Refactor initAdapter

app/src/main/java/com/h/pixeldroid/posts/feeds/CommonFeedFragmentUtils.kt

@@ -2,25 +2,32 @@ package com.h.pixeldroid.posts.feeds
 
 import android.view.LayoutInflater
 import android.view.ViewGroup
+import android.widget.ProgressBar
+import androidx.constraintlayout.motion.widget.MotionLayout
 import androidx.core.view.isVisible
 import androidx.core.view.size
 import androidx.paging.LoadState
 import androidx.paging.LoadStateAdapter
 import androidx.paging.PagingDataAdapter
 import androidx.recyclerview.widget.RecyclerView
+import androidx.swiperefreshlayout.widget.SwipeRefreshLayout
 import com.h.pixeldroid.R
-import com.h.pixeldroid.databinding.FragmentFeedBinding
+import com.h.pixeldroid.databinding.ErrorLayoutBinding
 import com.h.pixeldroid.databinding.LoadStateFooterViewItemBinding
 
 /**
  * Shows or hides the error in the different FeedFragments
  */
-private fun showError(errorText: String, show: Boolean = true, binding: FragmentFeedBinding){
-    if(show){
-        binding.motionLayout.transitionToEnd()
-        binding.errorLayout.errorText.text = errorText
-    } else if(binding.motionLayout.progress == 1F){
-        binding.motionLayout.transitionToStart()
+private fun showError(
+        errorText: String, show: Boolean = true,
+        motionLayout: MotionLayout,
+        errorLayout: ErrorLayoutBinding){
+
+    if(show) {
+        motionLayout.transitionToEnd()
+        errorLayout.errorText.text = errorText
+    } else if(motionLayout.progress == 1F) {
+        motionLayout.transitionToStart()
     }
 }
 
@@ -29,28 +36,32 @@ private fun showError(errorText: String, show: Boolean = true, binding: Fragment
  *
  * Makes the UI respond to various [LoadState]s, including errors when an error message is shown.
  */
-internal fun <T: Any> initAdapter(binding: FragmentFeedBinding, adapter: PagingDataAdapter<T, RecyclerView.ViewHolder>) {
-    binding.list.adapter = adapter.withLoadStateFooter(
+internal fun <T: Any> initAdapter(
+    progressBar: ProgressBar, swipeRefreshLayout: SwipeRefreshLayout,
+    recyclerView: RecyclerView, motionLayout: MotionLayout, errorLayout: ErrorLayoutBinding,
+    adapter: PagingDataAdapter<T, RecyclerView.ViewHolder>) {
+
+    recyclerView.adapter = adapter.withLoadStateFooter(
         footer = ReposLoadStateAdapter { adapter.retry() }
     )
 
     adapter.addLoadStateListener { loadState ->
 
-        if(!binding.progressBar.isVisible && binding.swipeRefreshLayout.isRefreshing) {
+        if(!progressBar.isVisible && swipeRefreshLayout.isRefreshing) {
             // Stop loading spinner when loading is done
-            binding.swipeRefreshLayout.isRefreshing = loadState.refresh is LoadState.Loading
+            swipeRefreshLayout.isRefreshing = loadState.refresh is LoadState.Loading
         } else {
             // ProgressBar should stop showing as soon as the source stops loading ("source"
             // meaning the database, so don't wait on the network)
             val sourceLoading = loadState.source.refresh is LoadState.Loading
-            if(!sourceLoading && binding.list.size > 0){
-                binding.list.isVisible = true
-                binding.progressBar.isVisible = false
-            } else if(binding.list.size ==  0
+            if(!sourceLoading && recyclerView.size > 0){
+                recyclerView.isVisible = true
+                progressBar.isVisible = false
+            } else if(recyclerView.size ==  0
                     && loadState.append is LoadState.NotLoading
                     && loadState.append.endOfPaginationReached){
-                binding.progressBar.isVisible = false
-                showError(binding = binding, errorText = "Nothing to see here :(")
+                progressBar.isVisible = false
+                showError(motionLayout = motionLayout, errorLayout = errorLayout, errorText = "Nothing to see here :(")
             }
         }
 
@@ -63,13 +74,15 @@ internal fun <T: Any> initAdapter(binding: FragmentFeedBinding, adapter: PagingD
             ?: loadState.prepend as? LoadState.Error
             ?: loadState.refresh as? LoadState.Error
         errorState?.let {
-            showError(binding = binding, errorText = it.error.toString())
+            showError(motionLayout = motionLayout, errorLayout = errorLayout, errorText = it.error.toString())
+        }
+        if(errorState == null) {
+            showError(motionLayout = motionLayout, errorLayout = errorLayout, show = false, errorText = "")
         }
-        if (errorState == null) showError(binding = binding, show = false, errorText = "")
     }
-
 }
 
+
 /**
  * Adapter to the show the a [RecyclerView] item for a [LoadState], with a callback to retry if
  * the retry button is pressed.

app/src/main/java/com/h/pixeldroid/posts/feeds/cachedFeeds/CachedFeedFragment.kt

@@ -70,7 +70,8 @@ open class CachedFeedFragment<T: FeedContentDatabase> : BaseFragment() {
 
         binding = FragmentFeedBinding.inflate(layoutInflater)
 
-        initAdapter(binding, adapter)
+        initAdapter(binding.progressBar, binding.swipeRefreshLayout,
+            binding.list, binding.motionLayout, binding.errorLayout, adapter)
 
         //binding.progressBar.visibility = View.GONE
         binding.swipeRefreshLayout.setOnRefreshListener {

app/src/main/java/com/h/pixeldroid/posts/feeds/uncachedFeeds/UncachedFeedFragment.kt

