io.flutter.embedding.android.AndroidTouchProcessor Class Reference

Classes
interface	PointerChange
interface	PointerDeviceKind
interface	PointerSignalKind

Public Member Functions
	AndroidTouchProcessor (@NonNull FlutterRenderer renderer, boolean trackMotionEvents)
boolean	onTouchEvent (@NonNull MotionEvent event)
boolean	onTouchEvent (@NonNull MotionEvent event, @NonNull Matrix transformMatrix)
boolean	onGenericMotionEvent (@NonNull MotionEvent event, @NonNull Context context)

Static Package Attributes
static final int	BYTES_PER_FIELD = 8
static final int	DEFAULT_VERTICAL_SCROLL_FACTOR = 48
static final int	DEFAULT_HORIZONTAL_SCROLL_FACTOR = 48

Detailed Description

Sends touch information from Android to Flutter in a format that Flutter understands.

Definition at line 23 of file AndroidTouchProcessor.java.

Constructor & Destructor Documentation

AndroidTouchProcessor()

io.flutter.embedding.android.AndroidTouchProcessor.AndroidTouchProcessor ( @NonNull FlutterRenderer  renderer, boolean  trackMotionEvents  )

inline

Constructs an AndroidTouchProcessor that will send touch event data to the Flutter execution context represented by the given FlutterRenderer.

Parameters

renderer	The object that manages textures for rendering.
trackMotionEvents	This is used to query motion events when platform views are rendered.

Definition at line 122 of file AndroidTouchProcessor.java.

                                                                                             {
    this.renderer = renderer;
    this.motionEventTracker = MotionEventTracker.getInstance();
    this.trackMotionEvents = trackMotionEvents;
  }

Member Function Documentation

onGenericMotionEvent()

boolean io.flutter.embedding.android.AndroidTouchProcessor.onGenericMotionEvent ( @NonNull MotionEvent  event, @NonNull Context  context  )

inline

Sends the given generic 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.

Parameters

event	The generic motion event being processed.
context	For use by ViewConfiguration.get(context) to scale input.

Returns

True if the event was handled.

Definition at line 206 of file AndroidTouchProcessor.java.

                                                                                            {
    // Method isFromSource is only available in API 18+ (Jelly Bean MR2)
    // Mouse hover support is not implemented for API < 18.
    boolean isPointerEvent = event.isFromSource(InputDevice.SOURCE_CLASS_POINTER);
    boolean isMovementEvent =
        (event.getActionMasked() == MotionEvent.ACTION_HOVER_MOVE
            || event.getActionMasked() == MotionEvent.ACTION_SCROLL);
    if (isPointerEvent && isMovementEvent) {
      // Continue.
    } else {
      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, IDENTITY_TRANSFORM, packet, context);
    if (packet.position() % (POINTER_DATA_FIELD_COUNT * BYTES_PER_FIELD) != 0) {
      throw new AssertionError("Packet position is not on field boundary.");
    }
    renderer.dispatchPointerDataPacket(packet, packet.position());
    return true;
  }

onTouchEvent() [1/2]

boolean io.flutter.embedding.android.AndroidTouchProcessor.onTouchEvent ( @NonNull MotionEvent  event )

inline

Definition at line 128 of file AndroidTouchProcessor.java.

                                                          {
    return onTouchEvent(event, IDENTITY_TRANSFORM);
  }

onTouchEvent() [2/2]

boolean io.flutter.embedding.android.AndroidTouchProcessor.onTouchEvent ( @NonNull MotionEvent  event, @NonNull Matrix  transformMatrix  )

inline

Sends the given MotionEvent data to Flutter in a format that Flutter understands.

Parameters

event	The motion event from the view.
transformMatrix	Applies to the view that originated the event. It's used to transform the gesture pointers into screen coordinates.

Returns

True if the event was handled.

Definition at line 140 of file AndroidTouchProcessor.java.

                                                                                           {
    int pointerCount = event.getPointerCount();
 
    // The following packing code must match the struct in pointer_data.h.
 
    // Prepare a data packet of the appropriate size and order.
    ByteBuffer packet =
        ByteBuffer.allocateDirect(pointerCount * POINTER_DATA_FIELD_COUNT * BYTES_PER_FIELD);
    packet.order(ByteOrder.LITTLE_ENDIAN);
 
    int maskedAction = event.getActionMasked();
    int pointerChange = getPointerChangeForAction(event.getActionMasked());
    boolean updateForSinglePointer =
        maskedAction == MotionEvent.ACTION_DOWN || maskedAction == MotionEvent.ACTION_POINTER_DOWN;
    boolean updateForMultiplePointers =
        !updateForSinglePointer
            && (maskedAction == MotionEvent.ACTION_UP
                || maskedAction == MotionEvent.ACTION_POINTER_UP);
    if (updateForSinglePointer) {
      // ACTION_DOWN and ACTION_POINTER_DOWN always apply to a single pointer only.
      addPointerForIndex(event, event.getActionIndex(), pointerChange, 0, transformMatrix, packet);
    } else if (updateForMultiplePointers) {
      // ACTION_UP and ACTION_POINTER_UP may contain position updates for other pointers.
      // We are converting these updates to move events here in order to preserve this data.
      // We also mark these events with a flag in order to help the framework reassemble
      // the original Android event later, should it need to forward it to a PlatformView.
      for (int p = 0; p < pointerCount; p++) {
        if (p != event.getActionIndex() && event.getToolType(p) == MotionEvent.TOOL_TYPE_FINGER) {
          addPointerForIndex(
              event, p, PointerChange.MOVE, POINTER_DATA_FLAG_BATCHED, transformMatrix, packet);
        }
      }
      // It's important that we're sending the UP event last. This allows PlatformView
      // to correctly batch everything back into the original Android event if needed.
      addPointerForIndex(event, event.getActionIndex(), pointerChange, 0, transformMatrix, packet);
    } else {
      // ACTION_MOVE may not actually mean all pointers have moved
      // but it's the responsibility of a later part of the system to
      // ignore 0-deltas if desired.
      for (int p = 0; p < pointerCount; p++) {
        addPointerForIndex(event, p, pointerChange, 0, transformMatrix, packet);
      }
    }
 
    // Verify that the packet is the expected size.
    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;
  }

Member Data Documentation

BYTES_PER_FIELD

final int io.flutter.embedding.android.AndroidTouchProcessor.BYTES_PER_FIELD = 8

staticpackage

Definition at line 88 of file AndroidTouchProcessor.java.

DEFAULT_HORIZONTAL_SCROLL_FACTOR

final int io.flutter.embedding.android.AndroidTouchProcessor.DEFAULT_HORIZONTAL_SCROLL_FACTOR = 48

staticpackage

Definition at line 92 of file AndroidTouchProcessor.java.

DEFAULT_VERTICAL_SCROLL_FACTOR

final int io.flutter.embedding.android.AndroidTouchProcessor.DEFAULT_VERTICAL_SCROLL_FACTOR = 48

staticpackage

Definition at line 91 of file AndroidTouchProcessor.java.

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The documentation for this class was generated from the following file:

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