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