samples/SampleInputMethodAccessibilityService/src/com/example/android/sampleinputmethodaccessibilityservice/DragToMoveTouchListener.java

/*
 * Copyright (C) 2022 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.sampleinputmethodaccessibilityservice;

import android.view.MotionEvent;
import android.view.View;

final class DragToMoveTouchListener implements View.OnTouchListener {
    @FunctionalInterface
    interface OnMoveCallback {
        void onMove(int dx, int dy);
    }

    private final OnMoveCallback mCallback;
    private int mPointId = -1;
    private float mLastTouchX;
    private float mLastTouchY;

    DragToMoveTouchListener(OnMoveCallback callback) {
        mCallback = callback;
    }

    @Override
    public boolean onTouch(View v, MotionEvent event) {
        final int pointId = event.getPointerId(event.getActionIndex());
        switch (event.getAction()) {
            case MotionEvent.ACTION_POINTER_DOWN:
            case MotionEvent.ACTION_DOWN: {
                if (mPointId != -1) {
                    break;
                }
                v.setPressed(true);
                mPointId = pointId;
                mLastTouchX = event.getRawX();
                mLastTouchY = event.getRawY();
                break;
            }
            case MotionEvent.ACTION_MOVE: {
                if (pointId != mPointId) {
                    break;
                }
                final float x = event.getRawX();
                final float y = event.getRawY();
                final float dx = x - mLastTouchX;
                final float dy = y - mLastTouchY;
                mCallback.onMove((int) dx, (int) dy);
                mLastTouchX = x;
                mLastTouchY = y;
                break;
            }
            case MotionEvent.ACTION_POINTER_UP:
            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_CANCEL: {
                if (pointId != mPointId) {
                    break;
                }
                mPointId = -1;
                v.setPressed(false);
                break;
            }
            default:
                break;
        }
        return true;
    }
}