Add PagingMappingAdapter and convert GiphyMp4Adapter.

app/src/main/java/org/thoughtcrime/securesms/giph/model/GiphyImage.java

@@ -9,8 +9,9 @@ import androidx.annotation.Nullable;
 import com.fasterxml.jackson.annotation.JsonProperty;
 
 import org.thoughtcrime.securesms.util.ByteUnit;
+import org.thoughtcrime.securesms.util.adapter.mapping.MappingModel;
 
-public class GiphyImage {
+public class GiphyImage implements MappingModel<GiphyImage> {
 
   private static final int MAX_SIZE = (int) ByteUnit.MEGABYTES.toBytes(2);
 
@@ -20,6 +21,16 @@ public class GiphyImage {
   @JsonProperty("is_sticker")
   private boolean isSticker;
 
+  @Override
+  public boolean areItemsTheSame(@NonNull GiphyImage newItem) {
+    return getMp4Url().equals(newItem.getMp4Url());
+  }
+
+  @Override
+  public boolean areContentsTheSame(@NonNull GiphyImage newItem) {
+    return areItemsTheSame(newItem);
+  }
+
   public boolean isSticker() {
     return isSticker;
   }

app/src/main/java/org/thoughtcrime/securesms/giph/mp4/GiphyMp4Adapter.java

@@ -1,77 +1,24 @@
 package org.thoughtcrime.securesms.giph.mp4;
 
 
-import android.view.LayoutInflater;
-import android.view.View;
-import android.view.ViewGroup;
-
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
-import androidx.recyclerview.widget.DiffUtil;
-import androidx.recyclerview.widget.ListAdapter;
 
-import org.signal.paging.PagingController;
 import org.thoughtcrime.securesms.R;
 import org.thoughtcrime.securesms.giph.model.GiphyImage;
-
+import org.thoughtcrime.securesms.util.adapter.mapping.LayoutFactory;
-import java.util.Objects;
+import org.thoughtcrime.securesms.util.adapter.mapping.PagingMappingAdapter;
 
 /**
  * Maintains and displays a list of GiphyImage objects. This Adapter always displays gifs
  * as MP4 videos.
  */
-final class GiphyMp4Adapter extends ListAdapter<GiphyImage, GiphyMp4ViewHolder> {
+final class GiphyMp4Adapter extends PagingMappingAdapter<String> {
-
-  private final Callback                   listener;
-
-  private PagingController pagingController;
-
   public GiphyMp4Adapter(@Nullable Callback listener) {
-    super(new GiphyImageDiffUtilCallback());
+    registerFactory(GiphyImage.class, new LayoutFactory<>(v -> new GiphyMp4ViewHolder(v, listener), R.layout.giphy_mp4));
-
-    this.listener           = listener;
-  }
-
-  @Override
-  public @NonNull GiphyMp4ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
-    View itemView = LayoutInflater.from(parent.getContext())
-                                  .inflate(R.layout.giphy_mp4, parent, false);
-
-    return new GiphyMp4ViewHolder(itemView, listener);
-  }
-
-  @Override
-  public void onBindViewHolder(@NonNull GiphyMp4ViewHolder holder, int position) {
-    holder.onBind(getItem(position));
-  }
-
-  @Override
-  protected GiphyImage getItem(int position) {
-    if (pagingController != null) {
-      pagingController.onDataNeededAroundIndex(position);
-    }
-
-    return super.getItem(position);
-  }
-
-  void setPagingController(@Nullable PagingController pagingController) {
-    this.pagingController = pagingController;
   }
 
   interface Callback {
     void onClick(@NonNull GiphyImage giphyImage);
   }
-
-  private static final class GiphyImageDiffUtilCallback extends DiffUtil.ItemCallback<GiphyImage> {
-
-    @Override
-    public boolean areItemsTheSame(@NonNull GiphyImage oldItem, @NonNull GiphyImage newItem) {
-      return Objects.equals(oldItem.getMp4Url(), newItem.getMp4Url());
-    }
-
-    @Override
-    public boolean areContentsTheSame(@NonNull GiphyImage oldItem, @NonNull GiphyImage newItem) {
-      return areItemsTheSame(oldItem, newItem);
-    }
-  }
 }

app/src/main/java/org/thoughtcrime/securesms/giph/mp4/GiphyMp4ViewHolder.java

@@ -9,7 +9,6 @@ import android.widget.ImageView;
 
 import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
-import androidx.recyclerview.widget.RecyclerView;
 
 import com.bumptech.glide.load.engine.DiskCacheStrategy;
 import com.bumptech.glide.load.resource.drawable.DrawableTransitionOptions;
@@ -24,11 +23,12 @@ import org.thoughtcrime.securesms.mms.GlideApp;
 import org.thoughtcrime.securesms.util.Projection;
 import org.thoughtcrime.securesms.util.Util;
 import org.thoughtcrime.securesms.util.ViewUtil;
+import org.thoughtcrime.securesms.util.adapter.mapping.MappingViewHolder;
 
 /**
  * Holds a view which will either play back an MP4 gif or show its still.
  */
-final class GiphyMp4ViewHolder extends RecyclerView.ViewHolder implements GiphyMp4Playable {
+final class GiphyMp4ViewHolder extends MappingViewHolder<GiphyImage> implements GiphyMp4Playable {
 
   private static final Projection.Corners CORNERS = new Projection.Corners(ViewUtil.dpToPx(8));
 