@@ -67,7 +67,8 @@ open class UncachedFeedFragment<T: FeedContent> : BaseFragment() {
 
         binding = FragmentFeedBinding.inflate(layoutInflater)
 
-        initAdapter(binding, adapter)
+        initAdapter(binding.progressBar, binding.swipeRefreshLayout, binding.list,
+            binding.motionLayout, binding.errorLayout, adapter)
 
         binding.swipeRefreshLayout.setOnRefreshListener {
             //It shouldn't be necessary to also retry() in addition to refresh(),

app/src/main/java/com/h/pixeldroid/posts/feeds/uncachedFeeds/profile/ProfilePagingSource.kt

@@ -33,8 +33,5 @@ class ProfilePagingSource(
         }
     }
 
-    override fun getRefreshKey(state: PagingState<String, Status>): String? =
-        state.anchorPosition?.run {
-            state.closestItemToPosition(this)?.id
-        }
+    override fun getRefreshKey(state: PagingState<String, Status>): String? = null
 }

app/src/main/java/com/h/pixeldroid/profile/ProfileActivity.kt

@@ -9,8 +9,6 @@ import android.view.ViewGroup
 import android.widget.*
 import androidx.appcompat.content.res.AppCompatResources
 import androidx.core.content.ContextCompat
-import androidx.core.view.isVisible
-import androidx.core.view.size
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.lifecycleScope
@@ -24,7 +22,7 @@ import com.h.pixeldroid.R
 import com.h.pixeldroid.databinding.ActivityProfileBinding
 import com.h.pixeldroid.databinding.FragmentProfilePostsBinding
 import com.h.pixeldroid.posts.PostActivity
-import com.h.pixeldroid.posts.feeds.ReposLoadStateAdapter
+import com.h.pixeldroid.posts.feeds.initAdapter
 import com.h.pixeldroid.posts.feeds.uncachedFeeds.FeedViewModel
 import com.h.pixeldroid.posts.feeds.uncachedFeeds.UncachedContentRepository
 import com.h.pixeldroid.posts.feeds.uncachedFeeds.profile.ProfileContentRepository
@@ -88,14 +86,13 @@ class ProfileActivity : BaseActivity() {
         ).get(FeedViewModel::class.java) as FeedViewModel<Status>
 
         profileAdapter = ProfilePostsAdapter()
-        initAdapter(binding, profileAdapter)
+        initAdapter(binding.profileProgressBar, binding.profileRefreshLayout,
+            binding.profilePostsRecyclerView, binding.motionLayout, binding.profileErrorLayout,
+            profileAdapter)
 
         binding.profilePostsRecyclerView.layoutManager = GridLayoutManager(this, 3)
 
         binding.profileRefreshLayout.setOnRefreshListener {
-            //It shouldn't be necessary to also retry() in addition to refresh(),
-            //but if we don't do this, reloads after an error fail immediately...
-            profileAdapter.retry()
             profileAdapter.refresh()
         }
 
@@ -139,52 +136,6 @@ class ProfileActivity : BaseActivity() {
         binding.profileRefreshLayout.isRefreshing = false
     }
 
-    /**
-     * Initialises the [RecyclerView] adapter for the different FeedFragments.
-     *
-     * Makes the UI respond to various [LoadState]s, including errors when an error message is shown.
-     */
-    internal fun <T: Any> initAdapter(binding: ActivityProfileBinding, adapter: PagingDataAdapter<T, RecyclerView.ViewHolder>) {
-        binding.profilePostsRecyclerView.adapter = adapter.withLoadStateFooter(
-                footer = ReposLoadStateAdapter { adapter.retry() }
-        )
-
-        adapter.addLoadStateListener { loadState ->
-
-            if(!binding.profileProgressBar.isVisible && binding.profileRefreshLayout.isRefreshing) {
-                // Stop loading spinner when loading is done
-                binding.profileRefreshLayout.isRefreshing = loadState.refresh is LoadState.Loading
-            } else {
-                // ProgressBar should stop showing as soon as the source stops loading ("source"
-                // meaning the database, so don't wait on the network)
-                val sourceLoading = loadState.source.refresh is LoadState.Loading
-                if(!sourceLoading && binding.profilePostsRecyclerView.size > 0){
-                    binding.profilePostsRecyclerView.isVisible = true
-                    binding.profileProgressBar.isVisible = false
-                } else if(binding.profilePostsRecyclerView.size ==  0
-                        && loadState.append is LoadState.NotLoading
-                        && loadState.append.endOfPaginationReached){
-                    binding.profileProgressBar.isVisible = false
-                    showError(errorText = "Nothing to see here :(")
-                }
-            }
-
-
-            // Toast on any error, regardless of whether it came from RemoteMediator or PagingSource
-            val errorState = loadState.source.append as? LoadState.Error
-                    ?: loadState.source.prepend as? LoadState.Error
-                    ?: loadState.source.refresh as? LoadState.Error
-                    ?: loadState.append as? LoadState.Error
-                    ?: loadState.prepend as? LoadState.Error
-                    ?: loadState.refresh as? LoadState.Error
-            errorState?.let {
-                showError(errorText = it.error.toString())
-            }
-            if (errorState == null) showError(show = false, errorText = "")
-        }
-
-    }
-
     override fun onSupportNavigateUp(): Boolean {
         onBackPressed()
         return true

app/src/main/res/layout/activity_profile.xml

@@ -143,6 +143,7 @@
             tools:visibility="visible">
 
             <include
+                android:id="@+id/profileErrorLayout"
                 layout="@layout/error_layout"
                 tools:layout_editor_absoluteX="50dp" />