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Android自定义View－SlideListView

在 android 中 ListView 可以说是使用最多的控件之一，ListView 有很多的用法和处理事件，比如 item 的点击和长按事件，在比较多的应用中，点击就是跳转，长按会弹出一些选择菜单等。这里我要介绍的是一个 ListView 侧滑出菜单的自定义控件

效果图如下：

正常状态

侧滑出菜单状态

分析

主要用到了 Scroller 这个滑动类，刚开始拦截触摸事件在 action ＝＝MotionEvent.ACTION_DOWN的时候，根据出点获取我们点击的itemView 然后根据滑动模式（左滑动 or 右滑动）来自动获取左侧或者右侧的宽度；

在 action == MotionEvent.ACTION_MOVE 中根据移动判断是否可以侧滑，以及侧滑的方向，并使用 itemView.scrollTo(deltaX, 0); 来移动itemView ；

最后在 ction == MotionEvent.ACTION_UP 中判断模式和移动的距离完成侧滑或者还原到初始状态。

实现

第一步初始化Scroller

scroller = new Scroller(context); mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();

第二步 action ＝＝MotionEvent.ACTION_DOWN

            case MotionEvent.ACTION_DOWN:                 if (this.mode == MOD_FORBID) {                     return super.onTouchEvent(ev);                 }                 // 如果处于侧滑完成状态，侧滑回去，并直接返回                 if (isSlided) {                     scrollBack();                     return false;                 }                 // 假如scroller滚动还没有结束，我们直接返回                 if (!scroller.isFinished()) {                     return false;                 }                   downX = (int) ev.getX();                 downY = (int) ev.getY();                   slidePosition = pointToPosition(downX, downY);                 // 无效的position, 不做任何处理                 if (slidePosition == AdapterView.INVALID_POSITION) {                     return super.onTouchEvent(ev);                 }                   // 获取我们点击的item view                 itemView = getChildAt(slidePosition - getFirstVisiblePosition());                 /*此处根据设置的滑动模式，自动获取左侧或右侧菜单的长度*/                 if (this.mode == MOD_BOTH) {                     this.leftLength = -itemView.getPaddingLeft();                     this.rightLength = -itemView.getPaddingRight();                 } else if (this.mode == MOD_LEFT) {                     this.leftLength = -itemView.getPaddingLeft();                 } else if (this.mode == MOD_RIGHT) {                     this.rightLength = -itemView.getPaddingRight();                 }                 break;

第三步 action == MotionEvent.ACTION_MOVE

            case MotionEvent.ACTION_MOVE:                 if (!canMove                         && slidePosition != AdapterView.INVALID_POSITION                         && (Math.abs(ev.getX() - downX) > mTouchSlop && Math.abs(ev                         .getY() - downY) < mTouchSlop)) {                     if (mSwipeLayout != null)                         mSwipeLayout.setEnabled(false);                     int offsetX = downX - lastX;                     if (offsetX > 0 && (this.mode == MOD_BOTH || this.mode == MOD_RIGHT)) {                         /*从右向左滑*/                         canMove = true;                     } else if (offsetX < 0 && (this.mode == MOD_BOTH || this.mode == MOD_LEFT)) {                         /*从左向右滑*/                         canMove = true;                     } else {                         canMove = false;                     }                     /*此段代码是为了避免我们在侧向滑动时同时触发ListView的OnItemClickListener时间*/                     MotionEventcancelEvent = MotionEvent.obtain(ev);                     cancelEvent                             .setAction(MotionEvent.ACTION_CANCEL                                     | (ev.getActionIndex() << MotionEvent.ACTION_POINTER_INDEX_SHIFT));                     onTouchEvent(cancelEvent);                 }                 if (canMove) {                     /*设置此属性，可以在侧向滑动时，保持ListView不会上下滚动*/                     requestDisallowInterceptTouchEvent(true);                     // 手指拖动itemView滚动, deltaX大于0向左滚动，小于0向右滚                     int deltaX = downX - lastX;                     if (deltaX < 0 && (this.mode == MOD_BOTH || this.mode == MOD_LEFT)) {                         /*向左滑*/                         itemView.scrollTo(deltaX, 0);                     } else if (deltaX > 0 && (this.mode == MOD_BOTH || this.mode == MOD_RIGHT)) {                         /*向右滑*/                         itemView.scrollTo(deltaX, 0);                     } else {                         itemView.scrollTo(0, 0);                     }                     return true;                 }                 break;

