ListView滑动删除

本来准备在ListView的每个Item的布局上设置一个隐藏的Button，当滑动的时候显示。但是因为每次只要存在一个Button，发现每个Item上的Button相互间不好控制。所以决定继承ListView然后结合PopupWindow。

首先是布局文件：

delete_btn.xml：这里只需要一个Button

  <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:orientation="vertical" >
       <Button
         android:id="@+id/id_item_btn"
         android:layout_width="60dp"
         android:singleLine="true"
         android:layout_height="wrap_content"
         android:text="删除"
         android:background="@drawable/d_delete_btn"
         android:textColor="#ffffff"
         android:paddingLeft="15dp"
         android:paddingRight="15dp"
         android:layout_alignParentRight="true"
         android:layout_centerVertical="true"
         android:layout_marginRight="15dp"
         />
 </LinearLayout> 

主布局文件：activity_main.xml，ListView的每个Item的样式直接使用了系统的android.R.layout.simple_list_item_1

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent" >  

     <com.example.listviewitemslidedeletebtnshow.QQListView
         android:id="@+id/id_listview"
         android:layout_width="fill_parent"
         android:layout_height="wrap_content" >
     </com.example.listviewitemslidedeletebtnshow.QQListView>  

 </RelativeLayout>  

接下来看看QQListView的实现：

 package com.example.listviewitemslidedeletebtnshow;  

 import android.content.Context;
 import android.util.AttributeSet;
 import android.view.Gravity;
 import android.view.LayoutInflater;
 import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewConfiguration;
 import android.widget.Button;
 import android.widget.LinearLayout;
 import android.widget.ListView;
 import android.widget.PopupWindow;  

 public class QQListView extends ListView
 {  

     private static final String TAG = "QQlistView";  

     // private static final int VELOCITY_SANP = 200;
     // private VelocityTracker mVelocityTracker;
     /**
      * 用户滑动的最小距离
      */
     private int touchSlop;  

     /**
      * 是否响应滑动
      */
     private boolean isSliding;  

     /**
      * 手指按下时的x坐标
      */
     private int xDown;
     /**
      * 手指按下时的y坐标
      */
     private int yDown;
     /**
      * 手指移动时的x坐标
      */
     private int xMove;
     /**
      * 手指移动时的y坐标
      */
     private int yMove;  

     private LayoutInflater mInflater;  

     private PopupWindow mPopupWindow;
     private int mPopupWindowHeight;
     private int mPopupWindowWidth;  

     private Button mDelBtn;
     /**
      * 为删除按钮提供一个回调接口
      */
     private DelButtonClickListener mListener;  

     /**
      * 当前手指触摸的View
      */
     private View mCurrentView;  

     /**
      * 当前手指触摸的位置
      */
     private int mCurrentViewPos;  

     /**
      * 必要的一些初始化
      *
      * @param context
      * @param attrs
      */
     public QQListView(Context context, AttributeSet attrs)
     {
         super(context, attrs);  

         mInflater = LayoutInflater.from(context);
         touchSlop = ViewConfiguration.get(context).getScaledTouchSlop();  

         View view = mInflater.inflate(R.layout.delete_btn, null);
         mDelBtn = (Button) view.findViewById(R.id.id_item_btn);
         mPopupWindow = new PopupWindow(view, LinearLayout.LayoutParams.WRAP_CONTENT,
                 LinearLayout.LayoutParams.WRAP_CONTENT);
         /**
          * 先调用下measure,否则拿不到宽和高
          */
         mPopupWindow.getContentView().measure(0, 0);
         mPopupWindowHeight = mPopupWindow.getContentView().getMeasuredHeight();
         mPopupWindowWidth = mPopupWindow.getContentView().getMeasuredWidth();
     }  

     @Override
     public boolean dispatchTouchEvent(MotionEvent ev)
     {
         int action = ev.getAction();
         int x = (int) ev.getX();
         int y = (int) ev.getY();
         switch (action)
         {  

         case MotionEvent.ACTION_DOWN:
             xDown = x;
             yDown = y;
             /**
              * 如果当前popupWindow显示，则直接隐藏，然后屏蔽ListView的touch事件的下传
              */
             if (mPopupWindow.isShowing())
             {
                 dismissPopWindow();
                 return false;
             }
             // 获得当前手指按下时的item的位置
             mCurrentViewPos = pointToPosition(xDown, yDown);
             // 获得当前手指按下时的item
             View view = getChildAt(mCurrentViewPos - getFirstVisiblePosition());
             mCurrentView = view;
             break;
         case MotionEvent.ACTION_MOVE:
             xMove = x;
             yMove = y;
             int dx = xMove - xDown;
             int dy = yMove - yDown;
             /**
              * 判断是否是从右到左的滑动
              */
             if (xMove < xDown && Math.abs(dx) > touchSlop && Math.abs(dy) < touchSlop)
             {
                 // Log.e(TAG, "touchslop = " + touchSlop + " , dx = " + dx +
                 // " , dy = " + dy);
                 isSliding = true;
             }
             break;
         }
         return super.dispatchTouchEvent(ev);
     }  

