编写1.两个手指进行缩放布局 2.所有子控件也随着缩放的layout

1. 两个手指进行缩放布局

实现两个手指进行缩放布局，可以使用Android系统自带的GestureDetector和ScaleGestureDetector类。具体实现步骤如下：

1）创建一个自定义的View，重写onTouchEvent方法，实现手势监听；

2）在View的构造方法中创建GestureDetector和ScaleGestureDetector对象；

3）在onTouchEvent方法中调用GestureDetector和ScaleGestureDetector的onTouchEvent方法，分别监听单击、长按、滑动和缩放手势；

4）在onScale方法中获取当前缩放因子，设置View的缩放比例。

示例代码如下：

public class MyView extends View {
    private GestureDetector mGestureDetector;
    private ScaleGestureDetector mScaleGestureDetector;
    private float mScaleFactor = 1.0f;

    public MyView(Context context) {
        super(context);
        mGestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
            @Override
            public boolean onDown(MotionEvent e) {
                return true;
            }

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

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

            @Override
            public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
                // 滑动事件处理
                return true;
            }
        });
        mScaleGestureDetector = new ScaleGestureDetector(context, new ScaleGestureDetector.SimpleOnScaleGestureListener() {
            @Override
            public boolean onScale(ScaleGestureDetector detector) {
                mScaleFactor *= detector.getScaleFactor();
                mScaleFactor = Math.max(0.1f, Math.min(mScaleFactor, 10.0f)); // 设置缩放比例的上限和下限
                invalidate(); // 重绘View
                return true;
            }
        });
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        mGestureDetector.onTouchEvent(event);
        mScaleGestureDetector.onTouchEvent(event);
        return true;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.save();
        canvas.scale(mScaleFactor, mScaleFactor);
        // 绘制View的内容
        canvas.restore();
    }
}

2. 所有子控件也随着缩放的layout

如果要实现所有子控件随着缩放比例进行缩放，可以在ViewGroup的onLayout方法中遍历所有子控件，根据缩放比例重新计算子控件的位置和大小。示例代码如下：

public class MyViewGroup extends ViewGroup {
    private float mScaleFactor = 1.0f;

    public MyViewGroup(Context context) {
        super(context);
    }

    public MyViewGroup(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MyViewGroup(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        int childCount = getChildCount();
        for (int i = 0; i < childCount; i++) {
            View child = getChildAt(i);
            int left = (int) (child.getLeft() * mScaleFactor);
            int top = (int) (child.getTop() * mScaleFactor);
            int right = (int) (child.getRight() * mScaleFactor);
            int bottom = (int) (child.getBottom() * mScaleFactor);
            child.layout(left, top, right, bottom);
        }
    }

    @Override
    protected void dispatchDraw(Canvas canvas) {
        canvas.save();
        canvas.scale(mScaleFactor, mScaleFactor);
        super.dispatchDraw(canvas);
        canvas.restore();
    }

    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
        super.dispatchTouchEvent(ev);
        return true;
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        mGestureDetector.onTouchEvent(event);
        mScaleGestureDetector.onTouchEvent(event);
        return true;
    }

    private GestureDetector mGestureDetector = new GestureDetector(getContext(), new GestureDetector.SimpleOnGestureListener() {
        @Override
        public boolean onDown(MotionEvent e) {
            return true;
        }

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

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

        @Override
        public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
            // 滑动事件处理
            return true;
        }
    });

    private ScaleGestureDetector mScaleGestureDetector = new ScaleGestureDetector(getContext(), new ScaleGestureDetector.SimpleOnScaleGestureListener() {
        @Override
        public boolean onScale(ScaleGestureDetector detector) {
            mScaleFactor *= detector.getScaleFactor();
            mScaleFactor = Math.max(0.1f, Math.min(mScaleFactor, 10.0f)); // 设置缩放比例的上限和下限
            requestLayout(); // 重新布局View
            return true;
        }
    });
}