当用户选中一张图片之后，可以直接将其显示在正中央。
要实现显示图片的切换，那么就要依靠ImageSwitchar类完成。
在main.xml中
<?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"
android:gravity="bottom">
<ImageSwitcher
android:id="@+id/myImageSwitcher"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
/>
<Gallery
android:id="@+id/myGallery"
android:gravity="center_vertical"
android:spacing="3px"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
</LinearLayout>
在grid_layout.xml中
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<ImageView
android:id="@+id/img"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="center"/>
</LinearLayout>
在MyGalleryDemo.java程序中
package org.lxh.demo;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Gallery;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.SimpleAdapter;
import android.widget.ViewSwitcher.ViewFactory;
public class MyGalleryDemo extends Activity {
private Gallery gallery = null;
private SimpleAdapter simpleAdapter = null ;
private List<Map<String,Integer>> list = new ArrayList<Map<String,Integer>>() ;
private ImageSwitcher myImageSwitcher = null ;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
super.setContentView(R.layout.main);
this.initAdapter() ;
this.gallery = (Gallery) super.findViewById(R.id.myGallery);
this.myImageSwitcher = (ImageSwitcher) super.findViewById(R.id.myImageSwitcher) ;
this.gallery.setAdapter(this.simpleAdapter) ;
this.myImageSwitcher.setFactory(new ViewFactoryImpl()) ;
this.gallery.setOnItemClickListener(new OnItemClickListenerImpl()) ;
}
private void initAdapter(){
Field [] fields = R.drawable.class.getDeclaredFields() ; // 取得全部的属性
for (int x = 0; x < fields.length; x++) {
if(fields[x].getName().startsWith("ispic_")){ // 我们所需要的图片
Map<String,Integer> map = new HashMap<String,Integer>() ;
try{
map.put("img", fields[x].getInt(R.drawable.class)) ; // 必须定义好名称是img
} catch(Exception e){
}
this.list.add(map) ;
}
}
this.simpleAdapter = new SimpleAdapter(this,
this.list,
R.layout.grid_layout, new String[] { "img" },
new int[] { R.id.img });
}
private class OnItemClickListenerImpl implements OnItemClickListener {
public void onItemClick(AdapterView<?> parent, View view,
int position,
long id) {
Map<String, Integer> map = (Map<String, Integer>) parent
.getAdapter().getItem(position);
MyGalleryDemo.this.myImageSwitcher.setImageResource(map.get("img")) ;
}
}
private class ViewFactoryImpl implements ViewFactory{
public View makeView() {
ImageView img = new ImageView(MyGalleryDemo.this) ;
img.setBackgroundColor(0xFFFFFFFF) ;
img.setScaleType(ImageView.ScaleType.CENTER) ;
img.setLayoutParams(new ImageSwitcher.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
return img;
}
}
}
使用SimpleAdapter一定需要一个布局文件。