Implement collections

app/src/main/AndroidManifest.xml

@@ -86,6 +86,7 @@
             android:name=".profile.ProfileActivity"
             android:screenOrientation="sensorPortrait"
             tools:ignore="LockedOrientationActivity" />
+        <activity android:name=".profile.CollectionActivity"/>
         <activity
             android:name=".settings.SettingsActivity"
             android:label="@string/title_activity_settings2"

app/src/main/java/org/pixeldroid/app/posts/feeds/uncachedFeeds/profile/CollectionsContentRepository.kt

@@ -0,0 +1,32 @@
+package org.pixeldroid.app.posts.feeds.uncachedFeeds.profile
+
+import androidx.paging.ExperimentalPagingApi
+import androidx.paging.Pager
+import androidx.paging.PagingConfig
+import androidx.paging.PagingData
+import org.pixeldroid.app.posts.feeds.uncachedFeeds.UncachedContentRepository
+import org.pixeldroid.app.utils.api.PixelfedAPI
+import kotlinx.coroutines.flow.Flow
+import org.pixeldroid.app.utils.api.objects.Collection
+import javax.inject.Inject
+
+class CollectionsContentRepository @ExperimentalPagingApi
+@Inject constructor(
+    private val api: PixelfedAPI,
+    private val accountId: String,
+) : UncachedContentRepository<Collection> {
+    override fun getStream(): Flow<PagingData<Collection>> {
+        return Pager(
+            config = PagingConfig(
+                initialLoadSize = NETWORK_PAGE_SIZE,
+                pageSize = NETWORK_PAGE_SIZE),
+            pagingSourceFactory = {
+                CollectionsPagingSource(api, accountId)
+            }
+        ).flow
+    }
+
+    companion object {
+        private const val NETWORK_PAGE_SIZE = 20
+    }
+}

app/src/main/java/org/pixeldroid/app/posts/feeds/uncachedFeeds/profile/CollectionsPagingSource.kt

@@ -0,0 +1,32 @@
+package org.pixeldroid.app.posts.feeds.uncachedFeeds.profile
+
+import androidx.paging.PagingSource
+import androidx.paging.PagingState
+import org.pixeldroid.app.utils.api.PixelfedAPI
+import org.pixeldroid.app.utils.api.objects.Collection
+import retrofit2.HttpException
+import java.io.IOException
+
+class CollectionsPagingSource(
+    private val api: PixelfedAPI,
+    private val accountId: String,
+) : PagingSource<String, Collection>() {
+    override suspend fun load(params: LoadParams<String>): LoadResult<String, Collection> {
+        return try {
+            val posts  = api.accountCollections(accountId)
+
+            LoadResult.Page(
+                data = posts,
+                prevKey = null,
+                //TODO pagination. For now, don't paginate
+                nextKey = null
+            )
+        } catch (exception: HttpException) {
+            LoadResult.Error(exception)
+        } catch (exception: IOException) {
+            LoadResult.Error(exception)
+        }
+    }
+
+    override fun getRefreshKey(state: PagingState<String, Collection>): String? = null
+}

app/src/main/java/org/pixeldroid/app/posts/feeds/uncachedFeeds/profile/ProfileContentRepository.kt

@@ -14,7 +14,8 @@ class ProfileContentRepository @ExperimentalPagingApi
 @Inject constructor(
     private val api: PixelfedAPI,
     private val accountId: String,
-    private val bookmarks: Boolean
+    private val bookmarks: Boolean,
+    private val collectionId: String?,
 ) : UncachedContentRepository<Status> {
     override fun getStream(): Flow<PagingData<Status>> {
         return Pager(
@@ -22,8 +23,9 @@ class ProfileContentRepository @ExperimentalPagingApi
                 initialLoadSize = NETWORK_PAGE_SIZE,
                 pageSize = NETWORK_PAGE_SIZE),
             pagingSourceFactory = {
-                ProfilePagingSource(api, accountId, bookmarks)
+                ProfilePagingSource(api, accountId, bookmarks, collectionId)
-            }
+            },
+            initialKey = if(collectionId != null) "1" else null
         ).flow
     }
 