     @Override
     public boolean onTouchEvent(MotionEvent ev)
     {
         int action = ev.getAction();
         /**
          * 如果是从右到左的滑动才相应
          */
         if (isSliding)
         {
             switch (action)
             {
             case MotionEvent.ACTION_MOVE:  

                 int[] location = new int[2];
                 // 获得当前item的位置x与y
                 mCurrentView.getLocationOnScreen(location);
                 // 设置popupWindow的动画
                 mPopupWindow.setAnimationStyle(R.style.popwindow_delete_btn_anim_style);
                 mPopupWindow.update();
                 mPopupWindow.showAtLocation(mCurrentView, Gravity.LEFT | Gravity.TOP,
                         location[0] + mCurrentView.getWidth(), location[1] + mCurrentView.getHeight() / 2
                                 - mPopupWindowHeight / 2);
                 // 设置删除按钮的回调
                 mDelBtn.setOnClickListener(new OnClickListener()
                 {
                     @Override
                     public void onClick(View v)
                     {
                         if (mListener != null)
                         {
                             mListener.clickHappend(mCurrentViewPos);
                             mPopupWindow.dismiss();
                         }
                     }
                 });
                 // Log.e(TAG, "mPopupWindow.getHeight()=" + mPopupWindowHeight);  

                 break;
             case MotionEvent.ACTION_UP:
                 isSliding = false;  

             }
             // 相应滑动期间屏幕itemClick事件，避免发生冲突
             return true;
         }  

         return super.onTouchEvent(ev);
     }  

     /**
      * 隐藏popupWindow
      */
     private void dismissPopWindow()
     {
         if (mPopupWindow != null && mPopupWindow.isShowing())
         {
             mPopupWindow.dismiss();
         }
     }  

     public void setDelButtonClickListener(DelButtonClickListener listener)
     {
         mListener = listener;
     }  

     interface DelButtonClickListener
     {
         public void clickHappend(int position);
     }  

 }  

代码注释写得很详细，简单说一下，在dispatchTouchEvent中设置当前是否响应用户滑动，然后在onTouchEvent中判断是否响应，如果响应则popupWindow以动画的形式展示出来。当然屏幕上如果存在PopupWindow则屏幕ListView的滚动与Item的点击，以及从右到左滑动时屏幕Item的click事件。

接下来是MainActivity.java，这里代码很简单不做介绍了。

 package com.example.listviewitemslidedeletebtnshow;  

 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;  

 import android.app.Activity;
 import android.os.Bundle;
 import android.view.View;
 import android.widget.AdapterView;
 import android.widget.AdapterView.OnItemClickListener;
 import android.widget.ArrayAdapter;
 import android.widget.Toast;  

 import com.example.listviewitemslidedeletebtnshow.QQListView.DelButtonClickListener;  

 public class MainActivity extends Activity
 {
     private QQListView mListView;
     private ArrayAdapter<String> mAdapter;
     private List<String> mDatas;  

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

         mListView = (QQListView) findViewById(R.id.id_listview);
         // 不要直接Arrays.asList
         mDatas = new ArrayList<String>(Arrays.asList("HelloWorld", "Welcome", "Java", "Android", "Servlet", "Struts",
                 "Hibernate", "Spring", "HTML5", "Javascript", "Lucene"));
         mAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, mDatas);
         mListView.setAdapter(mAdapter);  

         mListView.setDelButtonClickListener(new DelButtonClickListener()
         {
             @Override
             public void clickHappend(final int position)
             {
                 Toast.makeText(MainActivity.this, position + " : " + mAdapter.getItem(position), 1).show();
                 mAdapter.remove(mAdapter.getItem(position));
             }
         });  

         mListView.setOnItemClickListener(new OnItemClickListener()
         {
             @Override
             public void onItemClick(AdapterView<?> parent, View view, int position, long id)
             {
                 Toast.makeText(MainActivity.this, position + " : " + mAdapter.getItem(position), 1).show();
             }
         });
     }
 }  

效果图如下：楼主使用asm.jar以及gifcamera截的gif，由于button的动画很短感觉截图效果很卡不流畅，大家有什么好的截图，还望推荐。有兴趣的还是下载源码看看效果i。

源码下载：http://download.csdn.net/detail/lmj623565791/7148325

上述文章实现的功能是:在ListView的Item上从右向左滑时，出现删除按钮，点击删除按钮把Item删除。

看过文章后，感觉没有必要把dispatchTouchEvent()和onTouchEvent()两个方法都重写，只要重写onTouchEvent就好了。于是对代码作了一些调整：

MyListView.java

 public class MyListView extends ListView {
     private static final String TAG = "MyListView";
     private int mTouchSlop;
     private int mXDown;
     private int mYDown;
     private int mCurrentPosition;
     private View mCurrentView;
     private PopupWindow mPopupWindow;
     private LayoutInflater mInflater;
     private boolean isSliding = false;
     // 为删除按钮提供一个回调接口
     private DelButtonClickListener mListener;
     private Button mDelBtn;
     private int mPopupWindowHeight;
     private int mPopupWindowWidth;

     public MyListView(Context context, AttributeSet attrs) {
         super(context, attrs);
         mInflater = LayoutInflater.from(context);
         mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();