@@ -52,7 +52,8 @@ final class GiphyMp4ViewHolder extends RecyclerView.ViewHolder implements GiphyM
     container.setResizeMode(AspectRatioFrameLayout.RESIZE_MODE_FIXED_WIDTH);
   }
 
-  void onBind(@NonNull GiphyImage giphyImage) {
+  @Override
+  public void bind(@NonNull GiphyImage giphyImage) {
     aspectRatio = giphyImage.getGifAspectRatio();
     mediaItem   = MediaItem.fromUri(Uri.parse(giphyImage.getMp4PreviewUrl()));
 

app/src/main/java/org/thoughtcrime/securesms/giph/mp4/GiphyMp4ViewModel.java

@@ -17,6 +17,7 @@ import org.signal.paging.PagingConfig;
 import org.signal.paging.PagingController;
 import org.thoughtcrime.securesms.giph.model.GiphyImage;
 import org.thoughtcrime.securesms.util.DefaultValueLiveData;
+import org.thoughtcrime.securesms.util.adapter.mapping.MappingModelList;
 import org.thoughtcrime.securesms.util.SingleLiveEvent;
 
 import java.util.List;
@@ -30,7 +31,7 @@ public final class GiphyMp4ViewModel extends ViewModel {
 
   private final GiphyMp4Repository                             repository;
   private final MutableLiveData<PagedData<String, GiphyImage>> pagedData;
-  private final LiveData<List<GiphyImage>>                     images;
+  private final LiveData<MappingModelList>                     images;
   private final LiveData<PagingController<String>>             pagingController;
   private final SingleLiveEvent<GiphyMp4SaveResult>            saveResultEvents;
   private final boolean                                        isForMms;
@@ -49,7 +50,7 @@ public final class GiphyMp4ViewModel extends ViewModel {
                                                                                                                 .filterNot(g -> TextUtils.isEmpty(isForMms ? g.getGifMmsUrl() : g.getGifUrl()))
                                                                                                                 .filterNot(g -> TextUtils.isEmpty(g.getMp4PreviewUrl()))
                                                                                                                 .filterNot(g -> TextUtils.isEmpty(g.getStillUrl()))
-                                                                                                                .toList()));
+                                                                                                                .collect(MappingModelList.toMappingModelList())));
   }
 
   LiveData<PagedData<String, GiphyImage>> getPagedData() {
@@ -73,7 +74,7 @@ public final class GiphyMp4ViewModel extends ViewModel {
     return saveResultEvents;
   }
 
-  public @NonNull LiveData<List<GiphyImage>> getImages() {
+  public @NonNull LiveData<MappingModelList> getImages() {
     return images;
   }
 

app/src/main/java/org/thoughtcrime/securesms/util/adapter/mapping/MappingAdapter.java

@@ -44,9 +44,9 @@ import kotlin.jvm.functions.Function1;
  */
 public class MappingAdapter extends ListAdapter<MappingModel<?>, MappingViewHolder<?>> {
 
-  private final Map<Integer, Factory<?>> factories;
+  final Map<Integer, Factory<?>> factories;
-  private final Map<Class<?>, Integer>   itemTypes;
+  final Map<Class<?>, Integer>   itemTypes;
-  private       int                      typeCount;
+        int                      typeCount;
 
   public MappingAdapter() {
     super(new MappingDiffCallback());

app/src/main/java/org/thoughtcrime/securesms/util/adapter/mapping/PagingMappingAdapter.java

@@ -0,0 +1,69 @@
+package org.thoughtcrime.securesms.util.adapter.mapping;
+
+import android.view.View;
+import android.widget.FrameLayout;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import org.signal.paging.PagingController;
+import org.thoughtcrime.securesms.util.ViewUtil;
+
+/**
+ * A specialized {@link MappingAdapter} backed by a {@link PagingController}.
+ */
+public class PagingMappingAdapter<Key> extends MappingAdapter {
+
+  private PagingController<Key> pagingController;
+
+  public PagingMappingAdapter() {
+    this(1, ViewUtil.dpToPx(100));
+  }
+
+  public PagingMappingAdapter(int placeHolderWidth, int placeHolderHeight) {
+    registerFactory(Placeholder.class, parent -> {
+      View view = new FrameLayout(parent.getContext());
+      view.setLayoutParams(new FrameLayout.LayoutParams(placeHolderWidth, placeHolderHeight));
+      return new MappingViewHolder.SimpleViewHolder<>(view);
+    });
+  }
+
+  public void setPagingController(@Nullable PagingController<Key> pagingController) {
+    this.pagingController = pagingController;
+  }
+
+  @Override
+  protected @Nullable MappingModel<?> getItem(int position) {
+    if (pagingController != null) {
+      pagingController.onDataNeededAroundIndex(position);
+    }
+    return super.getItem(position);
+  }
+
+  @Override
+  public int getItemViewType(int position) {
+    MappingModel<?> item = getItem(position);
+    if (item == null) {
+      //noinspection ConstantConditions
+      return itemTypes.get(Placeholder.class);
+    }
+
+    Integer type = itemTypes.get(item.getClass());
+    if (type != null) {
+      return type;
+    }
+    throw new AssertionError("No view holder factory for type: " + item.getClass());
+  }
+
+  private static class Placeholder implements MappingModel<Placeholder> {
+    @Override
+    public boolean areItemsTheSame(@NonNull Placeholder newItem) {
+      return false;
+    }
+
+    @Override
+    public boolean areContentsTheSame(@NonNull Placeholder newItem) {
+      return false;
+    }
+  }
+}