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

@@ -10,13 +10,20 @@ import java.io.IOException
 class ProfilePagingSource(
     private val api: PixelfedAPI,
     private val accountId: String,
-    private val bookmarks: Boolean
+    private val bookmarks: Boolean,
+    private val collectionId: String?,
 ) : PagingSource<String, Status>() {
     override suspend fun load(params: LoadParams<String>): LoadResult<String, Status> {
         val position = params.key
         return try {
             val posts =
-                if(bookmarks) {
+                if(collectionId != null){
+                    api.collectionItems(
+                        collectionId,
+                        page = position
+                    )
+                }
+                else if(bookmarks) {
                     api.bookmarks(
                         limit = params.loadSize,
                         max_id = position
@@ -34,7 +41,9 @@ class ProfilePagingSource(
             LoadResult.Page(
                 data = posts,
                 prevKey = null,
-                nextKey = if(nextKey == position) null else nextKey
+                nextKey = if(collectionId != null ) {
+                    if(posts.isEmpty()) null else (params.key?.toIntOrNull()?.plus(1))?.toString()
+                } else if(nextKey == position) null else nextKey
             )
         } catch (exception: HttpException) {
             LoadResult.Error(exception)

app/src/main/java/org/pixeldroid/app/profile/CollectionActivity.kt

@@ -0,0 +1,141 @@
+package org.pixeldroid.app.profile
+
+import android.app.AlertDialog
+import android.content.Intent
+import android.os.Bundle
+import android.view.Menu
+import android.view.MenuInflater
+import android.view.MenuItem
+import androidx.lifecycle.lifecycleScope
+import com.google.android.material.snackbar.Snackbar
+import kotlinx.coroutines.launch
+import org.pixeldroid.app.R
+import org.pixeldroid.app.databinding.ActivityCollectionBinding
+import org.pixeldroid.app.profile.ProfileFeedFragment.Companion.COLLECTION
+import org.pixeldroid.app.profile.ProfileFeedFragment.Companion.COLLECTION_ID
+import org.pixeldroid.app.utils.BaseThemedWithBarActivity
+import org.pixeldroid.app.utils.api.PixelfedAPI
+import org.pixeldroid.app.utils.api.objects.Collection
+import retrofit2.HttpException
+import java.io.IOException
+
+class CollectionActivity : BaseThemedWithBarActivity() {
+    private lateinit var binding: ActivityCollectionBinding
+
+    private lateinit var collection: Collection
+    private var addCollection: Boolean = false
+    private var deleteFromCollection: Boolean = false
+
+    companion object {
+        const val COLLECTION_TAG = "Collection"
+        const val ADD_COLLECTION_TAG = "AddCollection"
+        const val DELETE_FROM_COLLECTION_TAG = "DeleteFromCollection"
+        const val DELETE_FROM_COLLECTION_RESULT = "DeleteFromCollectionResult"
+        const val ADD_TO_COLLECTION_RESULT = "AddToCollectionResult"
+    }
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        binding = ActivityCollectionBinding.inflate(layoutInflater)
+        setContentView(binding.root)
+
+        supportActionBar?.setDisplayHomeAsUpEnabled(true)
+
+        collection = intent.getSerializableExtra(COLLECTION_TAG) as Collection
+
+
+        addCollection = intent.getBooleanExtra(ADD_COLLECTION_TAG, false)
+        deleteFromCollection = intent.getBooleanExtra(DELETE_FROM_COLLECTION_TAG, false)
+
+        val addedResult = intent.getBooleanExtra(ADD_TO_COLLECTION_RESULT, false)
+        val deletedResult = intent.getBooleanExtra(DELETE_FROM_COLLECTION_RESULT, false)
+
+        if(addedResult)
+            Snackbar.make(
+                binding.root, getString(R.string.added_post_to_collection),
+                Snackbar.LENGTH_LONG
+            ).show()
+        else if (deletedResult) Snackbar.make(
+            binding.root, getString(R.string.removed_post_from_collection),
+            Snackbar.LENGTH_LONG
+        ).show()
+
+        supportActionBar?.title = if(addCollection) getString(R.string.add_to_collection)
+                        else if(deleteFromCollection) getString(R.string.delete_from_collection)
+                        else getString(R.string.collection_title).format(collection.username)
+
+        val collectionFragment = ProfileFeedFragment()
+        collectionFragment.arguments = Bundle().apply {
+            putBoolean(COLLECTION, true)
+            putString(COLLECTION_ID, collection.id)
+            putSerializable(COLLECTION, collection)
+            if(addCollection) putBoolean(ADD_COLLECTION_TAG, true)
+            else if (deleteFromCollection) putBoolean(DELETE_FROM_COLLECTION_TAG, true)
+        }
+
+        supportFragmentManager.beginTransaction()
+            .add(R.id.collectionFragment, collectionFragment).commit()
+    }
+
+    override fun onCreateOptionsMenu(menu: Menu): Boolean {
+        val userId = db.userDao().getActiveUser()?.user_id
+
+        // Only show options for editing a collection if it's the user's collection
+        if(!(addCollection || deleteFromCollection) && userId != null && collection.pid == userId) {
+            val inflater: MenuInflater = menuInflater
+            inflater.inflate(R.menu.collection_menu, menu)
+        }
+        return true
+    }
+
+    override fun onNewIntent(intent: Intent?) {
+        // Relaunch same activity, to avoid duplicates in history
+        super.onNewIntent(intent);
+        finish();
+        startActivity(intent);
+    }
+
+    override fun onOptionsItemSelected(item: MenuItem): Boolean {
+        return when (item.itemId) {
+            R.id.delete_collection -> {
+                AlertDialog.Builder(this).apply {
+                    setMessage(R.string.delete_collection_warning)
+                    setPositiveButton(android.R.string.ok) { _, _ ->
+                        // Delete collection
+                        lifecycleScope.launch {
+                            val api: PixelfedAPI = apiHolder.api ?: apiHolder.setToCurrentUser()
+                            try {
+                                api.deleteCollection(collection.id)
+                                // Deleted, exit activity
+                                finish()
+                            } catch (exception: IOException) {
+                                TODO("Error")
+                            } catch (exception: HttpException) {
+                                TODO("Error")
+                            }
+                        }
+                    }
+                    setNegativeButton(android.R.string.cancel) { _, _ -> }
+                }.show()
+                true
+            }
+            R.id.add_post_collection -> {
+                val intent = Intent(this, CollectionActivity::class.java)
+                intent.putExtra(COLLECTION_TAG, collection)
+                intent.putExtra(ADD_COLLECTION_TAG, true)
+                startActivity(intent)
+                true
+            }
+            R.id.remove_post_collection -> {
+                val intent = Intent(this, CollectionActivity::class.java)
+                intent.putExtra(COLLECTION_TAG, collection)
+                intent.putExtra(DELETE_FROM_COLLECTION_TAG, true)
+                startActivity(intent)
+                true
+            }
+            else -> super.onOptionsItemSelected(item)
+        }
+    }
+
+
+}

