缩放系列（三）：一个可以手势缩放、拖拽、旋转的layout

2021-12-10 22:30:50

弄了一个下午，终于搞出来了，PowerfulLayout

下面是一个功能强大的改造的例子：

可以实现以下需求：

1.两个手指进行缩放布局

2.所有子控件也随着缩放，

3.子控件该有的功能不能丢失（像button有可被点击的功能，缩放后不能丢失该功能）

相对上个例子，多了一个功能---

4.拖拽（平移）layout

运行效果图：http://pan.baidu.com/s/1geIoG8r

图片太大就不贴出来了。

布局文件test.xml、超级简单的

<?xml version="1.0" encoding="utf-8"?>

<com.example.testbitmapscale.PowerfulLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical" >

<FrameLayout

    android:background="@drawable/home_tools"

    android:layout_width="match_parent"

    android:layout_height="match_parent" >

        <ImageButton

            android:id="@+id/imageButton2"

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:src="@drawable/selector_button1" />

</FrameLayout>

</com.example.testbitmapscale.PowerfulLayout>

java代码：

MainActivity也是超级简单

public class MainActivity extends ActionBarActivity {

    private View view;

    @Override

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        // setContentView(R.layout.test);

        view = View.inflate(this, R.layout.test, null);

        setContentView(view);

    }

//    @Override

//    public boolean onTouchEvent(MotionEvent event) {

//        if (event.getPointerCount() > 1) {

//            // 多点触控

//            // 返回给ScaleGestureDetector来处理

//            return mScaleGestureDetector.onTouchEvent(event);

//        } else {

//            // 单点触控

//            switch (event.getAction()) {

//            case MotionEvent.ACTION_DOWN:

//                downX = (int) event.getX();

//                downY = (int) event.getY();

//                newHeight = view.getLayoutParams().height;

//                newWidth = view.getLayoutParams().width;

////                 int widthMeasureSpec =

////                 View.MeasureSpec.makeMeasureSpec(2000,View.MeasureSpec.AT_MOST);

////

////                 int heightMeasureSpec

////                 =View.MeasureSpec.makeMeasureSpec(2000,View.MeasureSpec.AT_MOST);

////

////                 view.measure(widthMeasureSpec,heightMeasureSpec);

////

////                 newHeight = view.getMeasuredHeight();

////

////                 newWidth = view.getMeasuredWidth();

//                break;

//            case MotionEvent.ACTION_MOVE:

//                long currentTimeMillis = System.currentTimeMillis();

//                if (currentTimeMillis - lastMultiTouchTime > 200) {

//                    // 双指触控后要等待200毫秒才能执行单指触控的操作，避免双指触控后出现颤抖的情况

//                    int moveX = (int) event.getX();// 移动手指的时候手指的x

//                    int moveY = (int) event.getY();// 移动手指的时候手指的y

//                    int deltaX = (int) (moveX - downX);

//                    int deltaY = (int) (moveY - downY);

//                    int newLeft = left + deltaX;// view的新left

//                    int newTop = top + deltaY;// view的新top

//                    int newRight = right + deltaX;// view的新right

//                    int newBottom = bottom + deltaY;// view的新bottom

////                    int newWidth = (int) (preScale * originalWidth);

////                    int newHeight = (int) (preScale * originalHeight);

////                    if (deltaX>(newWidth-originalHeight)/2||deltaY>(newHeight-originalHeight)/2) {

////                        return false;

////                    }

//                    // int newWidth = view.getWidth();

//                    // int newHeight = view.getHeight();

//                    System.out.println("newWidth:" + newWidth + "newHeight:"

//                            + newHeight);

////                    System.out.println(preScale);

//                    if (newLeft < originalWidth - newWidth) {

//                        newLeft = originalWidth - newWidth;

//                        newRight = newLeft + newWidth;

//                    }

//                    // if (newTop < originalHeight - newHeight){

//                    // newTop = originalHeight - newHeight;

//                    // newBottom= newTop+newHeight;

//                    // }

//                    // if(newRight>originalWidth){

//                    // newRight=originalWidth;

//                    // newLeft=newRight-newWidth;

//                    // }

//                    // if(newBottom>originalHeight){

//                    // newBottom=originalHeight;

//                    // newTop=newBottom-newHeight;

//                    // }

//                    view.layout(newLeft, newTop, newRight, newBottom);// 重新摆放view的位置

//                } else {

//                    return false;

//                }

//

//                break;

//            case MotionEvent.ACTION_UP:

//                // 更新位置信息

//                left = view.getLeft();

//                top = view.getTop();

//                right = view.getRight();

//                bottom = view.getBottom();

//                break;

//

//            default:

//                break;

//            }

//            return true;// 代表消费了事件

//        }

//    }

}

PowerfulLayout.java:

package com.example.testbitmapscale;

import android.content.Context;

import android.support.v4.widget.ViewDragHelper;

import android.util.AttributeSet;

import android.view.MotionEvent;

import android.view.ScaleGestureDetector;

import android.view.View;

import android.widget.FrameLayout;

import com.nineoldandroids.view.ViewHelper;

public class PowerfulLayout extends FrameLayout {

    // 屏幕宽高

    private int screenHeight;

    private int screenWidth;

    private ViewDragHelper mDragHelper;

    private long lastMultiTouchTime;// 记录多点触控缩放后的时间

    private int originalWidth;// view宽度

    private int originalHeight;// view高度

    private ScaleGestureDetector mScaleGestureDetector = null;

