.findByRelationType(links, "prev");
+                    String uptoId = null;
+                    if (previous != null) {
+                        uptoId = previous.uri.getQueryParameter("since_id");
+                    }
+                    adapter.update(notifications, fromId, uptoId);
+                }
+                /* Set last update id for pull notifications so that we don't get notified
+                 * about things we already loaded here */
+                getPrivatePreferences().edit()
+                        .putString("lastUpdateId", fromId)
+                        .apply();
+                break;
+            }
+        }
+        fulfillAnyQueuedFetches(fetchEnd);
+        if (notifications.size() == 0 && adapter.getItemCount() == 1) {
+            adapter.setFooterState(NotificationsAdapter.FooterState.EMPTY);
+        } else {
+            adapter.setFooterState(NotificationsAdapter.FooterState.END);
+        }
+        swipeRefreshLayout.setRefreshing(false);
+    }
+
+    private void onFetchNotificationsFailure(Exception exception, FetchEnd fetchEnd) {
+        swipeRefreshLayout.setRefreshing(false);
+        Log.e(TAG, "Fetch failure: " + exception.getMessage());
+        fulfillAnyQueuedFetches(fetchEnd);
+    }
+
+    private void fulfillAnyQueuedFetches(FetchEnd fetchEnd) {
+        switch (fetchEnd) {
+            case BOTTOM: {
+                bottomLoading = false;
+                if (bottomFetches > 0) {
+                    bottomFetches--;
+                    onLoadMore(recyclerView);
+                }
+                break;
+            }
+            case TOP: {
+                topLoading = false;
+                if (topFetches > 0) {
+                    topFetches--;
+                    onRefresh();
+                }
+                break;
+            }
+        }
+    }
+
     private void fullyRefresh() {
         adapter.clear();
-        sendFetchNotificationsRequest(null, null);
+        sendFetchNotificationsRequest(null, null, FetchEnd.TOP);
     }
 }

app/src/main/java/com/keylesspalace/tusky/fragment/SFragment.java

@@ -57,10 +57,11 @@ import retrofit2.Response;
  * overlap functionality. So, I'm momentarily leaving it and hopefully working on those will clear
  * up what needs to be where. */
 public abstract class SFragment extends BaseFragment {
+    protected static final int COMPOSE_RESULT = 1;
+
     protected String loggedInAccountId;
     protected String loggedInUsername;
-    protected MastodonApi mastodonAPI;
+    protected MastodonApi mastodonApi;
-    protected static int COMPOSE_RESULT = 1;
 
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
@@ -75,7 +76,13 @@ public abstract class SFragment extends BaseFragment {
     public void onActivityCreated(@Nullable Bundle savedInstanceState) {
         super.onActivityCreated(savedInstanceState);
         BaseActivity activity = (BaseActivity) getActivity();
-        mastodonAPI = activity.mastodonApi;
+        mastodonApi = activity.mastodonApi;
+    }
+
+    @Override
+    public void startActivity(Intent intent) {
+        super.startActivity(intent);
+        getActivity().overridePendingTransition(R.anim.slide_from_right, R.anim.slide_to_left);
     }
 
     protected void reply(Status status) {
@@ -122,9 +129,9 @@ public abstract class SFragment extends BaseFragment {
 
         Call<Status> call;
         if (reblog) {
-            call = mastodonAPI.reblogStatus(id);
+            call = mastodonApi.reblogStatus(id);
         } else {
-            call = mastodonAPI.unreblogStatus(id);
+            call = mastodonApi.unreblogStatus(id);
         }
         call.enqueue(cb);
         callList.add(call);
@@ -154,16 +161,16 @@ public abstract class SFragment extends BaseFragment {
 
