写一个TextureView的手势移动，放大，缩水，旋转代码

以下是一个简单的TextureView手势移动、放大、缩小、旋转的代码示例：

public class TextureViewGestureActivity extends AppCompatActivity implements TextureView.SurfaceTextureListener, GestureDetector.OnGestureListener, GestureDetector.OnDoubleTapListener {

    private TextureView mTextureView;
    private GestureDetector mGestureDetector;
    private Matrix mMatrix = new Matrix();
    private float mScaleFactor = 1.0f;
    private float mRotationDegrees = 0.f;
    private float mFocusX = 0.f;
    private float mFocusY = 0.f;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_textureview_gesture);

        mTextureView = findViewById(R.id.textureView);

        // 设置SurfaceTextureListener
        mTextureView.setSurfaceTextureListener(this);

        // 创建GestureDetector
        mGestureDetector = new GestureDetector(this, this);
        mGestureDetector.setOnDoubleTapListener(this);
    }

    // 实现SurfaceTextureListener接口
    @Override
    public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
        // TODO: 初始化Camera并将其与TextureView绑定
    }

    @Override
    public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
        // TODO: 处理TextureView大小变化的事件
    }

    @Override
    public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
        // TODO: 释放Camera资源
        return true;
    }

    @Override
    public void onSurfaceTextureUpdated(SurfaceTexture surface) {
        // TODO: 处理TextureView更新事件
    }

    // 实现GestureDetector.OnGestureListener接口
    @Override
    public boolean onDown(MotionEvent e) {
        return true;
    }

    @Override
    public boolean onSingleTapUp(MotionEvent e) {
        // TODO: 处理单击事件
        return true;
    }

    @Override
    public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
        // 处理拖动事件
        // 计算拖动的距离
        float dx = distanceX / mTextureView.getWidth() * 2;
        float dy = distanceY / mTextureView.getHeight() * 2;

        // 更新矩阵
        mMatrix.postTranslate(-dx, -dy);
        mTextureView.setTransform(mMatrix);

        return true;
    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        // TODO: 处理快速滑动事件
        return true;
    }

    @Override
    public void onLongPress(MotionEvent e) {
        // TODO: 处理长按事件
    }

    @Override
    public boolean onDoubleTap(MotionEvent e) {
        // TODO: 处理双击事件
        return true;
    }

    @Override
    public boolean onDoubleTapEvent(MotionEvent e) {
        return true;
    }

    @Override
    public boolean onSingleTapConfirmed(MotionEvent e) {
        // TODO: 处理单击事件
        return true;
    }

    // 处理缩放和旋转手势
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        mGestureDetector.onTouchEvent(event);

        int action = event.getActionMasked();

        if (action == MotionEvent.ACTION_DOWN) {
            // 记录焦点位置
            mFocusX = event.getX();
            mFocusY = event.getY();
        } else if (action == MotionEvent.ACTION_MOVE) {
            // 计算缩放比例和旋转角度
            float dx = event.getX() - mFocusX;
            float dy = event.getY() - mFocusY;
            float distance = (float) Math.sqrt(dx * dx + dy * dy);

            if (distance > 0) {
                // 处理缩放手势
                float scaleFactor = (float) Math.exp(distance / mTextureView.getWidth());
                mScaleFactor *= scaleFactor;
                mScaleFactor = Math.max(1.0f, Math.min(mScaleFactor, 4.0f));
                mMatrix.setScale(mScaleFactor, mScaleFactor, mFocusX, mFocusY);

                // 处理旋转手势
                mRotationDegrees = (float) Math.toDegrees(Math.atan2(dy, dx));
                mMatrix.postRotate(mRotationDegrees, mFocusX, mFocusY);

                mTextureView.setTransform(mMatrix);
            }
        }

        return true;
    }
}

在这个示例中，我们使用TextureView显示相机预览，然后处理拖动、放大、缩小和旋转手势。在处理缩放手势时，我们使用一个变量mScaleFactor来记录当前缩放比例，并使用Matrix.setScale()方法来更新矩阵。在处理旋转手势时，我们使用一个变量mRotationDegrees来记录当前旋转角度，并使用Matrix.postRotate()方法来更新矩阵。最后，我们使用TextureView.setTransform()方法将矩阵应用到TextureView上。