refactor(filetree): implement double-tap-to-drag gesture to resolve scroll conflicts

Author: jatezzz

treeview/src/main/java/com/unnamed/b/atv/view/NodeTouchHandler.java

@@ -1,79 +1,47 @@
 package com.unnamed.b.atv.view;
 
 import android.annotation.SuppressLint;
+import android.view.GestureDetector;
 import android.view.HapticFeedbackConstants;
 import android.view.MotionEvent;
 import android.view.View;
-import android.view.ViewConfiguration;
+
+import androidx.annotation.NonNull;
+
 import com.unnamed.b.atv.model.TreeNode;
 
 class NodeTouchHandler implements View.OnTouchListener {
 
     private final TreeNode node;
     private final View view;
     private final TreeNode.TreeNodeDragListener defaultDragListener;
-    private final int touchSlop;
-    private final long longPressTimeout;
-
-    private float startX, startY;
-    private boolean isDragging = false;
-    private boolean isLongPressFired = false;
+    private final GestureDetector gestureDetector;
 
-    private final Runnable longPressRunnable;
+    private boolean isAwaitingDrag = false;
 
     NodeTouchHandler(TreeNode node, View view, TreeNode.TreeNodeDragListener defaultDragListener) {
         this.node = node;
         this.view = view;
         this.defaultDragListener = defaultDragListener;
-        this.touchSlop = ViewConfiguration.get(view.getContext()).getScaledTouchSlop();
-        this.longPressTimeout = ViewConfiguration.getLongPressTimeout();
-
-        this.longPressRunnable = () -> {
-            isLongPressFired = true;
-            this.view.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
-            this.view.performLongClick();
-        };
+
+        this.gestureDetector = new GestureDetector(view.getContext(), new GestureListener());
+        this.gestureDetector.setIsLongpressEnabled(true);
     }
 
     @SuppressLint("ClickableViewAccessibility")
     @Override
     public boolean onTouch(View v, MotionEvent event) {
-        switch (event.getAction()) {
-            case MotionEvent.ACTION_DOWN:
-                startX = event.getX();
-                startY = event.getY();
-                isDragging = isLongPressFired = false;
-                view.setPressed(true);
-                view.postDelayed(longPressRunnable, longPressTimeout);
-                return true;
+        gestureDetector.onTouchEvent(event);
 
-            case MotionEvent.ACTION_MOVE:
-                if (isDragging || isLongPressFired) break;
-
-                float dx = Math.abs(event.getX() - startX);
-                float dy = Math.abs(event.getY() - startY);
-
-                if (dx > (touchSlop * 2) || dy > (touchSlop * 2)) {
-                    isDragging = true;
-                    cancelPendingAction();
-                    dispatchDrag();
-                }
-                break;
-
-            case MotionEvent.ACTION_UP:
-            case MotionEvent.ACTION_CANCEL:
-                if (!isDragging && !isLongPressFired && event.getAction() == MotionEvent.ACTION_UP) {
-                    view.performClick();
-                }
-                cancelPendingAction();
-                break;
+        if (event.getAction() == MotionEvent.ACTION_UP || event.getAction() == MotionEvent.ACTION_CANCEL) {
+            isAwaitingDrag = false;
+            view.setPressed(false);
+        } else if (event.getAction() == MotionEvent.ACTION_MOVE && isAwaitingDrag) {
+            isAwaitingDrag = false;
+            dispatchDrag();
         }
-        return true;
-    }
 
-    private void cancelPendingAction() {
-        view.setPressed(false);
-        view.removeCallbacks(longPressRunnable);
+        return true;
     }
 
     private void dispatchDrag() {
@@ -82,7 +50,37 @@ private void dispatchDrag() {
             : defaultDragListener;
 
         if (listener != null) {
+            view.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
             listener.onStartDrag(node, node.getValue());
         }
     }
+
+    private class GestureListener extends GestureDetector.SimpleOnGestureListener {
+        @Override
+        public boolean onDown(@NonNull MotionEvent e) {
+            view.setPressed(true);
+            return true;
+        }
+
+        @Override
+        public boolean onSingleTapConfirmed(@NonNull MotionEvent e) {
+            view.performClick();
+            return true;
+        }
+
+        @Override
+        public void onLongPress(@NonNull MotionEvent e) {
+            view.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS);
+            view.performLongClick();
+        }
+
+        @Override
+        public boolean onDoubleTapEvent(MotionEvent e) {
+            if (e.getAction() == MotionEvent.ACTION_DOWN) {
+                isAwaitingDrag = true;
+                return true;
+            }
+            return super.onDoubleTapEvent(e);
+        }
+    }
 }