         Call<Status> call;
         if (favourite) {
-            call = mastodonAPI.favouriteStatus(id);
+            call = mastodonApi.favouriteStatus(id);
         } else {
-            call = mastodonAPI.unfavouriteStatus(id);
+            call = mastodonApi.unfavouriteStatus(id);
         }
         call.enqueue(cb);
         callList.add(call);
     }
 
     private void mute(String id) {
-        Call<Relationship> call = mastodonAPI.muteAccount(id);
+        Call<Relationship> call = mastodonApi.muteAccount(id);
         call.enqueue(new Callback<Relationship>() {
             @Override
             public void onResponse(Call<Relationship> call, Response<Relationship> response) {}
@@ -179,7 +186,7 @@ public abstract class SFragment extends BaseFragment {
     }
 
     private void block(String id) {
-        Call<Relationship> call = mastodonAPI.blockAccount(id);
+        Call<Relationship> call = mastodonApi.blockAccount(id);
         call.enqueue(new Callback<Relationship>() {
             @Override
             public void onResponse(Call<Relationship> call, retrofit2.Response<Relationship> response) {}
@@ -195,7 +202,7 @@ public abstract class SFragment extends BaseFragment {
     }
 
     private void delete(String id) {
-        Call<ResponseBody> call = mastodonAPI.deleteStatus(id);
+        Call<ResponseBody> call = mastodonApi.deleteStatus(id);
         call.enqueue(new Callback<ResponseBody>() {
             @Override
             public void onResponse(Call<ResponseBody> call, retrofit2.Response<ResponseBody> response) {}
@@ -313,12 +320,6 @@ public abstract class SFragment extends BaseFragment {
         startActivity(intent);
     }
 
-    @Override
-    public void startActivity(Intent intent) {
-        super.startActivity(intent);
-        getActivity().overridePendingTransition(R.anim.slide_from_right, R.anim.slide_to_left);
-    }
-
     protected void openReportPage(String accountId, String accountUsername, String statusId,
             Spanned statusContent) {
         Intent intent = new Intent(getContext(), ReportActivity.class);

app/src/main/java/com/keylesspalace/tusky/fragment/TimelineFragment.java

@@ -38,7 +38,9 @@ import com.keylesspalace.tusky.R;
 import com.keylesspalace.tusky.adapter.TimelineAdapter;
 import com.keylesspalace.tusky.entity.Status;
 import com.keylesspalace.tusky.interfaces.StatusActionListener;
+import com.keylesspalace.tusky.network.MastodonApi;
 import com.keylesspalace.tusky.receiver.TimelineReceiver;
+import com.keylesspalace.tusky.util.HttpHeaderLink;
 import com.keylesspalace.tusky.util.ThemeUtils;
 import com.keylesspalace.tusky.view.EndlessOnScrollListener;
 
@@ -64,6 +66,11 @@ public class TimelineFragment extends SFragment implements
         FAVOURITES
     }
 
+    private enum FetchEnd {
+        TOP,
+        BOTTOM,
+    }
+
     private SwipeRefreshLayout swipeRefreshLayout;
     private TimelineAdapter adapter;
     private Kind kind;
@@ -72,11 +79,14 @@ public class TimelineFragment extends SFragment implements
     private LinearLayoutManager layoutManager;
     private EndlessOnScrollListener scrollListener;
     private TabLayout.OnTabSelectedListener onTabSelectedListener;
-    private SharedPreferences preferences;
     private boolean filterRemoveReplies;
     private boolean filterRemoveReblogs;
     private boolean hideFab;
     private TimelineReceiver timelineReceiver;
+    private boolean topLoading;
+    private int topFetches;
+    private boolean bottomLoading;
+    private int bottomFetches;
 
     public static TimelineFragment newInstance(Kind kind) {
         TimelineFragment fragment = new TimelineFragment();
@@ -198,8 +208,6 @@ public class TimelineFragment extends SFragment implements
             };
         }
         recyclerView.addOnScrollListener(scrollListener);
-
-        preferences = PreferenceManager.getDefaultSharedPreferences(getActivity());
     }
 
     @Override
@@ -212,20 +220,9 @@ public class TimelineFragment extends SFragment implements
         super.onDestroyView();
     }
 
-    @Override
-    public void onResume() {
-        super.onResume();
-        setFiltersFromSettings();
-    }
-
     @Override
     public void onRefresh() {
-        Status status = adapter.getItem(0);
+        sendFetchTimelineRequest(null, adapter.getTopId(), FetchEnd.TOP);
-        if (status != null) {
-            sendFetchTimelineRequest(null, status.id);
-        } else {
-            sendFetchTimelineRequest(null, null);
-        }
     }
 
