Integrated AndroidTouchProcessor within the old FlutterView (flutter#…

…8095)

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

@@ -1,5 +1,6 @@
 package io.flutter.embedding.engine.android;
 
+import android.os.Build;
 import android.support.annotation.IntDef;
 import android.support.annotation.NonNull;
 import android.view.InputDevice;
@@ -36,7 +37,6 @@ public class AndroidTouchProcessor {
     int UP = 6;
   }
 
-
   // Must match the PointerDeviceKind enum in pointer.dart.
   @IntDef({
       PointerDeviceKind.TOUCH,
@@ -53,10 +53,24 @@ public class AndroidTouchProcessor {
     int UNKNOWN = 4;
   }
 
+  // Must match the PointerSignalKind enum in pointer.dart.
+  @IntDef({
+      PointerSignalKind.NONE,
+      PointerSignalKind.SCROLL,
+      PointerSignalKind.UNKNOWN
+  })
+  private @interface PointerSignalKind {
+    int NONE = 0;
+    int SCROLL = 1;
+    int UNKNOWN = 2;
+  }
+
   // Must match the unpacking code in hooks.dart.
-  // TODO(mattcarroll): Update with additional fields for scroll wheel support
-  private static final int POINTER_DATA_FIELD_COUNT = 21;
+  private static final int POINTER_DATA_FIELD_COUNT = 24;
   private static final int BYTES_PER_FIELD = 8;
+
+  // This value must match the value in framework's platform_view.dart.
+  // This flag indicates whether the original Android pointer events were batched together.
   private static final int POINTER_DATA_FLAG_BATCHED = 1;
 
   @NonNull
@@ -114,14 +128,45 @@ public boolean onTouchEvent(MotionEvent event) {
     }
 
     // Verify that the packet is the expected size.
-    assert packet.position() % (POINTER_DATA_FIELD_COUNT * BYTES_PER_FIELD) == 0;
+    if (packet.position() % (POINTER_DATA_FIELD_COUNT * BYTES_PER_FIELD) != 0) {
+      throw new AssertionError("Packet position is not on field boundary");
+    }
 
     // Send the packet to Flutter.
     renderer.dispatchPointerDataPacket(packet, packet.position());
 
     return true;
   }
 
+  /**
+   * Sends the given generic {@link MotionEvent} data to Flutter in a format that Flutter
+   * understands.
+   *
+   * Generic motion events include joystick movement, mouse hover, track pad touches, scroll wheel
+   * movements, etc.
+   */
+  public boolean onGenericMotionEvent(MotionEvent event) {
+    // Method isFromSource is only available in API 18+ (Jelly Bean MR2)
+    // Mouse hover support is not implemented for API < 18.
+    boolean isPointerEvent = Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2
+        && event.isFromSource(InputDevice.SOURCE_CLASS_POINTER);
+    if (!isPointerEvent || event.getActionMasked() != MotionEvent.ACTION_HOVER_MOVE) {
+      return false;
+    }
+
+    int pointerChange = getPointerChangeForAction(event.getActionMasked());
+    ByteBuffer packet = ByteBuffer.allocateDirect(
+        event.getPointerCount() * POINTER_DATA_FIELD_COUNT * BYTES_PER_FIELD
+    );
+    packet.order(ByteOrder.LITTLE_ENDIAN);
+
+    // ACTION_HOVER_MOVE always applies to a single pointer only.
+    addPointerForIndex(event, event.getActionIndex(), pointerChange, 0, packet);
+    assert(packet.position() % (POINTER_DATA_FIELD_COUNT * BYTES_PER_FIELD) != 0);
+    renderer.dispatchPointerDataPacket(packet, packet.position());
+    return true;
+  }
+
   // TODO(mattcarroll): consider creating a PointerPacket class instead of using a procedure that mutates inputs.
   private void addPointerForIndex(
       MotionEvent event,
@@ -136,11 +181,14 @@ private void addPointerForIndex(
 
     int pointerKind = getPointerDeviceTypeForToolType(event.getToolType(pointerIndex));
 
+    int signalKind = PointerSignalKind.NONE;
+
     long timeStamp = event.getEventTime() * 1000; // Convert from milliseconds to microseconds.
 
     packet.putLong(timeStamp); // time_stamp
     packet.putLong(pointerChange); // change
     packet.putLong(pointerKind); // kind
+    packet.putLong(signalKind); // signal_kind
     packet.putLong(event.getPointerId(pointerIndex)); // device
     packet.putDouble(event.getX(pointerIndex)); // physical_x
     packet.putDouble(event.getY(pointerIndex)); // physical_y
@@ -192,7 +240,10 @@ private void addPointerForIndex(
       packet.putDouble(0.0); // tilt
     }
 
-    packet.putLong(pointerData);
+    packet.putLong(pointerData); // platformData
+
+    packet.putDouble(0.0); // scroll_delta_x
+    packet.putDouble(0.0); // scroll_delta_y
   }
 
   @PointerChange

shell/platform/android/io/flutter/embedding/engine/android/FlutterView.java

@@ -312,12 +312,34 @@ public boolean onKeyDown(int keyCode, KeyEvent event) {
   @Override
   public boolean onTouchEvent(MotionEvent event) {
     if (!isAttachedToFlutterEngine()) {
-      return false;
+      return super.onTouchEvent(event);
+    }
+
+    // TODO(abarth): This version check might not be effective in some
+    // versions of Android that statically compile code and will be upset
+    // at the lack of |requestUnbufferedDispatch|. Instead, we should factor
+    // version-dependent code into separate classes for each supported
+    // version and dispatch dynamically.
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
+      requestUnbufferedDispatch(event);
     }
 
     return androidTouchProcessor.onTouchEvent(event);
   }
 
+  /**
+   * Invoked by Android when a generic motion event occurs, e.g., joystick movement, mouse hover,
+   * track pad touches, scroll wheel movements, etc.
+   *
+   * Flutter handles all of its own gesture detection and processing, therefore this
+   * method forwards all {@link MotionEvent} data from Android to Flutter.
+   */
+  @Override
+  public boolean onGenericMotionEvent(MotionEvent event) {
+    boolean handled = isAttachedToFlutterEngine() && androidTouchProcessor.onGenericMotionEvent(event);
+    return handled ? true : super.onGenericMotionEvent(event);
+  }
+
   /**
    * Invoked by Android when a hover-compliant input system causes a hover event.
    *
@@ -332,7 +354,7 @@ public boolean onTouchEvent(MotionEvent event) {
   @Override
   public boolean onHoverEvent(MotionEvent event) {
     if (!isAttachedToFlutterEngine()) {
-      return false;
+      return super.onHoverEvent(event);
     }
 
     // TODO(mattcarroll): hook up to accessibility.