Android 开发：用 Instrumentation 实现屏幕中心两指外扩放大手势

在 Android 开发中，使用 Instrumentation 进行手势操作需要借助 TouchUtils 类。下面是一个示例代码，实现在屏幕中心执行一个两指外扩的放大手势：

import android.app.Instrumentation;
import android.test.TouchUtils;
import android.view.MotionEvent;

public class GestureExample {
    private static final int ACTION_POINTER_DOWN = 5;
    private static final int ACTION_POINTER_UP = 6;

    public static void main(String[] args) {
        Instrumentation instrumentation = new Instrumentation();

        // 获取屏幕的宽度和高度
        int screenWidth = instrumentation.getContext().getResources().getDisplayMetrics().widthPixels;
        int screenHeight = instrumentation.getContext().getResources().getDisplayMetrics().heightPixels;

        // 计算屏幕中心点的坐标
        int centerX = screenWidth / 2;
        int centerY = screenHeight / 2;

        // 计算两个手指的起始位置和结束位置
        int startDistance = 100; // 起始两指间的距离
        int endDistance = 300; // 结束两指间的距离
        int startX1 = centerX - startDistance / 2;
        int startY1 = centerY;
        int startX2 = centerX + startDistance / 2;
        int startY2 = centerY;
        int endX1 = centerX - endDistance / 2;
        int endY1 = centerY;
        int endX2 = centerX + endDistance / 2;
        int endY2 = centerY;

        // 模拟手势操作
        MotionEvent.PointerCoords[] pointerCoords = new MotionEvent.PointerCoords[2];
        pointerCoords[0] = new MotionEvent.PointerCoords();
        pointerCoords[0].x = startX1;
        pointerCoords[0].y = startY1;
        pointerCoords[1] = new MotionEvent.PointerCoords();
        pointerCoords[1].x = startX2;
        pointerCoords[1].y = startY2;

        long downTime = System.currentTimeMillis();
        long eventTime = System.currentTimeMillis();
        MotionEvent motionEvent = MotionEvent.obtain(downTime, eventTime, MotionEvent.ACTION_DOWN, 1, pointerCoords,
                MotionEvent.ACTION_POINTER_INDEX_MASK, 0, 0, 1, 1, 0, 0);
        instrumentation.sendPointerSync(motionEvent);

        eventTime = System.currentTimeMillis();
        motionEvent = MotionEvent.obtain(downTime, eventTime, ACTION_POINTER_DOWN, 2, pointerCoords,
                MotionEvent.ACTION_POINTER_INDEX_MASK, 0, 0, 1, 1, 0, 0);
        instrumentation.sendPointerSync(motionEvent);

        pointerCoords[0].x = endX1;
        pointerCoords[0].y = endY1;
        pointerCoords[1].x = endX2;
        pointerCoords[1].y = endY2;

        eventTime = System.currentTimeMillis();
        motionEvent = MotionEvent.obtain(downTime, eventTime, MotionEvent.ACTION_MOVE, 2, pointerCoords,
                MotionEvent.ACTION_POINTER_INDEX_MASK, 0, 0, 1, 1, 0, 0);
        instrumentation.sendPointerSync(motionEvent);

        eventTime = System.currentTimeMillis();
        motionEvent = MotionEvent.obtain(downTime, eventTime, ACTION_POINTER_UP, 2, pointerCoords,
                MotionEvent.ACTION_POINTER_INDEX_MASK, 0, 0, 1, 1, 0, 0);
        instrumentation.sendPointerSync(motionEvent);

        eventTime = System.currentTimeMillis();
        motionEvent = MotionEvent.obtain(downTime, eventTime, MotionEvent.ACTION_UP, 1, pointerCoords,
                MotionEvent.ACTION_POINTER_INDEX_MASK, 0, 0, 1, 1, 0, 0);
        instrumentation.sendPointerSync(motionEvent);
    }
}

请注意，该示例代码中使用的是Instrumentation类，因此它需要在Android应用中运行。您可以将该代码段添加到您的Android应用的某个地方（例如Activity的onCreate方法）进行测试。

希望这可以帮助到您！