     @Override
@@ -290,22 +287,35 @@ public class TimelineFragment extends SFragment implements
                 fullyRefresh();
                 break;
             }
+            case "tabFilterHomeReplies": {
+                boolean filter = sharedPreferences.getBoolean("tabFilterHomeReplies", true);
+                boolean oldRemoveReplies = filterRemoveReplies;
+                filterRemoveReplies = kind == Kind.HOME && !filter;
+                if (adapter.getItemCount() > 1 && oldRemoveReplies != filterRemoveReplies) {
+                    fullyRefresh();
+                }
+                break;
+            }
+            case "tabFilterHomeBoosts": {
+                boolean filter = sharedPreferences.getBoolean("tabFilterHomeBoosts", true);
+                boolean oldRemoveReblogs = filterRemoveReblogs;
+                filterRemoveReblogs = kind == Kind.HOME && !filter;
+                if (adapter.getItemCount() > 1 && oldRemoveReblogs != filterRemoveReblogs) {
+                    fullyRefresh();
+                }
+                break;
+            }
         }
     }
 
     private void onLoadMore(RecyclerView view) {
         TimelineAdapter adapter = (TimelineAdapter) view.getAdapter();
-        Status status = adapter.getItem(adapter.getItemCount() - 2);
+        sendFetchTimelineRequest(adapter.getBottomId(), null, FetchEnd.BOTTOM);
-        if (status != null) {
-            sendFetchTimelineRequest(status.id, null);
-        } else {
-            sendFetchTimelineRequest(null, null);
-        }
     }
 
     private void fullyRefresh() {
         adapter.clear();
-        sendFetchTimelineRequest(null, null);
+        sendFetchTimelineRequest(null, null, FetchEnd.TOP);
     }
 
     private boolean jumpToTopAllowed() {
@@ -321,7 +331,33 @@ public class TimelineFragment extends SFragment implements
         scrollListener.reset();
     }
 
-    private void sendFetchTimelineRequest(@Nullable final String fromId, @Nullable String uptoId) {
+    private Call<List<Status>> getFetchCallByTimelineType(Kind kind, String tagOrId, String fromId,
+            String uptoId) {
+        MastodonApi api = mastodonApi;
+        switch (kind) {
+            default:
+            case HOME:             return api.homeTimeline(fromId, uptoId, null);
+            case PUBLIC_FEDERATED: return api.publicTimeline(null, fromId, uptoId, null);
+            case PUBLIC_LOCAL:     return api.publicTimeline(true, fromId, uptoId, null);
+            case TAG:              return api.hashtagTimeline(tagOrId, null, fromId, uptoId, null);
+            case USER:             return api.accountStatuses(tagOrId, fromId, uptoId, null);
+            case FAVOURITES:       return api.favourites(fromId, uptoId, null);
+        }
+    }
+
+    private void sendFetchTimelineRequest(@Nullable String fromId, @Nullable String uptoId,
+            final FetchEnd fetchEnd) {
+        /* If there is a fetch already ongoing, record however many fetches are requested and
+         * fulfill them after it's complete. */
+        if (fetchEnd == FetchEnd.TOP && topLoading) {
+            topFetches++;
+            return;
+        }
+        if (fetchEnd == FetchEnd.BOTTOM && bottomLoading) {
+            bottomFetches++;
+            return;
+        }
+
         if (fromId != null || adapter.getItemCount() <= 1) {
             adapter.setFooterState(TimelineAdapter.FooterState.LOADING);
         }
@@ -330,99 +366,104 @@ public class TimelineFragment extends SFragment implements
             @Override
             public void onResponse(Call<List<Status>> call, Response<List<Status>> response) {
                 if (response.isSuccessful()) {
-                    onFetchTimelineSuccess(response.body(), fromId);
+                    String linkHeader = response.headers().get("Link");
+                    onFetchTimelineSuccess(response.body(), linkHeader, fetchEnd);
                 } else {
-                    onFetchTimelineFailure(new Exception(response.message()));
+                    onFetchTimelineFailure(new Exception(response.message()), fetchEnd);
                 }
             }
 
             @Override
             public void onFailure(Call<List<Status>> call, Throwable t) {
-                onFetchTimelineFailure((Exception) t);
+                onFetchTimelineFailure((Exception) t, fetchEnd);
             }
         };
 
