Gallery

package com.example.android_23;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;

public class MainActivity extends Activity {
 private Gallery gallery;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  gallery = (Gallery) findViewById(R.id.gallery1);
  gallery.setAdapter(new GalleryAdapter());
  
  gallery.setOnItemSelectedListener(new OnItemSelectedListener() {

   @Override
   public void onItemSelected(AdapterView<?> arg0, View arg1,
     int arg2, long arg3) {
    System.out.println("您点击的是："+arg2);
    
   }

   @Override
   public void onNothingSelected(AdapterView<?> arg0) {
    // TODO 自动生成的方法存根
    
   }
  });
 }
 
 class GalleryAdapter extends BaseAdapter{
  
  private int[] images = {R.drawable.gallery_photo_1,
    R.drawable.gallery_photo_2,
    R.drawable.gallery_photo_3,
    R.drawable.gallery_photo_4,
    R.drawable.gallery_photo_5,
    R.drawable.gallery_photo_6,
    R.drawable.gallery_photo_7,
    R.drawable.gallery_photo_8};

  @Override
  public int getCount() {
   return images.length;
  }

  @Override
  public Object getItem(int position) {
   return null;
  }

  @Override
  public long getItemId(int position) {
   return position;
  }

  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
   ImageView iv = null;
   if(convertView==null){
    convertView = new ImageView(MainActivity.this);
   }
   iv = (ImageView)convertView;
   iv.setImageResource(images[position]);
   
   return iv;
  }
 }
}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <Gallery
        android:id="@+id/gallery1"
        android:layout_width="match_parent"
        android:layout_height="500dp"
        />

</RelativeLayout>