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Android 自定义弹性ListView控件实例代码(三种方法)

2019年07月24日  | 移动技术网IT编程  | 我要评论

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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, attrs, 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, attributeset attrs, int defstyle) { 
super(context, attrs, 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, int deltay, int scrollx, int scrolly, int scrollrangex, 
int scrollrangey, int maxoverscrollx, int maxoverscrolly, boolean istouchevent) { 
//实现的本质就是在这里动态改变了maxoverscrolly的值 
return super.overscrollby(deltax, deltay, scrollx, scrolly, scrollrangex, scrollrangey, maxoverscrollx, 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, attributeset attrs) { 
super(context, attrs); 
this.context = context; 
} 
public flexiblelistview(context context, attributeset attrs, int defstyle) { 
super(context, attrs, 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, 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, motionevent e2, float velocityx, 
float velocityy) { 
return false; 
} 
}

以上给大家分享了几种比较常用的方法，移动技术网小编整理出来的，希望对大家有所帮助。

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