    // private View view;

    private int downX;// 手指按下的x坐标值

    private int downY;// 手指按下的y坐标值

    private int left;// view的左坐标值

    private int top;// view的上坐标值

    private int right;// view的右坐标值

    private int bottom;// view的下坐标值

    private int newHeight;

    private int newWidth;

    private float scale;

    private float preScale = 1;// 默认前一次缩放比例为1

    public PowerfulLayout(Context context, AttributeSet attrs, int defStyleAttr) {

        super(context, attrs, defStyleAttr);

        init(context);

    }

    public PowerfulLayout(Context context, AttributeSet attrs) {

        super(context, attrs);

        init(context);

    }

    public PowerfulLayout(Context context) {

        super(context);

        init(context);

    }

    private void init(Context context) {

        mDragHelper = ViewDragHelper.create(this, callback);

        mScaleGestureDetector = new ScaleGestureDetector(context,

                new ScaleGestureListener());

        // view.post(new Runnable() {

        //

        // @Override

        // public void run() {

        // left = view.getLeft();

        // top = view.getTop();

        // right = view.getRight();

        // bottom = view.getBottom();

        // originalWidth = view.getWidth();

        // originalHeight = view.getHeight();

        // }

        // });

    }

    @Override

    protected void onSizeChanged(int w, int h, int oldw, int oldh) {

        super.onSizeChanged(w, h, oldw, oldh);

        screenWidth = getMeasuredWidth();

        screenHeight = getMeasuredHeight();

    }

    @Override

    public boolean onInterceptTouchEvent(MotionEvent ev) {

        super.onInterceptTouchEvent(ev);

        boolean b = mDragHelper.shouldInterceptTouchEvent(ev);// 由mDragHelper决定是否拦截事件，并传递给onTouchEvent

        return b;

    }

    private boolean needToHandle=true;

    @Override

    public boolean onTouchEvent(MotionEvent event) {

        int pointerCount = event.getPointerCount(); // 获得多少点

        if (pointerCount > 1) {// 多点触控，

            switch (event.getAction()) {

            case MotionEvent.ACTION_DOWN:

                needToHandle=false;

                break;

            case MotionEvent.ACTION_MOVE:

                break;

            case MotionEvent.ACTION_POINTER_2_UP://第二个手指抬起的时候

                needToHandle=true;

                break;

            default:

                break;

            }

            return mScaleGestureDetector.onTouchEvent(event);//让mScaleGestureDetector处理触摸事件

        } else {

            long currentTimeMillis = System.currentTimeMillis();

            if (currentTimeMillis - lastMultiTouchTime > 200&&needToHandle) {

//                  多点触控全部手指抬起后要等待200毫秒才能执行单指触控的操作，避免多点触控后出现颤抖的情况

                try {

                    mDragHelper.processTouchEvent(event);

                } catch (Exception e) {

                    e.printStackTrace();

                }

                return true;

            }

//            }

        }

        return false;

    }

    private ViewDragHelper.Callback callback = new ViewDragHelper.Callback() {

        /**

         * 用于判断是否捕获当前child的触摸事件

         *

         * @param child

         *            当前触摸的子view

         * @param pointerId

         * @return true就捕获并解析；false不捕获

         */

        @Override

        public boolean tryCaptureView(View child, int pointerId) {

            if (preScale > 1)

                return true;

            return false;

        }

        /**

         * 控制水平方向上的位置

         */

        @Override

        public int clampViewPositionHorizontal(View child, int left, int dx) {

            if (left < (screenWidth - screenWidth * preScale) / 2)

                left = (int) (screenWidth - screenWidth * preScale) / 2;// 限制mainView可向左移动到的位置

            if (left > (screenWidth * preScale - screenWidth) / 2)

                left = (int) (screenWidth * preScale - screenWidth) / 2;// 限制mainView可向右移动到的位置

            return left;

        }

        public int clampViewPositionVertical(View child, int top, int dy) {

            if (top < (screenHeight - screenHeight * preScale) / 2) {

                top = (int) (screenHeight - screenHeight * preScale) / 2;// 限制mainView可向上移动到的位置

            }

            if (top > (screenHeight * preScale - screenHeight) / 2) {

                top = (int) (screenHeight * preScale - screenHeight) / 2;// 限制mainView可向上移动到的位置

            }

            return top;

        }

    };

    public class ScaleGestureListener implements

            ScaleGestureDetector.OnScaleGestureListener {

        @Override

        public boolean onScale(ScaleGestureDetector detector) {

            float previousSpan = detector.getPreviousSpan();// 前一次双指间距

            float currentSpan = detector.getCurrentSpan();// 本次双指间距

            if (currentSpan < previousSpan) {

                // 缩小

                // scale = preScale-detector.getScaleFactor()/3;

                scale = preScale - (previousSpan - currentSpan) / 1000;

            } else {

                // 放大

                // scale = preScale+detector.getScaleFactor()/3;

                scale = preScale + (currentSpan - previousSpan) / 1000;

            }

            // 缩放view

            if (scale > 0.5) {

                ViewHelper.setScaleX(PowerfulLayout.this, scale);// x方向上缩放

                ViewHelper.setScaleY(PowerfulLayout.this, scale);// y方向上缩放

            }

            return false;

        }

        @Override

        public boolean onScaleBegin(ScaleGestureDetector detector) {

            // 一定要返回true才会进入onScale()这个函数

            return true;

        }

        @Override

        public void onScaleEnd(ScaleGestureDetector detector) {

            preScale = scale;// 记录本次缩放比例

            lastMultiTouchTime = System.currentTimeMillis();// 记录双指缩放后的时间

        }

    }

}

可以手势缩放、拖拽、旋转的layout应用场景，例子：qq侧滑菜单。侧滑的时候菜单中所有子控件跟随父控件从小变大，不过它不支持双指缩放，只是单指操作。链接：http://blog.csdn.net/qq_30948129/article/details/52282451

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