<span style="font-size:18px;"><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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <GridView
        android:id="@+id/gridview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:stretchMode="columnWidth"
        android:numColumns="4"
         />

</RelativeLayout>
</span>

<span style="font-size:18px;">package com.example.gridview;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewGroup.LayoutParams;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;

public class MainActivity extends Activity {
	private GridView gridView;// 初始化GridView
	private int images[] = { R.drawable.a1, R.drawable.a2, R.drawable.a3,
			R.drawable.a4, R.drawable.a5, R.drawable.a6, R.drawable.a7,
			R.drawable.a8, R.drawable.a9, R.drawable.a10, R.drawable.a11,
			R.drawable.a12, R.drawable.a13, R.drawable.a14, R.drawable.a15,
			R.drawable.a16 };// 图片数据

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		// 获得GridView对象
		gridView = (GridView) this.findViewById(R.id.gridview);
		// 设置Adpter
		gridView.setAdapter(new MyAdapter());
		// 设置监听事件
		gridView.setOnItemClickListener(new OnItemClickListener() {

			@Override
			public void onItemClick(AdapterView<?> adapterView, View view,
					int position, long id) {
				// TODO Auto-generated method stub
				// 为dialog设置view空间
				ImageView image = new ImageView(MainActivity.this);
				// 设置图片信息
				image.setImageResource(images[position]);
				// 设置图片的额对齐方式
				image.setScaleType(ImageView.ScaleType.CENTER);
				// 设置图片的大小
				image.setLayoutParams(new LayoutParams(
						LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
//			创建对话框
				AlertDialog.Builder builder = new AlertDialog.Builder(
					
						MainActivity.this)

						.setTitle("查看图片")
						
						.setView(image)
						
						.setIcon(android.R.drawable.btn_star_big_on)
						
						.setNegativeButton("关闭", new OnClickListener() {

							@Override
							public void onClick(DialogInterface arg0, int arg1) {
								// TODO Auto-generated method stub

							}
						});
//创建对话框
				builder.create();
//显示对话框
				builder.show();
			}
		});
	}

	class MyAdapter extends BaseAdapter {

		@Override
		public int getCount() {
			// TODO Auto-generated method stub
			return images.length;
		}

		@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 myView, ViewGroup parent) {
		
			// TODO Auto-generated method stub
//			返回imageView对象
			ImageView imageView = new ImageView(MainActivity.this);
			imageView.setImageResource(images[position]);
			imageView.setScaleType(ImageView.ScaleType.CENTER);
			return imageView;
		}
	}
}
</span>