Load thumbnails using an asynchronous Glide target.

app/src/main/java/org/thoughtcrime/securesms/glide/GlideLiveDataTarget.java

@@ -0,0 +1,45 @@
+package org.thoughtcrime.securesms.glide;
+
+import android.graphics.Bitmap;
+import android.graphics.drawable.Drawable;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import androidx.lifecycle.LiveData;
+import androidx.lifecycle.MutableLiveData;
+
+import com.bumptech.glide.request.target.CustomTarget;
+import com.bumptech.glide.request.transition.Transition;
+
+/**
+ * A Glide target that exposes a LiveData<Bitmap> that can be observed.
+ *
+ * If the load is canceled or otherwise fails, it will post a null value.
+ */
+public class GlideLiveDataTarget extends CustomTarget<Bitmap> {
+
+  private final MutableLiveData<Bitmap> liveData = new MutableLiveData<>();
+
+  public GlideLiveDataTarget(int width, int height) {
+    super(width, height);
+  }
+
+  @Override
+  public void onResourceReady(@NonNull Bitmap resource, @Nullable Transition<? super Bitmap> transition) {
+    liveData.postValue(resource);
+  }
+
+  @Override
+  public void onLoadCleared(@Nullable Drawable placeholder) {
+    liveData.postValue(null);
+  }
+
+  @Override
+  public void onLoadFailed(@Nullable Drawable errorDrawable) {
+    liveData.postValue(null);
+  }
+
+  public @NonNull LiveData<Bitmap> getLiveData() {
+    return liveData;
+  }
+}