app/src/main/java/org/pixeldroid/app/profile/ProfileActivity.kt

@@ -65,40 +65,44 @@ class ProfileActivity : BaseThemedWithBarActivity() {
     private fun createProfileTabs(account: Account?): Array<Fragment>{
 
         val profileFeedFragment = ProfileFeedFragment()
-        val argumentsFeed = Bundle().apply {
+        profileFeedFragment.arguments = Bundle().apply {
             putSerializable(Account.ACCOUNT_TAG, account)
             putSerializable(ProfileFeedFragment.PROFILE_GRID, false)
             putSerializable(ProfileFeedFragment.BOOKMARKS, false)
         }
-        profileFeedFragment.arguments = argumentsFeed
 
         val profileGridFragment = ProfileFeedFragment()
-        val argumentsGrid = Bundle().apply {
+        profileGridFragment.arguments = Bundle().apply {
             putSerializable(Account.ACCOUNT_TAG, account)
             putSerializable(ProfileFeedFragment.PROFILE_GRID, true)
             putSerializable(ProfileFeedFragment.BOOKMARKS, false)
         }
-        profileGridFragment.arguments = argumentsGrid
+
+        val profileCollectionsFragment = ProfileFeedFragment()
+        profileCollectionsFragment.arguments = Bundle().apply {
+            putSerializable(Account.ACCOUNT_TAG, account)
+            putSerializable(ProfileFeedFragment.PROFILE_GRID, true)
+            putSerializable(ProfileFeedFragment.BOOKMARKS, false)
+            putSerializable(ProfileFeedFragment.COLLECTIONS, true)
+        }
+
+        val returnArray: Array<Fragment> = arrayOf(
+            profileGridFragment,
+            profileFeedFragment,
+            profileCollectionsFragment
+        )
 
         // If we are viewing our own account, show bookmarks
         if(account == null || account.id == user?.user_id) {
             val profileBookmarksFragment = ProfileFeedFragment()
-            val argumentsBookmarks = Bundle().apply {
+            profileBookmarksFragment.arguments = Bundle().apply {
                 putSerializable(Account.ACCOUNT_TAG, account)
                 putSerializable(ProfileFeedFragment.PROFILE_GRID, true)
                 putSerializable(ProfileFeedFragment.BOOKMARKS, true)
             }
-            profileBookmarksFragment.arguments = argumentsBookmarks
+            return returnArray + profileBookmarksFragment
-            return arrayOf(
-                profileGridFragment,
-                profileFeedFragment,
-                profileBookmarksFragment
-            )
         }
-        return arrayOf(
+        return returnArray
-            profileGridFragment,
-            profileFeedFragment
-        )
     }
 
