继上一篇介绍了如何使用gallery控件之后，本文就来讲一下gallery 与imageswitcher的结合使用。本文所述实例代码将实现一个简单的浏览图片的功能。
先贴出程序运行截图如下：
除了gallery可以拖拉切换图片，我在imageswitcher控件加入了setontouchlistener事件实现，使得imageswitcher也可以在拖拉中切换图片。本例子依然使用java的反射机制来自动读取资源中的图片。
main.xml的源码如下:
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<?xml version="1.0" encoding="utf-8"?>
<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<imageswitcher android:id="@+id/switcher"
android:layout_width="match_parent" android:layout_height="match_parent"/>
<gallery android:id="@+id/gallery"
android:background="#55000000"
android:layout_width="match_parent"
android:layout_alignparentbottom="true"
android:layout_alignparentleft="true"
android:gravity="center_vertical"
android:spacing="16dp" android:layout_height="100dp"/>
</relativelayout>
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java程序的源码如下:
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package com.testimageview;
import java.lang.reflect.field;
import java.util.arraylist;
import android.app.activity;
import android.content.context;
import android.os.bundle;
import android.view.motionevent;
import android.view.view;
import android.view.view.ontouchlistener;
import android.view.viewgroup;
import android.view.animation.animationutils;
import android.widget.adapterview;
import android.widget.baseadapter;
import android.widget.gallery;
import android.widget.imageswitcher;
import android.widget.imageview;
import android.widget.adapterview.onitemselectedlistener;
import android.widget.gallery.layoutparams;
import android.widget.viewswitcher.viewfactory;
public class testimageview extends activity implements viewfactory {
private imageswitcher is;
private gallery gallery;
private int downx,upx;
private arraylist<integer> imglist=new arraylist<integer>();//图像id
@override
protected void oncreate(bundle savedinstancestate) {
// todo auto-generated method stub
super.oncreate(savedinstancestate);
setcontentview(r.layout.main);
//用反射机制来获取资源中的图片id
field[] fields = r.drawable.class.getdeclaredfields();
for (field field : fields)
{
if (!"icon".equals(field.getname()))//除了icon之外的图片
{
int index = 0;
try {
index = field.getint(r.drawable.class);
} catch (illegalargumentexception e) {
// todo auto-generated catch block
e.printstacktrace();
} catch (illegalaccessexception e) {
// todo auto-generated catch block
e.printstacktrace();
}
//保存图片id
imglist.add(index);
}
}
//设置imageswitcher控件
is = (imageswitcher) findviewbyid(r.id.switcher);
is.setfactory(this);
is.setinanimation(animationutils.loadanimation(this,
android.r.anim.fade_in));
is.setoutanimation(animationutils.loadanimation(this,
android.r.anim.fade_out));
is.setontouchlistener(new ontouchlistener(){
/*
* 在imageswitcher控件上滑动可以切换图片
*/
@override
public boolean ontouch(view v, motionevent event) {
if(event.getaction()==motionevent.action_down)
{
downx=(int) event.getx();//取得按下时的坐标
return true;
}
else if(event.getaction()==motionevent.action_up)
{
upx=(int) event.getx();//取得松开时的坐标
int index=0;
if(upx-downx>100)//从左拖到右，即看前一张
{
//如果是第一，则去到尾部
if(gallery.getselecteditemposition()==0)
index=gallery.getcount()-1;
else
index=gallery.getselecteditemposition()-1;
}
else if(downx-upx>100)//从右拖到左，即看后一张
{
//如果是最后，则去到第一
if(gallery.getselecteditemposition()==(gallery.getcount()-1))
index=0;
else
index=gallery.getselecteditemposition()+1;
}
//改变gallery图片所选，自动触发imageswitcher的setonitemselectedlistener
gallery.setselection(index, true);
return true;
}
return false;
}
});
//设置gallery控件
gallery = (gallery) findviewbyid(r.id.gallery);
gallery.setadapter(new imageadapter(this));
gallery.setonitemselectedlistener(new onitemselectedlistener(){
@override
public void onitemselected(adapterview<?> arg0, view arg1,
int position, long arg3) {
is.setimageresource(imglist.get(position));
}
@override
public void onnothingselected(adapterview<?> arg0) {
// todo auto-generated method stub
}
});
}
//设置imgaeswitcher
@override
public view makeview() {
imageview i = new imageview(this);
i.setbackgroundcolor(0xff000000);
i.setscaletype(imageview.scaletype.center);//居中
i.setlayoutparams(new imageswitcher.layoutparams(//自适应图片大小
layoutparams.fill_parent, layoutparams.fill_parent));
return i;
}
public class imageadapter extends baseadapter {
public imageadapter(context c) {
mcontext = c;
}
public int getcount() {
return imglist.size();
}
public object getitem(int position) {
return position;
}
public long getitemid(int position) {
return position;
}
public view getview(int position, view convertview, viewgroup parent) {
imageview i = new imageview(mcontext);
i.setimageresource(imglist.get(position));
i.setadjustviewbounds(true);
i.setlayoutparams(new gallery.layoutparams(
layoutparams.wrap_content, layoutparams.wrap_content));
return i;
}
private context mcontext;
}
}
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