文章标题：Android常见组件Gallery的用法

<Gallery
android:id="@+id/gallery1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:spacing="5px"
android:unselectedAlpha="0.6"
/>

package com.example.gallery;

import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.content.res.TypedArray;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;
import android.widget.Toast;
import android.os.Build;

public class MainActivity extends Activity {
private int[] imageId=new int[]{
R.drawable.bj,      R.drawable.bj1, R.drawable.bj11,R.drawable.bj12
};
Gallery gallery;
protected char[] position;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Gallery gallery=(Gallery) findViewById(R.id.gallery1);
//将适配器与Gallery关联
gallery.setAdapter(adapter);
//让中间的图片选中
gallery.setSelection(imageId.length/2);
gallery.setOnItemClickListener(new OnItemClickListener(){

@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
long arg3) {
// TODO Auto-generated method stub
Toast.makeText(MainActivity.this, "你选择了第"+String.valueOf(position)+"张图片",
Toast.LENGTH_SHORT).show();
}
});
}
BaseAdapter adapter=new BaseAdapter() {

@Override
public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageview;
if(convertView == null){
//创建ImageView的对象
imageview =new ImageView(MainActivity.this);
imageview .setScaleType(ImageView.ScaleType.FIT_XY);
//设置缩放方式
imageview .setLayoutParams(new Gallery.LayoutParams(180,135));
TypedArray typedArray=obtainStyledAttributes(R.styleable.Gallery);
imageview.setBackgroundResource(typedArray.getResourceId(R.styleable.Gallery_android_galleryItemBackground,
0));
//设置ImageView的内边距
imageview .setPadding(10, 0, 10, 0);

}else{

imageview =(ImageView) convertView;
}
//为ImageView设置要显示的图片
imageview.setImageResource(imageId[position]);
//返回ImageView
return imageview;
}
//获得当前选项的ID
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
//获得当前的选项
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return position;
}
//获得数量
@Override
public int getCount() {
// TODO Auto-generated method stub
return imageId.length;
}
};
}