     private fun setupTabs(
@@ -117,15 +121,19 @@ class ProfileActivity : BaseThemedWithBarActivity() {
             tab.tabLabelVisibility = TabLayout.TAB_LABEL_VISIBILITY_UNLABELED
             when (position) {
                 0 -> {
-                    tab.setText("Grid view")
+                    tab.setText(R.string.grid_view)
                     tab.setIcon(R.drawable.grid_on_black_24dp)
                 }
                 1 -> {
-                    tab.setText("Feed view")
+                    tab.setText(R.string.feed_view)
                     tab.setIcon(R.drawable.feed_view)
                 }
                 2 -> {
-                    tab.setText("Bookmarks")
+                    tab.setText(R.string.collections)
+                    tab.setIcon(R.drawable.collections)
+                }
+                3 -> {
+                    tab.setText(R.string.bookmarks)
                     tab.setIcon(R.drawable.bookmark)
                 }
             }

app/src/main/java/org/pixeldroid/app/profile/ProfileFeedFragment.kt

@@ -6,36 +6,55 @@ import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
 import android.widget.ImageView
+import androidx.lifecycle.LifecycleCoroutineScope
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.lifecycleScope
 import androidx.paging.ExperimentalPagingApi
 import androidx.paging.PagingDataAdapter
+import androidx.recyclerview.widget.DiffUtil
 import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import com.bumptech.glide.Glide
 import com.bumptech.glide.request.RequestOptions
+import com.google.android.material.snackbar.Snackbar
+import kotlinx.coroutines.launch
 import org.pixeldroid.app.R
 import org.pixeldroid.app.databinding.FragmentProfilePostsBinding
 import org.pixeldroid.app.posts.PostActivity
 import org.pixeldroid.app.posts.StatusViewHolder
-import org.pixeldroid.app.posts.feeds.UIMODEL_STATUS_COMPARATOR
 import org.pixeldroid.app.posts.feeds.uncachedFeeds.*
+import org.pixeldroid.app.posts.feeds.uncachedFeeds.profile.CollectionsContentRepository
 import org.pixeldroid.app.posts.feeds.uncachedFeeds.profile.ProfileContentRepository
+import org.pixeldroid.app.profile.CollectionActivity.Companion.ADD_COLLECTION_TAG
+import org.pixeldroid.app.profile.CollectionActivity.Companion.ADD_TO_COLLECTION_RESULT
+import org.pixeldroid.app.profile.CollectionActivity.Companion.DELETE_FROM_COLLECTION_RESULT
+import org.pixeldroid.app.profile.CollectionActivity.Companion.DELETE_FROM_COLLECTION_TAG
 import org.pixeldroid.app.utils.BlurHashDecoder
+import org.pixeldroid.app.utils.api.PixelfedAPI
 import org.pixeldroid.app.utils.api.objects.Account
 import org.pixeldroid.app.utils.api.objects.Attachment
+import org.pixeldroid.app.utils.api.objects.Collection
+import org.pixeldroid.app.utils.api.objects.FeedContent
 import org.pixeldroid.app.utils.api.objects.Status
 import org.pixeldroid.app.utils.db.entities.UserDatabaseEntity
 import org.pixeldroid.app.utils.displayDimensionsInPx
+import org.pixeldroid.app.utils.openUrl
 import org.pixeldroid.app.utils.setSquareImageFromURL
+import retrofit2.HttpException
+import java.io.IOException
 
 /**
  * Fragment to show a list of [Account]s, as a result of a search.
  */
-class ProfileFeedFragment : UncachedFeedFragment<Status>() {
+class ProfileFeedFragment : UncachedFeedFragment<FeedContent>() {
 
     companion object {
+        // List of collections
+        const val COLLECTIONS = "Collections"
+        // Content of collection
+        const val COLLECTION = "Collection"
+        const val COLLECTION_ID = "CollectionId"
         const val PROFILE_GRID = "ProfileGrid"
         const val BOOKMARKS = "Bookmarks"
     }
@@ -44,12 +63,27 @@ class ProfileFeedFragment : UncachedFeedFragment<Status>() {
     private var user: UserDatabaseEntity? = null
     private var grid: Boolean = true
     private var bookmarks: Boolean = false
+    private var collections: Boolean = false
+    private var collection: Collection? = null
+    private var addCollection: Boolean = false
+    private var deleteFromCollection: Boolean = false
+    private var collectionId: String? = null
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
 