         View view = mInflater.inflate(R.layout.delete_btn, null);
         mDelBtn = (Button) view.findViewById(R.id.id_item_btn);
         mPopupWindow = new PopupWindow(view, LinearLayout.LayoutParams.WRAP_CONTENT,
                 LinearLayout.LayoutParams.WRAP_CONTENT);
         // 如果需要通过点击PopupWindow之外的地方使其消失，则需要setFocusable(true).
         mPopupWindow.setFocusable(true);
         // Android 6.0以前的版本需要setBackgroundDrawable()，
         // 才能实现通过点击PopupWindow之外的地方使其消失的功能。
         mPopupWindow.setBackgroundDrawable(new ColorDrawable(0));
         // 先调用下measure，否则拿不到宽和高
         mPopupWindow.getContentView().measure(0, 0);
         mPopupWindowHeight = mPopupWindow.getContentView().getMeasuredHeight();
         mPopupWindowWidth = mPopupWindow.getContentView().getMeasuredWidth();
     }

     @Override
     public boolean onTouchEvent(MotionEvent ev) {
         int action = ev.getAction();
         int x = (int) ev.getX();
         int y = (int) ev.getY();

         switch (action){
             case MotionEvent.ACTION_DOWN:
                 isSliding = false;
                 mXDown = x;
                 mYDown = y;
                 mCurrentPosition = pointToPosition(mXDown, mYDown);
                 View view = getChildAt(mCurrentPosition - getFirstVisiblePosition());
                 mCurrentView = view;
                 break;
             case MotionEvent.ACTION_MOVE:
                 int dx = x - mXDown;
                 int dy = y - mYDown;

                 Log.d(TAG, "mTouchSlop = " + mTouchSlop + ", dx = " + dx + ", dy = " + dy);

                 if(mXDown > x && Math.abs(dx) > mTouchSlop && Math.abs(dy) < mTouchSlop){
                     Log.d(TAG, "isSliding");
                     isSliding = true;
                     int[] location = new int[2];
                     mCurrentView.getLocationOnScreen(location);
                     mPopupWindow.setAnimationStyle(R.style.popwindow_delete_btn_anim_style);
                     mPopupWindow.update();
                     Log.d(TAG, "Height: " + mCurrentView.getHeight() + "," + mPopupWindow.getHeight());
                     mPopupWindow.showAtLocation(mCurrentView, Gravity.NO_GRAVITY,
                             location[0] + mCurrentView.getWidth(),
                             location[1] + mCurrentView.getHeight() / 2 - mPopupWindowHeight / 2);
                     mDelBtn.setOnClickListener(new OnClickListener() {
                         @Override
                         public void onClick(View v) {
                             mListener.clickHappend(mCurrentPosition);
                             mPopupWindow.dismiss();
                         }
                     });
                 }
             case MotionEvent.ACTION_UP:
                 // isSliding 如果这里恢复为false,则后面会执行super.onTouchEvent事件，
                 // 而AbsListView的onTouchEvent调用了onTouchUp方法，在onTouchUp方法中有可能执行
                 // performClick.run() --> performItemClick() --> super.performItemClick
                 // --> mOnItemClickListener.onItemClick，这样最终触发Item的点击。
                 // 因此此处依旧保持isSliding为true的状态，而在ACTION_DOWN事件中恢复isSliding为false，
                 // 毕竟每个事件都以ACTION_DOWN开始。
                 //isSliding = false;
         }

         if(isSliding){
             return true;
         }

         return super.onTouchEvent(ev);
     }

     public void setDelButtonClickListener(DelButtonClickListener listener){
         mListener = listener;
     }

     interface DelButtonClickListener{
         public void clickHappend(int position);
     }
 }

 MyListView.java

通过这个例子学习到：

1、ListView的Item点击事件的触发过程：

自定义ListView的onTouchEvent()  ---调用super.onTouchEvent()---> AbsListView.onTouchEvent() ---MotionEvent.ACTION_UP---> AbsListView.onTouchUp()

---(有可能)调用performClick.run()---> AbsListView.PerformClick.run() ---调用performItemClick()--->AbsListView.performItemClick()

---(有可能)调用super.performItemClick()---> AdapterView.performItemClick() ---mOnItemClickListener.onItemClick---> OnItemClickListener.onItemClick()

也就是Item的点击事件是在MotionEvent.ACTION_UP事件完成的，这样在自定义ListView的onTouchEvent()中，对MotionEvent.ACTION_UP直接return true消费掉事件，而不要调用super.onTouchEvent。这样就避免了删除按钮与Item点击事件的冲突。

2、PopupWindow--通过点击PopupWindow之外的地方使其消失

a、需要调用setFocusable()方法（PopupWindow中showAtLocation() --> createPopupLayoutParams() -->computeFlags() --> 设置FLAG_NOT_FOCUSABLE）；

b、Android 6.0以前的版本需要setBackgroundDrawable()（具体原因见：PopupWindow的使用）。

原文：http://blog.csdn.net/lmj623565791/article/details/22961279

　　　http://www.cnblogs.com/yarightok/p/5666127.html