第四步 action == MotionEvent.ACTION_UP

            case MotionEvent.ACTION_UP:                 if (mSwipeLayout != null)                     mSwipeLayout.setEnabled(true);                 //requestDisallowInterceptTouchEvent(false);                 if (canMove){                     canMove = false;                     scrollByDistanceX();                 }                 break;

完整代码

一下是完整代码

package com.jwenfeng.fastdev.view;   importandroid.content.Context; importandroid.support.v4.widget.SwipeRefreshLayout; importandroid.util.AttributeSet; importandroid.view.MotionEvent; importandroid.view.View; importandroid.view.ViewConfiguration; importandroid.widget.AdapterView; importandroid.widget.ListView; importandroid.widget.Scroller;   /** * 当前类注释: ListView 侧滑出菜单 * 项目名：fastdev * 包名：com.jwenfeng.fastdev.view * 作者：jinwenfeng on 16/4/11 10:55 * 邮箱：823546371@qq.com * QQ： 823546371 * 公司：南京穆尊信息科技有限公司 * © 2016 jinwenfeng * ©版权所有，未经允许不得传播 */ public class SlideListView extends ListView {       /**下拉刷新view*/     private SwipeRefreshLayoutmSwipeLayout;     /**      * 禁止侧滑模式      */     public static int MOD_FORBID = 0;     /**      * 从左向右滑出菜单模式      */     public static int MOD_LEFT = 1;     /**      * 从右向左滑出菜单模式      */     public static int MOD_RIGHT = 2;     /**      * 左右均可以滑出菜单模式      */     public static int MOD_BOTH = 3;     /**      * 当前的模式      */     private int mode = MOD_FORBID;     /**      * 左侧菜单的长度      */     private int leftLength = 0;     /**      * 右侧菜单的长度      */     private int rightLength = 0;       /**      * 当前滑动的ListView position      */     private int slidePosition;     /**      * 手指按下X的坐标      */     private int downY;     /**      * 手指按下Y的坐标      */     private int downX;     /**      * ListView的item      */     private ViewitemView;     /**      * 滑动类      */     private Scrollerscroller;     /**      * 认为是用户滑动的最小距离      */     private int mTouchSlop;       /**      * 判断是否可以侧向滑动      */     private boolean canMove = false;     /**      * 标示是否完成侧滑      */     private boolean isSlided = false;       public SlideListView(Contextcontext) {         this(context, null);     }       public SlideListView(Contextcontext, AttributeSetattrs) {         this(context, attrs,0);     }       public SlideListView(Contextcontext, AttributeSetattrs, int defStyleAttr) {         super(context, attrs, defStyleAttr);         scroller = new Scroller(context);         mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();     }       /**      * 初始化菜单的滑出模式      *      * @param mode      */     public void initSlideMode(int mode) {         this.mode = mode;     }       /**      * 处理我们拖动ListView item的逻辑      */     @Override     public boolean onTouchEvent(MotionEventev) {         final int action = ev.getAction();         int lastX = (int) ev.getX();           switch (action) {             case MotionEvent.ACTION_DOWN:                 if (this.mode == MOD_FORBID) {                     return super.onTouchEvent(ev);                 }                 // 如果处于侧滑完成状态，侧滑回去，并直接返回                 if (isSlided) {                     scrollBack();                     return false;                 }                 // 假如scroller滚动还没有结束，我们直接返回                 if (!scroller.isFinished()) {                     return false;                 }                   downX = (int) ev.getX();                 downY = (int) ev.getY();                   slidePosition = pointToPosition(downX, downY);                 // 无效的position, 不做任何处理                 if (slidePosition == AdapterView.INVALID_POSITION) {                     return super.onTouchEvent(ev);                 }                   // 获取我们点击的item view                 itemView = getChildAt(slidePosition - getFirstVisiblePosition());                 /*此处根据设置的滑动模式，自动获取左侧或右侧菜单的长度*/                 if (this.mode == MOD_BOTH) {                     this.leftLength = -itemView.getPaddingLeft();                     this.rightLength = -itemView.getPaddingRight();                 } else if (this.mode == MOD_LEFT) {                     this.leftLength = -itemView.getPaddingLeft();                 } else if (this.mode == MOD_RIGHT) {                     this.rightLength = -itemView.getPaddingRight();                 }                 break;             case MotionEvent.ACTION_MOVE:                 if (!canMove                         && slidePosition != AdapterView.INVALID_POSITION                         && (Math.abs(ev.getX() - downX) > mTouchSlop && Math.abs(ev                         .getY() - downY) < mTouchSlop)) {                     if (mSwipeLayout != null)                         mSwipeLayout.setEnabled(false);                     int offsetX = downX - lastX;                     if (offsetX > 0 && (this.mode == MOD_BOTH || this.mode == MOD_RIGHT)) {                         /*从右向左滑*/                         canMove = true;                     } else if (offsetX < 0 && (this.mode == MOD_BOTH || this.mode == MOD_LEFT)) {                         /*从左向右滑*/                         canMove = true;                     } else {                         canMove = false;                     }                     /*此段代码是为了避免我们在侧向滑动时同时触发ListView的OnItemClickListener时间*/                     MotionEventcancelEvent = MotionEvent.obtain(ev);                     cancelEvent                             .setAction(MotionEvent.ACTION_CANCEL                                     | (ev.getActionIndex() << MotionEvent.ACTION_POINTER_INDEX_SHIFT));                     onTouchEvent(cancelEvent);                 }                 if (canMove) {                     /*设置此属性，可以在侧向滑动时，保持ListView不会上下滚动*/                     requestDisallowInterceptTouchEvent(true);                     // 手指拖动itemView滚动, deltaX大于0向左滚动，小于0向右滚                     int deltaX = downX - lastX;                     if (deltaX < 0 && (this.mode == MOD_BOTH || this.mode == MOD_LEFT)) {                         /*向左滑*/                         itemView.scrollTo(deltaX, 0);                     } else if (deltaX > 0 && (this.mode == MOD_BOTH || this.mode == MOD_RIGHT)) {                         /*向右滑*/                         itemView.scrollTo(deltaX, 0);                     } else {                         itemView.scrollTo(0, 0);                     }                     return true;                 }                 break;               case MotionEvent.ACTION_UP:                 if (mSwipeLayout != null)                     mSwipeLayout.setEnabled(true);                 //requestDisallowInterceptTouchEvent(false);                 if (canMove){                     canMove = false;                     scrollByDistanceX();                 }                 break;         }           return super.onTouchEvent(ev);     }       private void scrollByDistanceX() {         if(this.mode == MOD_FORBID){             return;         }         if(itemView.getScrollX() > 0 && (this.mode == MOD_BOTH || this.mode == MOD_RIGHT)){             /*从右向左滑*/             if (itemView.getScrollX() >= rightLength / 2) {                 scrollLeft();             }  else {                 // 滚回到原始位置                 scrollBack();             }         }else if(itemView.getScrollX() < 0 && (this.mode == MOD_BOTH || this.mode == MOD_LEFT)){             /*从左向右滑*/             if (itemView.getScrollX() <= -leftLength / 2) {                 scrollRight();             } else {                 // 滚回到原始位置                 scrollBack();             }         }else{             // 滚回到原始位置             scrollBack();         }     }       /**      * 往右滑动，getScrollX()返回的是左边缘的距离，就是以View左边缘为原点到开始滑动的距离，所以向右边滑动为负值      */     private void scrollRight() {         isSlided = true;         final int delta = (leftLength + itemView.getScrollX());         // 调用startScroll方法来设置一些滚动的参数，我们在computeScroll()方法中调用scrollTo来滚动item         scroller.startScroll(itemView.getScrollX(), 0, -delta, 0,                 Math.abs(delta));         postInvalidate(); // 刷新itemView     }       /**      * 向左滑动，根据上面我们知道向左滑动为正值      */     private void scrollLeft() {         isSlided = true;         final int delta = (rightLength - itemView.getScrollX());         // 调用startScroll方法来设置一些滚动的参数，我们在computeScroll()方法中调用scrollTo来滚动item         scroller.startScroll(itemView.getScrollX(), 0, delta, 0,                 Math.abs(delta));         postInvalidate(); // 刷新itemView       }       private void scrollBack() {         isSlided = false;         scroller.startScroll(itemView.getScrollX(), 0, -itemView.getScrollX(),                 0, Math.abs(itemView.getScrollX()));         postInvalidate(); // 刷新itemView     }       @Override     public void computeScroll() {         // 调用startScroll的时候scroller.computeScrollOffset()返回true，         if (scroller.computeScrollOffset()) {             // 让ListView item根据当前的滚动偏移量进行滚动             itemView.scrollTo(scroller.getCurrX(), scroller.getCurrY());             postInvalidate();         }     }       /**      * 提供给外部调用，用以将侧滑出来的滑回去      */     public void slideBack() {         this.scrollBack();     }       public void setSwipeLayout(SwipeRefreshLayoutmSwipeLayout) {         this.mSwipeLayout = mSwipeLayout;     } }