-        grid = arguments?.getSerializable(PROFILE_GRID) as Boolean
+        grid = arguments?.getBoolean(PROFILE_GRID, true) ?: true
-        bookmarks = arguments?.getSerializable(BOOKMARKS) as Boolean
+        bookmarks = arguments?.getBoolean(BOOKMARKS) ?: false
+        collections = arguments?.getBoolean(COLLECTIONS) ?: false
+        collection = arguments?.getSerializable(COLLECTION) as? Collection
+        addCollection = arguments?.getBoolean(ADD_COLLECTION_TAG) ?: false
+        deleteFromCollection = arguments?.getBoolean(DELETE_FROM_COLLECTION_TAG) ?: false
+        collectionId = arguments?.getString(COLLECTION_ID)
+        if(addCollection){
+            // We want the user's profile, set all the rest to false to be sure
+            collections = false
+            bookmarks = false
+        }
         adapter = ProfilePostsAdapter()
 
         //get the currently active user
@@ -67,20 +101,23 @@ class ProfileFeedFragment : UncachedFeedFragment<Status>() {
 
         val view = super.onCreateView(inflater, container, savedInstanceState)
 
-        if(grid || bookmarks) {
+        if(grid || bookmarks || collections || addCollection) {
             binding.list.layoutManager = GridLayoutManager(context, 3)
         }
 
         // Get the view model
         @Suppress("UNCHECKED_CAST")
         viewModel = ViewModelProvider(requireActivity(), ProfileViewModelFactory(
-            ProfileContentRepository(
+            (if(!collections) ProfileContentRepository(
                 apiHolder.setToCurrentUser(),
                 accountId,
-                bookmarks
+                bookmarks,
+                if (addCollection) null else collectionId
             )
+            else CollectionsContentRepository(apiHolder.setToCurrentUser(), accountId)) as UncachedContentRepository<FeedContent>
         )
-        )[if(bookmarks) "Bookmarks" else "Profile", FeedViewModel::class.java] as FeedViewModel<Status>
+        )[if (addCollection) "AddCollection" else if (collections) "Collections" else if(bookmarks) "Bookmarks" else "Profile",
+                FeedViewModel::class.java] as FeedViewModel<FeedContent>
 
         launch()
         initSearch()
@@ -88,29 +125,122 @@ class ProfileFeedFragment : UncachedFeedFragment<Status>() {
         return view
     }
 
-    inner class ProfilePostsAdapter() : PagingDataAdapter<Status, RecyclerView.ViewHolder>(
+    inner class ProfilePostsAdapter : PagingDataAdapter<FeedContent, RecyclerView.ViewHolder>(
-        UIMODEL_STATUS_COMPARATOR
+        object : DiffUtil.ItemCallback<FeedContent>() {
+            override fun areItemsTheSame(oldItem: FeedContent, newItem: FeedContent): Boolean {
+                return oldItem.id == newItem.id
+            }
+
+            override fun areContentsTheSame(oldItem: FeedContent, newItem: FeedContent): Boolean =
+                oldItem.id == newItem.id
+        }
     ) {
 
         override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
-            return if(grid || bookmarks) {
+                return if(collections) {
+                    if (viewType == 1) {
+                        val view =
+                            LayoutInflater.from(parent.context)
+                                .inflate(R.layout.create_new_collection, parent, false)
+                        AddCollectionViewHolder(view)
+                    } else CollectionsViewHolder.create(parent)
+                }
+                else if(grid || bookmarks) {
                     ProfilePostsViewHolder.create(parent)
                 } else {
                     StatusViewHolder.create(parent)
                 }
         }
 
+        override fun getItemViewType(position: Int): Int {
+            return if(position == 0 && user?.user_id == accountId) 1
+            else 0
+        }
+
+        override fun getItemCount(): Int {
+            return if (collections && user?.user_id == accountId) {
+                super.getItemCount() + 1
+            } else super.getItemCount()
+        }
+
         override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
-            val post = getItem(position)
+            val post = if(collections && user?.user_id == accountId && position == 0) null else getItem(if(collections && user?.user_id == accountId) position - 1 else position)
 