-        Call<List<Status>> listCall;
+        Call<List<Status>> listCall = getFetchCallByTimelineType(kind, hashtagOrId, fromId, uptoId);
-        switch (kind) {
-            default:
-            case HOME: {
-                listCall = mastodonAPI.homeTimeline(fromId, uptoId, null);
-                break;
-            }
-            case PUBLIC_FEDERATED: {
-                listCall = mastodonAPI.publicTimeline(null, fromId, uptoId, null);
-                break;
-            }
-            case PUBLIC_LOCAL: {
-                listCall = mastodonAPI.publicTimeline(true, fromId, uptoId, null);
-                break;
-            }
-            case TAG: {
-                listCall = mastodonAPI.hashtagTimeline(hashtagOrId, null, fromId, uptoId, null);
-                break;
-            }
-            case USER: {
-                listCall = mastodonAPI.accountStatuses(hashtagOrId, fromId, uptoId, null);
-                break;
-            }
-            case FAVOURITES: {
-                listCall = mastodonAPI.favourites(fromId, uptoId, null);
-                break;
-            }
-        }
         callList.add(listCall);
         listCall.enqueue(callback);
     }
 
-    private static boolean findStatus(List<Status> statuses, String id) {
+    public void onFetchTimelineSuccess(List<Status> statuses, String linkHeader,
-        for (Status status : statuses) {
+            FetchEnd fetchEnd) {
-            if (status.id.equals(id)) {
+        filterStatuses(statuses);
-                return true;
+        List<HttpHeaderLink> links = HttpHeaderLink.parse(linkHeader);
+        switch (fetchEnd) {
+            case TOP: {
+                HttpHeaderLink previous = HttpHeaderLink.findByRelationType(links, "prev");
+                String uptoId = null;
+                if (previous != null) {
+                    uptoId = previous.uri.getQueryParameter("since_id");
+                }
+                adapter.update(statuses, null, uptoId);
+                break;
+            }
+            case BOTTOM: {
+                HttpHeaderLink next = HttpHeaderLink.findByRelationType(links, "next");
+                String fromId = null;
+                if (next != null) {
+                    fromId = next.uri.getQueryParameter("max_id");
+                }
+                if (adapter.getItemCount() > 1) {
+                    adapter.addItems(statuses, fromId);
+                } else {
+                    /* If this is the first fetch, also save the id from the "previous" link and
+                     * treat this operation as a refresh so the scroll position doesn't get pushed
+                     * down to the end. */
+                    HttpHeaderLink previous = HttpHeaderLink.findByRelationType(links, "prev");
+                    String uptoId = null;
+                    if (previous != null) {
+                        uptoId = previous.uri.getQueryParameter("since_id");
+                    }
+                    adapter.update(statuses, fromId, uptoId);
+                }
+                break;
+            }
+        }
+        fulfillAnyQueuedFetches(fetchEnd);
+        if (statuses.size() == 0 && adapter.getItemCount() == 1) {
+            adapter.setFooterState(TimelineAdapter.FooterState.EMPTY);
+        } else {
+            adapter.setFooterState(TimelineAdapter.FooterState.END);
+        }
+        swipeRefreshLayout.setRefreshing(false);
+    }
+
+    public void onFetchTimelineFailure(Exception exception, FetchEnd fetchEnd) {
+        swipeRefreshLayout.setRefreshing(false);
+        Log.e(TAG, "Fetch Failure: " + exception.getMessage());
+        fulfillAnyQueuedFetches(fetchEnd);
+    }
+
+    private void fulfillAnyQueuedFetches(FetchEnd fetchEnd) {
+        switch (fetchEnd) {
+            case BOTTOM: {
+                bottomLoading = false;
+                if (bottomFetches > 0) {
+                    bottomFetches--;
+                    onLoadMore(recyclerView);
+                }
+                break;
+            }
+            case TOP: {
+                topLoading = false;
+                if (topFetches > 0) {
+                    topFetches--;
+                    onRefresh();
+                }
+                break;
             }
         }
-        return false;
     }
 
