android listview 的弹性滑动 简单demo 实现

　　弹性滑动的效果比较好看。但是 在2.2以下版本中，android 本身没有实现，想要实现这中效果要自己去写
　　前几天在iteye上看见了一个博客给我很大的启示，于是自己动手实验了一下感觉还可以。在这里把我的源码给大家贴上让大家一起分享，希望大家也能提出更好的意见。废话不多说上源码：
　　1.自己些一个MyListview  继承listview 类：

package com.wljie;import android.content.Context;import android.graphics.Rect;import android.util.AttributeSet;import android.util.Log;import android.view.GestureDetector;import android.view.MotionEvent;import android.view.View;import android.view.GestureDetector.OnGestureListener;import android.view.animation.TranslateAnimation;import android.widget.ListView;public class MyListView extends ListView {private Context context;private boolean outBound = false;private int distance;private int firstOut;private static final String TAG = "wljie";public MyListView(Context context, AttributeSet attrs) {super(context, attrs);this.context = context;Log.d(TAG, "IN 1");}public MyListView(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);this.context = context;Log.d(TAG, "IN 2");}public MyListView(Context context) {super(context);this.context = context;Log.d(TAG, "IN 3");}GestureDetector gestureDetector = new GestureDetector(new OnGestureListener() {@Overridepublic boolean onSingleTapUp(MotionEvent e) {// TODO Auto-generated method stubreturn false;}@Overridepublic void onShowPress(MotionEvent e) {// TODO Auto-generated method stub}/*** 手势滑动的时候触发*/@Overridepublic boolean onScroll(MotionEvent e1, MotionEvent e2,float distanceX, float distanceY) {Log.d(TAG, "ENTER onscroll");int firstPos = getFirstVisiblePosition();int lastPos = getLastVisiblePosition();int itemCount = getCount();// outbound Topif (outBound && firstPos != 0 && lastPos != (itemCount - 1)) {scrollTo(0, 0);return false;}View firstView = getChildAt(firstPos);if (!outBound)firstOut = (int) e2.getRawY();if (firstView != null&& (outBound || (firstPos == 0&& firstView.getTop() == 0 && distanceY < 0))) {// Record the length of each slidedistance = firstOut - (int) e2.getRawY();scrollTo(0, distance / 2);return true;}// outbound Bottomreturn false;}@Overridepublic void onLongPress(MotionEvent e) {// TODO Auto-generated method stub}@Overridepublic boolean onFling(MotionEvent e1, MotionEvent e2,float velocityX, float velocityY) {// TODO Auto-generated method stubreturn false;}@Overridepublic boolean onDown(MotionEvent e) {// TODO Auto-generated method stubreturn false;}});@Overridepublic boolean dispatchTouchEvent(MotionEvent event) {Log.d(TAG, "dispatchTouchEvent");int act = event.getAction();if ((act == MotionEvent.ACTION_UP || act == MotionEvent.ACTION_CANCEL)&& outBound) {outBound = false;// scroll back}if (!gestureDetector.onTouchEvent(event)) {outBound = false;} else {outBound = true;}Rect rect = new Rect();        getLocalVisibleRect(rect);        TranslateAnimation am = new TranslateAnimation( 0, 0, -rect.top, 0);        am.setDuration(300);        startAnimation(am);        scrollTo(0, 0);return super.dispatchTouchEvent(event);}}

 

　　2.在main.xml 中写入

<?xml version="1.0" encoding="utf-8"?><LinearLayout        android:id="@+id/LinearLayout01"        android:layout_width="fill_parent"        android:layout_height="fill_parent"        xmlns:android="http://schemas.android.com/apk/res/android"        >        <com.wljie.MyListView        android:layout_width="wrap_content"                  android:layout_height="wrap_content"                  android:id="@+id/MyListView"/></LinearLayout>

 

　　3.创建一个my_listitem.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout        android:layout_width="fill_parent"        xmlns:android="http://schemas.android.com/apk/res/android"        android:orientation="vertical"        android:layout_height="wrap_content"        android:id="@+id/MyListItem"        android:paddingBottom="3dip"        android:paddingLeft="10dip">        <TextView                android:layout_height="wrap_content"                android:layout_width="fill_parent"                android:id="@+id/ItemTitle"                android:textSize="30dip">        </TextView>        <TextView                android:layout_height="wrap_content"                android:layout_width="fill_parent"                android:id="@+id/ItemText">        </TextView></LinearLayout>

 

　　4.在Main.java中进行下一步的显示

    package com.wljie;    import java.util.ArrayList;    import java.util.HashMap;    import android.app.Activity;    import android.graphics.Rect;    import android.os.Bundle;    import android.view.animation.TranslateAnimation;    import android.widget.SimpleAdapter;    public class Main extends Activity {    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.main);    // 绑定XML中的ListView，作为Item的容器    MyListView list = (MyListView) findViewById(R.id.MyListView);    // 生成动态数组，并且转载数据    ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();    for (int i = 0; i < 30; i++) {    HashMap<String, String> map = new HashMap<String, String>();    map.put("ItemTitle", "This is Title.....");    map.put("ItemText", "This is text.....");    mylist.add(map);    }    // 生成适配器，数组===》ListItem    SimpleAdapter mSchedule = new SimpleAdapter(this, // 没什么解释    mylist,// 数据来源    R.layout.my_listitem,// ListItem的XML实现    // 动态数组与ListItem对应的子项    new String[] { "ItemTitle", "ItemText" },    // ListItem的XML文件里面的两个TextView ID    new int[] { R.id.ItemTitle, R.id.ItemText });    // 添加并且显示    list.setAdapter(mSchedule);    }    }