             post?.let {
-                if(grid || bookmarks) {
+                if(collections) {
-                    (holder as ProfilePostsViewHolder).bind(it)
+                    (holder as CollectionsViewHolder).bind(it as Collection)
+                } else if(grid || bookmarks || addCollection) {
+                    (holder as ProfilePostsViewHolder).bind(
+                        it as Status,
+                        lifecycleScope,
+                        apiHolder.api ?: apiHolder.setToCurrentUser(),
+                        addCollection,
+                        collection,
+                        deleteFromCollection
+                    )
                 } else {
-                    (holder as StatusViewHolder).bind(it, apiHolder, db,
+                    (holder as StatusViewHolder).bind(it as Status, apiHolder, db,
                         lifecycleScope, requireContext().displayDimensionsInPx())
                 }
             }
+
+            if(collections && post == null){
+                (holder as AddCollectionViewHolder).itemView.setOnClickListener {
+                    val domain = user?.instance_uri
+                    val url = "$domain/i/collections/create"
+
+                    if(domain.isNullOrEmpty() || !requireContext().openUrl(url)) {
+                        Snackbar.make(binding.root, getString(R.string.new_collection_link_failed),
+                            Snackbar.LENGTH_LONG).show()
+                    }
+                }
+
+            }
+        }
+    }
+    class AddCollectionViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView)
+}
+
+
+class CollectionsViewHolder(binding: FragmentProfilePostsBinding) : RecyclerView.ViewHolder(binding.root) {
+    private val postPreview: ImageView = binding.postPreview
+    private val albumIcon: ImageView = binding.albumIcon
+    private val videoIcon: ImageView = binding.videoIcon
+
+    fun bind(collection: Collection) {
+
+        if (collection.post_count == 0){
+            //No media in this collection, so put a little icon there
+            postPreview.scaleX = 0.3f
+            postPreview.scaleY = 0.3f
+            Glide.with(postPreview).load(R.drawable.ic_comment_empty).into(postPreview)
+            albumIcon.visibility = View.GONE
+            videoIcon.visibility = View.GONE
+        } else {
+            postPreview.scaleX = 1f
+            postPreview.scaleY = 1f
+            setSquareImageFromURL(postPreview, collection.thumb, postPreview)
+            if (collection.post_count > 1) {
+                albumIcon.visibility = View.VISIBLE
+            } else {
+                albumIcon.visibility = View.GONE
+            }
+            videoIcon.visibility = View.GONE
+        }
+
+        postPreview.setOnClickListener {
+            val intent = Intent(postPreview.context, CollectionActivity::class.java)
+            intent.putExtra(CollectionActivity.COLLECTION_TAG, collection)
+            postPreview.context.startActivity(intent)
+        }
+    }
+
+    companion object {
+        fun create(parent: ViewGroup): CollectionsViewHolder {
+            val itemBinding = FragmentProfilePostsBinding.inflate(
+                LayoutInflater.from(parent.context), parent, false
+            )
+            return CollectionsViewHolder(itemBinding)
         }
     }
 }
@@ -120,7 +250,9 @@ class ProfilePostsViewHolder(binding: FragmentProfilePostsBinding) : RecyclerVie
     private val albumIcon: ImageView = binding.albumIcon
     private val videoIcon: ImageView = binding.videoIcon
 
-    fun bind(post: Status) {
+    fun bind(post: Status, lifecycleScope: LifecycleCoroutineScope, api: PixelfedAPI,
+             addCollection: Boolean = false, collection: Collection? = null, deleteFromCollection: Boolean = false
+    ) {
 
         if ((post.media_attachments?.size ?: 0) == 0){
             //No media in this post, so put a little icon there
@@ -158,11 +290,54 @@ class ProfilePostsViewHolder(binding: FragmentProfilePostsBinding) : RecyclerVie
         }
 
         postPreview.setOnClickListener {
+            if(addCollection && collection != null){
+                lifecycleScope.launch {
+                    try {
+                        api.addToCollection(collection.id, post.id)
+                        val intent = Intent(postPreview.context, CollectionActivity::class.java)
+                            .apply {
+                                addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)
+                                addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP)
+                                putExtra(ADD_TO_COLLECTION_RESULT, true)
+                                putExtra(CollectionActivity.COLLECTION_TAG, collection)
+                            }
+                        postPreview.context.startActivity(intent)
+                    } catch (exception: IOException) {
+                        Snackbar.make(postPreview, postPreview.context.getString(R.string.error_add_post_to_collection),
+                            Snackbar.LENGTH_LONG).show()
+                    } catch (exception: HttpException) {
+                        Snackbar.make(postPreview, postPreview.context.getString(R.string.error_add_post_to_collection),
+                            Snackbar.LENGTH_LONG).show()
+                    }
+                }
+            } else if (deleteFromCollection && (collection != null)){
+                lifecycleScope.launch {
+                    try {
+                        api.removeFromCollection(collection.id, post.id)
+                        val intent = Intent(postPreview.context, CollectionActivity::class.java)
+                            .apply {
+                                addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)
+                                addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP)
+                                putExtra(DELETE_FROM_COLLECTION_RESULT, true)
+                                putExtra(CollectionActivity.COLLECTION_TAG, collection)
+                            }
+                        postPreview.context.startActivity(intent)
+                    } catch (exception: IOException) {
+                        Snackbar.make(postPreview, postPreview.context.getString(R.string.error_remove_post_from_collection),
+                            Snackbar.LENGTH_LONG).show()
+                    } catch (exception: HttpException) {
+                        Snackbar.make(postPreview, postPreview.context.getString(R.string.error_remove_post_from_collection),
+                            Snackbar.LENGTH_LONG).show()
+                    }
+                }
+            }
+            else {
                 val intent = Intent(postPreview.context, PostActivity::class.java)
                 intent.putExtra(Status.POST_TAG, post)
                 postPreview.context.startActivity(intent)
             }
         }
+    }
 
