Fix expanding captions.

app/src/main/java/org/thoughtcrime/securesms/components/emoji/EmojiTextView.java

@@ -1,5 +1,6 @@
 package org.thoughtcrime.securesms.components.emoji;
 
+import android.annotation.SuppressLint;
 import android.content.Context;
 import android.content.res.TypedArray;
 import android.graphics.Canvas;
@@ -18,6 +19,8 @@ import android.text.method.TransformationMethod;
 import android.text.style.CharacterStyle;
 import android.util.AttributeSet;
 import android.util.TypedValue;
+import android.view.GestureDetector;
+import android.view.MotionEvent;
 import android.view.ViewGroup;
 
 import androidx.annotation.ColorInt;
@@ -25,6 +28,7 @@ import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.appcompat.widget.AppCompatTextView;
 import androidx.core.content.ContextCompat;
+import androidx.core.view.GestureDetectorCompat;
 import androidx.core.view.ViewKt;
 import androidx.core.widget.TextViewCompat;
 
@@ -315,6 +319,12 @@ public class EmojiTextView extends AppCompatTextView {
     }
   }
 
+  @SuppressLint("ClickableViewAccessibility")
+  public void bindGestureListener() {
+    GestureDetectorCompat gestureDetectorCompat = new GestureDetectorCompat(getContext(), new OnGestureListener());
+    setOnTouchListener((v, event) -> gestureDetectorCompat.onTouchEvent(event));
+  }
+
   private void ellipsizeAnyTextForMaxLength() {
     if (maxLength > 0 && getText().length() > maxLength + 1) {
       SpannableStringBuilder newContent = new SpannableStringBuilder();
@@ -465,4 +475,32 @@ public class EmojiTextView extends AppCompatTextView {
       mentionRendererDelegate.setTint(mentionBackgroundTint);
     }
   }
+
+  /**
+   * Due to some peculiarities in how TextView deals with touch events, it's really easy to accidentally trigger
+   * a click (say, when you try to scroll but you're at the bottom of a view.) Because of this, we handle these
+   * events manually.
+   */
+  private class OnGestureListener extends GestureDetector.SimpleOnGestureListener {
+    @Override
+    public boolean onDown(@NonNull MotionEvent e) {
+      return true;
+    }
+
+    @Override
+    public boolean onScroll(@NonNull MotionEvent e1, @NonNull MotionEvent e2, float distanceX, float distanceY) {
+      if (!canScrollVertically((int) distanceY)) {
+        return true;
+      }
+
+      int maxScrollDistance = computeVerticalScrollRange() - computeHorizontalScrollExtent();
+      scrollTo(0, Util.clamp(getScrollY() + (int) distanceY, 0, maxScrollDistance));
+      return true;
+    }
+
+    @Override
+    public boolean onSingleTapConfirmed(@NonNull MotionEvent e) {
+      return performClick();
+    }
+  }
 }