本文实例介绍的android的gallery控件是个很不错的看图控件,可以大大减轻开发者对于看图功能的开发,并且效果也很美观。本文实例中的gallery的用法,主要实现用反射机制来动态读取资源中的图片。
该实例代码运行的效果图如下:
main.xml源码如下:
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<?xml version= "1.0" encoding= "utf-8" ?> <linearlayout xmlns:android= "http://schemas.android.com/apk/res/android" android:orientation= "vertical" android:layout_width= "fill_parent" android:layout_height= "fill_parent" > <gallery android:id= "@+id/gallery" android:layout_height= "fill_parent" android:layout_width= "fill_parent" ></gallery> </linearlayout> |
java程序源码如下:
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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.graphics.bitmap; import android.graphics.bitmapfactory; import android.os.bundle; import android.view.view; import android.view.viewgroup; import android.widget.adapterview; import android.widget.baseadapter; import android.widget.gallery; import android.widget.imageview; import android.widget.adapterview.onitemclicklistener; public class testimageview extends activity { private gallery mgallery; @override public void oncreate(bundle savedinstancestate) { super .oncreate(savedinstancestate); setcontentview(r.layout.main); mgallery = (gallery)findviewbyid(r.id.gallery); try { mgallery.setadapter( new imageadapter( this )); } catch (illegalargumentexception e) { // todo auto-generated catch block e.printstacktrace(); } catch (illegalaccessexception e) { // todo auto-generated catch block e.printstacktrace(); } mgallery.setonitemclicklistener( new onitemclicklistener() { public void onitemclick(adapterview parent, view v, int position, long id) { testimageview. this .settitle(string.valueof(position)); } }); } /* * class imageadapter is used to control gallery source and operation. */ private class imageadapter extends baseadapter{ private context mcontext; private arraylist<integer> imglist= new arraylist<integer>(); private arraylist<object> imgsizes= new arraylist<object>(); public imageadapter(context c) throws illegalargumentexception, illegalaccessexception{ mcontext = c; //用反射机制来获取资源中的图片id和尺寸 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=field.getint(r.drawable. class ); //保存图片id imglist.add(index); //保存图片大小 int size[]= new int [ 2 ]; bitmap bmimg=bitmapfactory.decoderesource(getresources(),index); size[ 0 ]=bmimg.getwidth();size[ 1 ]=bmimg.getheight(); imgsizes.add(size); } } } @override public int getcount() { // todo auto-generated method stub return imglist.size(); } @override public object getitem( int position) { // todo auto-generated method stub return position; } @override public long getitemid( int position) { // todo auto-generated method stub return position; } @override public view getview( int position, view convertview, viewgroup parent) { // todo auto-generated method stub imageview i = new imageview (mcontext); //从imglist取得图片id i.setimageresource(imglist.get(position).intvalue()); i.setscaletype(imageview.scaletype.fit_xy); //从imgsizes取得图片大小 int size[]= new int [ 2 ]; size=( int []) imgsizes.get(position); i.setlayoutparams( new gallery.layoutparams(size[ 0 ], size[ 1 ])); return i; } }; } |