     companion object {
         fun create(parent: ViewGroup): ProfilePostsViewHolder {
@@ -176,7 +351,7 @@ class ProfilePostsViewHolder(binding: FragmentProfilePostsBinding) : RecyclerVie
 
 
 class ProfileViewModelFactory @ExperimentalPagingApi constructor(
-    private val searchContentRepository: UncachedContentRepository<Status>
+    private val searchContentRepository: UncachedContentRepository<FeedContent>
 ) : ViewModelProvider.Factory {
 
     override fun <T : ViewModel> create(modelClass: Class<T>): T {

app/src/main/java/org/pixeldroid/app/utils/Utils.kt

@@ -95,7 +95,7 @@ fun normalizeDomain(domain: String): String {
             .trim(Char::isWhitespace)
 }
 
-fun BaseActivity.openUrl(url: String): Boolean {
+fun Context.openUrl(url: String): Boolean {
 
     val intent = CustomTabsIntent.Builder().build()
 

app/src/main/java/org/pixeldroid/app/utils/api/PixelfedAPI.kt

@@ -7,6 +7,7 @@ import okhttp3.Interceptor
 import org.pixeldroid.app.utils.api.objects.*
 import okhttp3.MultipartBody
 import okhttp3.OkHttpClient
+import org.pixeldroid.app.utils.api.objects.Collection
 import org.pixeldroid.app.utils.api.objects.Tag
 import org.pixeldroid.app.utils.db.AppDatabase
 import org.pixeldroid.app.utils.db.entities.UserDatabaseEntity
@@ -201,6 +202,33 @@ interface PixelfedAPI {
         @Path("id") statusId: String
     ) : Status
 
+    @GET("/api/v1.1/collections/accounts/{id}")
+    suspend fun accountCollections(
+        @Path("id") account_id: String? = null
+    ): List<Collection>
+
+    @GET("/api/v1.1/collections/items/{id}")
+    suspend fun collectionItems(
+        @Path("id") id: String,
+        @Query("page") page: String? = null
+    ): List<Status>
+
+    @DELETE("/api/v1.1/collections/delete/{id}")
+    suspend fun deleteCollection(
+        @Path("id") id: String,
+    )
+
+    @POST("/api/v1.1/collections/add")
+    suspend fun addToCollection(
+        @Query("collection_id") collection_id: String,
+        @Query("post_id") post_id: String,
+    ): Status
+
+    @POST("/api/v1.1/collections/remove")
+    suspend fun removeFromCollection(
+        @Query("collection_id") collection_id: String,
+        @Query("post_id") post_id: String,
+    )
 
     //Used in our case to retrieve comments for a given status
     @GET("/api/v1/statuses/{id}/context")

app/src/main/java/org/pixeldroid/app/utils/api/objects/Collection.kt

@@ -0,0 +1,22 @@
+package org.pixeldroid.app.utils.api.objects
+
+import java.io.Serializable
+import java.time.Instant
+
+data class Collection(
+    override val id: String, // Id of the profile
+    val pid: String, // Account id
+    val visibility: Visibility, // Public or private, or draft for your own collections
+    val title: String,
+    val description: String,
+    val thumb: String, // URL to the thumbnail of this collection
+    val updated_at: Instant,
+    val published_at: Instant,
+    val avatar: String, // URL to the avatar of the author of this collection
+    val username: String, // Username of author
+    val post_count: Int, //Number of posts in collection
+): FeedContent, Serializable {
+    enum class Visibility: Serializable {
+        public, private, draft
+    }
+}

app/src/main/res/drawable/collection_add.xml

@@ -0,0 +1,5 @@
+<vector android:height="24dp" android:tint="#FFFFFF"
+    android:viewportHeight="24" android:viewportWidth="24"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="@android:color/white" android:pathData="M4,6L2,6v14c0,1.1 0.9,2 2,2h14v-2L4,20L4,6zM20,2L8,2c-1.1,0 -2,0.9 -2,2v12c0,1.1 0.9,2 2,2h12c1.1,0 2,-0.9 2,-2L22,4c0,-1.1 -0.9,-2 -2,-2zM19,11h-4v4h-2v-4L9,11L9,9h4L13,5h2v4h4v2z"/>
+</vector>