     protected void filterStatuses(List<Status> statuses) {
         Iterator<Status> it = statuses.iterator();
         while (it.hasNext()) {
             Status status = it.next();
-            if ((status.inReplyToId != null && filterRemoveReplies) || (status.reblog != null && filterRemoveReblogs)) {
+            if ((status.inReplyToId != null && filterRemoveReplies)
+                    || (status.reblog != null && filterRemoveReblogs)) {
                 it.remove();
             }
         }
     }
-
-    protected void setFiltersFromSettings() {
-        boolean oldRemoveReplies = filterRemoveReplies;
-        boolean oldRemoveReblogs = filterRemoveReblogs;
-        filterRemoveReplies = (kind == Kind.HOME && !preferences.getBoolean("tabFilterHomeReplies", true));
-        filterRemoveReblogs = (kind == Kind.HOME && !preferences.getBoolean("tabFilterHomeBoosts", true));
-
-        if (adapter.getItemCount() > 1 && (oldRemoveReblogs != filterRemoveReblogs || oldRemoveReplies != filterRemoveReplies)) {
-            fullyRefresh();
-        }
-    }
-
-    public void onFetchTimelineSuccess(List<Status> statuses, String fromId) {
-        filterStatuses(statuses);
-        if (fromId != null) {
-            if (statuses.size() > 0 && !findStatus(statuses, fromId)) {
-                adapter.addItems(statuses);
-            }
-        } else {
-            adapter.update(statuses);
-        }
-        if (statuses.size() == 0 && adapter.getItemCount() == 1) {
-            adapter.setFooterState(TimelineAdapter.FooterState.EMPTY);
-        } else if(fromId != null) {
-            adapter.setFooterState(TimelineAdapter.FooterState.END);
-        }
-        swipeRefreshLayout.setRefreshing(false);
-    }
-
-    public void onFetchTimelineFailure(Exception exception) {
-        swipeRefreshLayout.setRefreshing(false);
-        Log.e(TAG, "Fetch Failure: " + exception.getMessage());
-    }
 }

app/src/main/java/com/keylesspalace/tusky/fragment/ViewThreadFragment.java

@@ -35,10 +35,8 @@ import android.view.ViewGroup;
 
 
 import com.keylesspalace.tusky.adapter.ThreadAdapter;
-import com.keylesspalace.tusky.BaseActivity;
 import com.keylesspalace.tusky.entity.Status;
 import com.keylesspalace.tusky.entity.StatusContext;
-import com.keylesspalace.tusky.network.MastodonApi;
 import com.keylesspalace.tusky.R;
 import com.keylesspalace.tusky.interfaces.StatusActionListener;
 import com.keylesspalace.tusky.receiver.TimelineReceiver;
@@ -56,7 +54,6 @@ public class ViewThreadFragment extends SFragment implements
     private SwipeRefreshLayout swipeRefreshLayout;
     private RecyclerView recyclerView;
     private ThreadAdapter adapter;
-    private MastodonApi mastodonApi;
     private String thisThreadsStatusId;
     private TimelineReceiver timelineReceiver;
 
@@ -97,7 +94,6 @@ public class ViewThreadFragment extends SFragment implements
         adapter.setMediaPreviewEnabled(mediaPreviewEnabled);
         recyclerView.setAdapter(adapter);
 
-        mastodonApi = null;
         thisThreadsStatusId = null;
 
         timelineReceiver = new TimelineReceiver(adapter, this);
@@ -117,77 +113,10 @@ public class ViewThreadFragment extends SFragment implements
     @Override
     public void onActivityCreated(@Nullable Bundle savedInstanceState) {
         super.onActivityCreated(savedInstanceState);
-
-        /* BaseActivity's MastodonApi object isn't guaranteed to be valid until after its onCreate
-         * is run, so all calls that need it can't be done until here. */
-        mastodonApi = ((BaseActivity) getActivity()).mastodonApi;
-
         thisThreadsStatusId = getArguments().getString("id");
         onRefresh();
     }
 
