Android 自定义弹性ListView控件实例代码(三种方法)

关于在Android中实现ListView的弹性效果，有很多不同的方法，网上一搜，也有很多，下面贴出在项目中经常用到的两种实现ListView弹性效果的方法（基本上拿来就可以用），供大家参考:

弹性ListView

第一种方法：

import android.content.Context;
import android.content.res.Configuration;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.view.View;
import android.view.ViewConfiguration;
import android.widget.ListView;
import java.lang.reflect.Field;
import java.lang.reflect.Modifier;
/**
* Created by Noah on 2016/1/16.
*/
public class BounceListView extends ListView {
private static final float MAX_Y_OVERSCROLL_DISTANCE = 200;
private float mMaxYOverscrollDistance;
public BounceListView(Context context) {
this(context,null);
}
public BounceListView(Context context,AttributeSet attrs) {
this(context,attrs,0);
}
public BounceListView(Context context,AttributeSet attrs,int defStyleAttr) {
super(context,defStyleAttr);
initBounceListView();
}
private void initBounceListView(){
final DisplayMetrics metrics = getContext().getResources().getDisplayMetrics();
final float density = metrics.density;
mMaxYOverscrollDistance = (int) (density * MAX_Y_OVERSCROLL_DISTANCE);
}
@Override
protected boolean overScrollBy(int deltaX,int deltaY,int scrollX,int scrollY,int scrollRangeX,int scrollRangeY,int maxOverScrollX,int maxOverScrollY,boolean isTouchEvent) {
return super.overScrollBy(deltaX,deltaY,scrollX,scrollY,scrollRangeX,scrollRangeY,maxOverScrollX,(int)mMaxYOverscrollDistance,isTouchEvent);
}
/**
* 设置本App所有的ListView弹性粒度
* @param ctx
* @param size
* @return
*/
public boolean configGlobalMaxOverScrollDistance(Context ctx,int size)
{
try {
final DisplayMetrics metrics = ctx.getResources().getDisplayMetrics();
final float density = metrics.density;
int value = (int) (density * size);
mMaxYOverscrollDistance = value;
ViewConfiguration config = ViewConfiguration.get(ctx);
Field mOverscrollDistance = ViewConfiguration.class.getDeclaredField("mOverscrollDistance");
if(!mOverscrollDistance.isAccessible() || !Modifier.isPublic(mOverscrollDistance.getModifiers()))
{
mOverscrollDistance.setAccessible(true);
}
mOverscrollDistance.setInt(config,value);
} catch (Exception e) {
e.printStackTrace();
return false;
}
return true;
}
}

第二种比较简单，好容易理解，只是动态改变了ListView在Y轴上的可移动距离，代码如下：

import android.content.Context; 
import android.util.AttributeSet; 
import android.util.DisplayMetrics; 
import android.widget.ListView; 
/** 
* 弹性ListView。 
* @author E 
*/ 
public class FlexiListView extends ListView{ 
//初始可拉动Y轴方向距离 
private static final int MAX_Y_OVERSCROLL_DISTANCE = 100; 
//上下文环境 
private Context mContext; 
//实际可上下拉动Y轴上的距离 
private int mMaxYOverscrollDistance; 
public FlexiListView(Context context){ 
super(context); 
mContext = context; 
initBounceListView(); 
} 
public FlexiListView(Context context,AttributeSet attrs) { 
super(context,attrs); 
mContext = context; 
initBounceListView(); 
} 
public FlexiListView(Context context,int defStyle) { 
super(context,defStyle); 
mContext = context; 
initBounceListView(); 
} 
private void initBounceListView(){ 
final DisplayMetrics metrics = mContext.getResources().getDisplayMetrics(); 
final float density = metrics.density; 
mMaxYOverscrollDistance = (int) (density * MAX_Y_OVERSCROLL_DISTANCE); 
} 
@Override 
protected boolean overScrollBy(int deltaX,boolean isTouchEvent) { 
//实现的本质就是在这里动态改变了maxOverScrollY的值 
return super.overScrollBy(deltaX,mMaxYOverscrollDistance,isTouchEvent); 
} 
}

第三种方法，结合了手势来实现ListView的弹性效果,这里可以根据手势来进行更多的扩展,代码如下:

import android.content.Context; 
import android.graphics.Rect; 
import android.util.AttributeSet; 
import android.view.GestureDetector; 
import android.view.GestureDetector.OnGestureListener; 
import android.view.MotionEvent; 
import android.view.View; 
import android.view.animation.TranslateAnimation; 
import android.widget.ListView; 
/** 
* 具有弹性效果的ListView。主要是实现父类dispatchTouchEvent方法和OnGestureListener中onScroll方法。 
* @author E 
*/ 
public class FlexibleListView extends ListView implements OnGestureListener{ 
private Context context = null; 
private boolean outBound = false; 
private int distance; 
private int firstOut; 
public FlexibleListView(Context context,attrs); 
this.context = context; 
} 
public FlexibleListView(Context context,defStyle); 
this.context = context; 
} 
public FlexibleListView(Context context) { 
super(context); 
this.context = context; 
} 
GestureDetector lisGestureDetector = new GestureDetector(context,this); 
@Override 
public boolean dispatchTouchEvent(MotionEvent event) { 
int act = event.getAction(); 
if ((act == MotionEvent.ACTION_UP || act == MotionEvent.ACTION_CANCEL) 
&& outBound) { 
outBound = false; 
// scroll back 
} 
if (!lisGestureDetector.onTouchEvent(event)) { 
outBound = false; 
} else { 
outBound = true; 
} 
Rect rect = new Rect(); 
getLocalVisibleRect(rect); 
TranslateAnimation am = new TranslateAnimation( 0,-rect.top,0); 
am.setDuration(300); 
startAnimation(am); 
scrollTo(0,0); 
return super.dispatchTouchEvent(event); 
} 
@Override 
public boolean onDown(MotionEvent e) { 
return false; 
} 
@Override 
public void onShowPress(MotionEvent e) { 
} 
@Override 
public boolean onSingleTapUp(MotionEvent e) { 
return false; 
} 
@Override 
public boolean onScroll(MotionEvent e1,MotionEvent e2,float distanceX,float distanceY) { 
int firstPos = getFirstVisiblePosition(); 
int lastPos = getLastVisiblePosition(); 
int itemCount = getCount(); 
// outbound Top 
if (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 slide 
distance = firstOut - (int) e2.getRawY(); 
scrollTo(0,distance / 2); 
return true; 
} 
// outbound Bottom 
return false; 
} 
@Override 
public void onLongPress(MotionEvent e) { 
} 
@Override 
public boolean onFling(MotionEvent e1,float velocityX,float velocityY) { 
return false; 
} 
}

以上给大家分享了几种比较常用的方法，编程小技巧小编整理出来的，希望对大家有所帮助。