实现类似QQ侧滑的SlidingLayout

最新推荐文章于 2024-05-19 09:40:59 发布

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最新推荐文章于 2024-05-19 09:40:59 发布

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分类专栏： Android功能实例文章标签： ViewDragHe SlidingLay

本文链接：https://blog.youkuaiyun.com/qq1377399077/article/details/53113884

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本文介绍了一种基于ViewDragHelper实现的侧滑布局组件SlidingLayout，详细解析了其核心代码及工作原理，包括触摸事件拦截、滑动距离计算、滑动状态管理等关键环节。

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SlidingLayout的侧滑效果通过ViewDragHelper来实现；
ViewDragHelper使用详解参考：http://www.jcodecraeer.com/a/anzhuokaifa/androidkaifa/2014/0911/1680.html

package com.zkr.cn.slidinglayout;

import android.content.Context;
import android.support.v4.view.ViewCompat;
import android.support.v4.widget.ViewDragHelper;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.FrameLayout;

/**
 * @PackageName: ---------com.zkr.cn.slidinglayout
 * @Description: ---------描述这个类的作用
 * @author: ---------------LF
 * @date: -----------------2016/11/9 17:15
 */
public class SlidingLayout extends FrameLayout {

    private ViewDragHelper mViewDragHelper;
    private View mMenuView,mMainView;
    private int mWidth;
    private float startX,startY;

    public SlidingLayout(Context context) {
        super(context);
        initView();
    }

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

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

    private void initView() {
        mViewDragHelper=ViewDragHelper.create(this,callBack);
    }

    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();
        mMenuView=getChildAt(0);
        mMainView=getChildAt(1);
    }

    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        mWidth=mMenuView.getMeasuredWidth();
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        return mViewDragHelper.shouldInterceptTouchEvent(ev);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        //将触摸事件传递给mViewDragHelper
        mViewDragHelper.processTouchEvent(event);
        return true;
    }

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

        //该条件下开始检测触摸事件
        @Override
        public boolean tryCaptureView(View child, int pointerId) {
            return mMainView==child;//当触摸的view为MainView则检测该事件
        }
        //不断返回水平滑动的距离
        @Override
        public int clampViewPositionHorizontal(View child, int left, int dx) {
            if(left>0){
                return left;
            }else{//禁止左滑
                return 0;
            }

        }

        //不断返回竖直滑动的距离
        @Override
        public int clampViewPositionVertical(View child, int top, int dy) {
            return 0;
        }

        //拖动结束后调用
        @Override
        public void onViewReleased(View releasedChild, float xvel, float yvel) {
            super.onViewReleased(releasedChild, xvel, yvel);
            //关闭菜单
            if(mMainView.getLeft()<300){
                mViewDragHelper.smoothSlideViewTo(mMainView,0,0);
                //invalidate方法类似
                ViewCompat.postInvalidateOnAnimation(SlidingLayout.this);
            }
            //打开菜单
            else{
                mViewDragHelper.smoothSlideViewTo(mMainView,300,0);
                ViewCompat.postInvalidateOnAnimation(SlidingLayout.this);
            }
        }
    };

    @Override
    public void computeScroll() {
       if(mViewDragHelper.continueSettling(true)){
            ViewCompat.postInvalidateOnAnimation(this);
       }
    }
}