app/src/main/res/drawable/collections.xml

@@ -0,0 +1,6 @@
+<vector android:height="24dp" android:tint="#FFFFFF"
+    android:viewportHeight="24" android:viewportWidth="24"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="@android:color/white" android:pathData="M4,6H2v14c0,1.1 0.9,2 2,2h14v-2H4V6z"/>
+    <path android:fillColor="@android:color/white" android:pathData="M20,2L8,2c-1.1,0 -2,0.9 -2,2v12c0,1.1 0.9,2 2,2h12c1.1,0 2,-0.9 2,-2L22,4c0,-1.1 -0.9,-2 -2,-2zM20,12l-2.5,-1.5L15,12L15,4h5v8z"/>
+</vector>

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

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".searchDiscover.TrendingActivity">
+
+    <FrameLayout
+        android:id = "@+id/collectionFragment"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"/>
+
+</androidx.constraintlayout.widget.ConstraintLayout>

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

@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="utf-8"?>
+<org.pixeldroid.app.postCreation.SquareLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:foreground="?selectableItemBackground"
+    android:clickable="true"
+    android:focusable="true">
+
+    <ImageView
+        android:id="@+id/addPhotoSquare"
+        android:layout_width="50dp"
+        android:layout_height="50dp"
+        android:layout_gravity="center"
+        android:layout_centerInParent="true"
+        android:layout_centerVertical="true"
+        android:backgroundTint="?attr/colorOnBackground"
+        android:background="@drawable/collection_add"
+        android:contentDescription="@string/add_photo" />
+</org.pixeldroid.app.postCreation.SquareLayout>

app/src/main/res/menu/collection_menu.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:android="http://schemas.android.com/apk/res/android">
+    <item
+        android:id="@+id/delete_collection"
+        android:enabled="true"
+        android:title="@string/delete_collection"/>
+   <item
+        android:id="@+id/add_post_collection"
+        android:enabled="true"
+        android:title="@string/collection_add_post"/>
+   <item
+        android:id="@+id/remove_post_collection"
+        android:enabled="true"
+        android:title="@string/collection_remove_post"/>
+</menu>

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

@@ -177,6 +177,7 @@ For more info about Pixelfed, you can check here: https://pixelfed.org"</string>
     <string name="save_image_success">Image successfully saved</string>
     <string name="follow_status_failed">Could not get follow status</string>
     <string name="edit_link_failed">Failed to open edit page</string>
+    <string name="new_collection_link_failed">Failed to open collection creation page</string>
     <string name="empty_feed">Nothing to see here :(</string>
     <string name="follow_button_failed">Could not display follow button</string>
     <string name="follow_error">Could not follow</string>
@@ -212,6 +213,7 @@ For more info about Pixelfed, you can check here: https://pixelfed.org"</string>
     <string name="license_info">PixelDroid is free and open source software, licensed under the GNU General Public License (version 3 or later)</string>
     <string name="about">About</string>
     <string name="post_title">%1$s\'s post</string>
+    <string name="collection_title">%1$s\'s collection</string>
     <string name="followers_title">%1$s\'s followers</string>
     <string name="hashtag_title">#%1$s</string>
     <string name="follows_title">%1$s\'s follows</string>
@@ -289,6 +291,20 @@ For more info about Pixelfed, you can check here: https://pixelfed.org"</string>
     <string name="daily_trending">View daily trending posts</string>
     <string name="trending_posts">Trending Posts</string>
     <string name="explore_posts">Explore random posts of the day</string>
+    <string name="grid_view">Grid view</string>
+    <string name="feed_view">Feed view</string>
+    <string name="bookmarks">Bookmarks</string>
+    <string name="collections">Collections</string>
+    <string name="delete_collection">Delete collection</string>
+    <string name="collection_add_post">Add post</string>
+    <string name="collection_remove_post">Remove post</string>
+    <string name="delete_collection_warning">Are you sure you want to delete this collection?</string>
+    <string name="add_to_collection">Choose a post to add</string>
+    <string name="delete_from_collection">Choose a post to remove</string>
+    <string name="added_post_to_collection">Added post to the collection</string>
+    <string name="error_add_post_to_collection">Failed to add post to the collection</string>
+    <string name="error_remove_post_from_collection">Failed to remove post from the collection</string>
+    <string name="removed_post_from_collection">Removed post from collection</string>
     <plurals name="replies_count">
         <item quantity="one">%d reply</item>
         <item quantity="other">%d replies</item>