-    private void sendStatusRequest(final String id) {
-        Call<Status> call = mastodonApi.status(id);
-        call.enqueue(new Callback<Status>() {
-            @Override
-            public void onResponse(Call<Status> call, Response<Status> response) {
-                if (response.isSuccessful()) {
-                    int position = adapter.setStatus(response.body());
-                    recyclerView.scrollToPosition(position);
-                } else {
-                    onThreadRequestFailure(id);
-                }
-            }
-
-            @Override
-            public void onFailure(Call<Status> call, Throwable t) {
-                onThreadRequestFailure(id);
-            }
-        });
-        callList.add(call);
-    }
-
-    private void sendThreadRequest(final String id) {
-        Call<StatusContext> call = mastodonApi.statusContext(id);
-        call.enqueue(new Callback<StatusContext>() {
-            @Override
-            public void onResponse(Call<StatusContext> call, Response<StatusContext> response) {
-                if (response.isSuccessful()) {
-                    swipeRefreshLayout.setRefreshing(false);
-                    StatusContext context = response.body();
-
-                    adapter.setContext(context.ancestors, context.descendants);
-                } else {
-                    onThreadRequestFailure(id);
-                }
-            }
-
-            @Override
-            public void onFailure(Call<StatusContext> call, Throwable t) {
-                onThreadRequestFailure(id);
-            }
-        });
-        callList.add(call);
-    }
-
-    private void onThreadRequestFailure(final String id) {
-        View view = getView();
-        swipeRefreshLayout.setRefreshing(false);
-        if (view != null) {
-            Snackbar.make(view, R.string.error_generic, Snackbar.LENGTH_LONG)
-                    .setAction(R.string.action_retry, new View.OnClickListener() {
-                        @Override
-                        public void onClick(View v) {
-                            sendThreadRequest(id);
-                            sendStatusRequest(id);
-                        }
-                    })
-                    .show();
-        } else {
-            Log.e(TAG, "Couldn't display thread fetch error message");
-        }
-    }
-
     @Override
     public void onRefresh() {
         sendStatusRequest(thisThreadsStatusId);
@@ -238,4 +167,65 @@ public class ViewThreadFragment extends SFragment implements
     public void onViewAccount(String id) {
         super.viewAccount(id);
     }
+
+    private void sendStatusRequest(final String id) {
+        Call<Status> call = mastodonApi.status(id);
+        call.enqueue(new Callback<Status>() {
+            @Override
+            public void onResponse(Call<Status> call, Response<Status> response) {
+                if (response.isSuccessful()) {
+                    int position = adapter.setStatus(response.body());
+                    recyclerView.scrollToPosition(position);
+                } else {
+                    onThreadRequestFailure(id);
+                }
+            }
+
+            @Override
+            public void onFailure(Call<Status> call, Throwable t) {
+                onThreadRequestFailure(id);
+            }
+        });
+        callList.add(call);
+    }
+
+    private void sendThreadRequest(final String id) {
+        Call<StatusContext> call = mastodonApi.statusContext(id);
+        call.enqueue(new Callback<StatusContext>() {
+            @Override
+            public void onResponse(Call<StatusContext> call, Response<StatusContext> response) {
+                if (response.isSuccessful()) {
+                    swipeRefreshLayout.setRefreshing(false);
+                    StatusContext context = response.body();
+                    adapter.setContext(context.ancestors, context.descendants);
+                } else {
+                    onThreadRequestFailure(id);
+                }
+            }
+
+            @Override
+            public void onFailure(Call<StatusContext> call, Throwable t) {
+                onThreadRequestFailure(id);
+            }
+        });
+        callList.add(call);
+    }
+
+    private void onThreadRequestFailure(final String id) {
+        View view = getView();
+        swipeRefreshLayout.setRefreshing(false);
+        if (view != null) {
+            Snackbar.make(view, R.string.error_generic, Snackbar.LENGTH_LONG)
+                    .setAction(R.string.action_retry, new View.OnClickListener() {
+                        @Override
+                        public void onClick(View v) {
+                            sendThreadRequest(id);
+                            sendStatusRequest(id);
+                        }
+                    })
+                    .show();
+        } else {
+            Log.e(TAG, "Couldn't display thread fetch error message");
+        }
+    }
 }

