Fix unexpected pointer change issue and Add test case

shell/platform/android/io/flutter/embedding/android/AndroidTouchProcessor.java

@@ -224,12 +224,6 @@ private void addPointerForIndex(
       return;
     }
 
-    long motionEventId = 0;
-    if (trackMotionEvents) {
-      MotionEventTracker.MotionEventId trackedEvent = motionEventTracker.track(event);
-      motionEventId = trackedEvent.getId();
-    }
-
     int pointerKind = getPointerDeviceTypeForToolType(event.getToolType(pointerIndex));
     // We use this in lieu of using event.getRawX and event.getRawY as we wish to support
     // earlier versions than API level 29.
@@ -252,7 +246,20 @@ private void addPointerForIndex(
       buttons = 0;
     }
 
+    int panZoomType = -1;
     boolean isTrackpadPan = ongoingPans.containsKey(event.getPointerId(pointerIndex));
+    if (isTrackpadPan) {
+      panZoomType = getPointerChangeForPanZoom(pointerChange);
+      if (panZoomType == -1) {
+        return;
+      }
+    }
+
+    long motionEventId = 0;
+    if (trackMotionEvents) {
+      MotionEventTracker.MotionEventId trackedEvent = motionEventTracker.track(event);
+      motionEventId = trackedEvent.getId();
+    }
 
     int signalKind =
         event.getActionMasked() == MotionEvent.ACTION_SCROLL
@@ -264,7 +271,7 @@ private void addPointerForIndex(
     packet.putLong(motionEventId); // motionEventId
     packet.putLong(timeStamp); // time_stamp
     if (isTrackpadPan) {
-      packet.putLong(getPointerChangeForPanZoom(pointerChange)); // change
+      packet.putLong(panZoomType); // change
       packet.putLong(PointerDeviceKind.TRACKPAD); // kind
     } else {
       packet.putLong(pointerChange); // change
@@ -355,7 +362,7 @@ private void addPointerForIndex(
     packet.putDouble(1.0); // scale
     packet.putDouble(0.0); // rotation
 
-    if (isTrackpadPan && getPointerChangeForPanZoom(pointerChange) == PointerChange.PAN_ZOOM_END) {
+    if (isTrackpadPan && (panZoomType == PointerChange.PAN_ZOOM_END)) {
       ongoingPans.remove(event.getPointerId(pointerIndex));
     }
   }
@@ -401,7 +408,7 @@ private int getPointerChangeForPanZoom(int pointerChange) {
     } else if (pointerChange == PointerChange.UP || pointerChange == PointerChange.CANCEL) {
       return PointerChange.PAN_ZOOM_END;
     }
-    throw new AssertionError("Unexpected pointer change");
+    return -1;
   }
 
   @PointerDeviceKind

shell/platform/android/test/io/flutter/embedding/android/AndroidTouchProcessorTest.java

@@ -89,6 +89,7 @@ MotionEvent mockEvent(int action, float x, float y, int buttonState) {
       when(event.getX(0)).thenReturn(x);
       when(event.getY(0)).thenReturn(y);
       when(event.getToolType(0)).thenReturn(toolType);
+      when(event.isFromSource(InputDevice.SOURCE_CLASS_POINTER)).thenReturn(true);
       return event;
     }
   }
@@ -218,4 +219,59 @@ public void unexpectedMaskedAction() {
     touchProcessor.onTouchEvent(mocker.mockEvent(MotionEvent.ACTION_BUTTON_PRESS, 0.0f, 0.0f, 0));
     verify(mockRenderer, never()).dispatchPointerDataPacket(ByteBuffer.allocate(0), 0);
   }
+
+  @Test
+  public void unexpectedPointerChange() {
+    // Regression test for https://github.com/flutter/flutter/issues/129765
+
+    MotionEventMocker mocker =
+        new MotionEventMocker(0, InputDevice.SOURCE_MOUSE, MotionEvent.TOOL_TYPE_MOUSE);
+
+    touchProcessor.onTouchEvent(mocker.mockEvent(MotionEvent.ACTION_DOWN, 0.0f, 0.0f, 0));
+    InOrder inOrder = inOrder(mockRenderer);
+    inOrder
+        .verify(mockRenderer)
+        .dispatchPointerDataPacket(packetCaptor.capture(), packetSizeCaptor.capture());
+    ByteBuffer packet = packetCaptor.getValue();
+    assertEquals(AndroidTouchProcessor.PointerChange.PAN_ZOOM_START, readPointerChange(packet));
+    assertEquals(AndroidTouchProcessor.PointerDeviceKind.TRACKPAD, readPointerDeviceKind(packet));
+    assertEquals(AndroidTouchProcessor.PointerSignalKind.NONE, readPointerSignalKind(packet));
+    assertEquals(0.0, readPointerPhysicalX(packet));
+    assertEquals(0.0, readPointerPhysicalY(packet));
+
+    touchProcessor.onTouchEvent(mocker.mockEvent(MotionEvent.ACTION_MOVE, 10.0f, 5.0f, 0));
+    inOrder
+        .verify(mockRenderer)
+        .dispatchPointerDataPacket(packetCaptor.capture(), packetSizeCaptor.capture());
+    packet = packetCaptor.getValue();
+    assertEquals(AndroidTouchProcessor.PointerChange.PAN_ZOOM_UPDATE, readPointerChange(packet));
+    assertEquals(AndroidTouchProcessor.PointerDeviceKind.TRACKPAD, readPointerDeviceKind(packet));
+    assertEquals(AndroidTouchProcessor.PointerSignalKind.NONE, readPointerSignalKind(packet));
+    assertEquals(0.0, readPointerPhysicalX(packet));
+    assertEquals(0.0, readPointerPhysicalY(packet));
+    assertEquals(10.0, readPointerPanX(packet));
+    assertEquals(5.0, readPointerPanY(packet));
+
+    touchProcessor.onGenericMotionEvent(mocker.mockEvent(MotionEvent.ACTION_SCROLL, 0.0f, 0.0f, 0));
+    inOrder
+        .verify(mockRenderer)
+        .dispatchPointerDataPacket(packetCaptor.capture(), packetSizeCaptor.capture());
+    packet = packetCaptor.getValue();
+    packet.rewind();
+    while (packet.hasRemaining()) {
+      assertEquals(0, packet.get());
+    }
+
+    touchProcessor.onTouchEvent(mocker.mockEvent(MotionEvent.ACTION_UP, 10.0f, 5.0f, 0));
+    inOrder
+        .verify(mockRenderer)
+        .dispatchPointerDataPacket(packetCaptor.capture(), packetSizeCaptor.capture());
+    packet = packetCaptor.getValue();
+    assertEquals(AndroidTouchProcessor.PointerChange.PAN_ZOOM_END, readPointerChange(packet));
+    assertEquals(AndroidTouchProcessor.PointerDeviceKind.TRACKPAD, readPointerDeviceKind(packet));
+    assertEquals(AndroidTouchProcessor.PointerSignalKind.NONE, readPointerSignalKind(packet));
+    assertEquals(0.0, readPointerPhysicalX(packet));
+    assertEquals(0.0, readPointerPhysicalY(packet));
+    inOrder.verifyNoMoreInteractions();
+  }
 }