app/src/main/java/com/keylesspalace/tusky/util/HttpHeaderLink.java

@@ -0,0 +1,148 @@
+/* Written in 2017 by Andrew Dawson
+ *
+ * To the extent possible under law, the author(s) have dedicated all copyright and related and
+ * neighboring rights to this software to the public domain worldwide. This software is distributed
+ * without any warranty.
+ *
+ * You should have received a copy of the CC0 Public Domain Dedication along with this software.
+ * If not, see <http://creativecommons.org/publicdomain/zero/1.0/>. */
+
+package com.keylesspalace.tusky.util;
+
+import android.net.Uri;
+import android.support.annotation.Nullable;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class HttpHeaderLink {
+    private static class Parameter {
+        public String name;
+        public String value;
+    }
+
+    private List<Parameter> parameters;
+    public Uri uri;
+
+    private HttpHeaderLink(String uri) {
+        this.uri = Uri.parse(uri);
+        this.parameters = new ArrayList<>();
+    }
+
+    private static int findAny(String s, int fromIndex, char[] set) {
+        for (int i = fromIndex; i < s.length(); i++) {
+            char c = s.charAt(i);
+            for (char member : set) {
+                if (c == member) {
+                    return i;
+                }
+            }
+        }
+        return -1;
+    }
+
+    private static int findEndOfQuotedString(String line, int start) {
+        for (int i = start; i < line.length(); i++) {
+            char c = line.charAt(i);
+            if (c == '\\') {
+                i += 1;
+            } else if (c == '"') {
+                return i;
+            }
+        }
+        return -1;
+    }
+
+    private static class ValueResult {
+        String value;
+        int end;
+
+        ValueResult() {
+            end = -1;
+        }
+
+        void setValue(String value) {
+            value = value.trim();
+            if (!value.isEmpty()) {
+                this.value = value;
+            }
+        }
+    }
+
+    private static ValueResult parseValue(String line, int start) {
+        ValueResult result = new ValueResult();
+        int foundIndex = findAny(line, start, new char[] {';', ',', '"'});
+        if (foundIndex == -1) {
+            result.setValue(line.substring(start));
+            return result;
+        }
+        char c = line.charAt(foundIndex);
+        if (c == ';' || c == ',') {
+            result.end = foundIndex;
+            result.setValue(line.substring(start, foundIndex));
+            return result;
+        } else {
+            int quoteEnd = findEndOfQuotedString(line, foundIndex + 1);
+            if (quoteEnd == -1) {
+                quoteEnd = line.length();
+            }
+            result.end = quoteEnd;
+            result.setValue(line.substring(foundIndex + 1, quoteEnd));
+            return result;
+        }
+    }
+
+    private static int parseParameters(String line, int start, HttpHeaderLink link) {
+        for (int i = start; i < line.length(); i++) {
+            int foundIndex = findAny(line, i, new char[] {'=', ','});
+            if (foundIndex == -1) {
+                return -1;
+            } else if (line.charAt(foundIndex) == ',') {
+                return foundIndex;
+            }
+            Parameter parameter = new Parameter();
+            parameter.name = line.substring(line.indexOf(';', i) + 1, foundIndex).trim();
+            link.parameters.add(parameter);
+            ValueResult result = parseValue(line, foundIndex);
+            parameter.value = result.value;
+            if (result.end == -1) {
+                return -1;
+            } else {
+                i = result.end;
+            }
+        }
+        return -1;
+    }
+
+    public static List<HttpHeaderLink> parse(@Nullable String line) {
+        List<HttpHeaderLink> linkList = new ArrayList<>();
+        if (line != null) {
+            for (int i = 0; i < line.length(); i++) {
+                int uriEnd = line.indexOf('>', i);
+                String uri = line.substring(line.indexOf('<', i) + 1, uriEnd);
+                HttpHeaderLink link = new HttpHeaderLink(uri);
+                linkList.add(link);
+                int parseEnd = parseParameters(line, uriEnd, link);
+                if (parseEnd == -1) {
+                    break;
+                } else {
+                    i = parseEnd;
+                }
+            }
+        }
+        return linkList;
+    }
+
+    @Nullable
+    public static HttpHeaderLink findByRelationType(List<HttpHeaderLink> links,
+            String relationType) {
+        for (HttpHeaderLink link : links) {
+            for (Parameter parameter : link.parameters) {
+                if (parameter.name.equals("rel") && parameter.value.equals(relationType)) {
+                    return link;
+                }
+            }
+        }
+        return null;
+    }
+}

app/src/main/res/values/strings.xml

@@ -115,7 +115,7 @@
     <string name="hint_content_warning">Content warning</string>
     <string name="hint_display_name">Display name</string>
     <string name="hint_note">Bio</string>
-    <string name="hint_search">Search accounts and tags…</string>
+    <string name="hint_search">Search…</string>
 
     <string name="search_no_results">No results</string>