android 实现简单带预览的图片浏览器

简单记录
程序结构为 activity  main.xml   cell.mxl   另外drawalbe文件夹下放置所需图片资源

主UI布局代码：

<LinearLayout xmlns:android=""
    xmlns:tools=""
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical">"


        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:id="@+id/grid01"
        android:horizontalSpacing="1pt"
        android:verticalSpacing="1pt"
        android:numColumns="4"
        android:gravity="center"
         />

        android:id="@+id/imageview"
        android:layout_width="240dp"
        android:layout_height="240dp"
        android:layout_gravity="center_horizontal"
        android:contentDescription="@string/app_name

Activity代码

package com.gridviewdemo;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;



import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.SimpleAdapter;

public class MainActivity extends Activity {

    GridView grid;
    ImageView imageview;
    int [] imageIds =new int []{
            R.drawable.img1,R.drawable.img2,
            R.drawable.img3,R.drawable.img4,
            R.drawable.img5,R.drawable.img6,
            R.drawable.img6,R.drawable.ic_launcher
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        List<Map<String,Object>> listitems =new ArrayList<Map<String,Object>>();
        for(int i=0;i<imageIds.length;i++){
            Map<String,Object> listitem =new HashMap<String,Object>();
            listitem.put("image", imageIds[i]);
            listitems.add(listitem);
        }

        /**
        * 本程序主要内容也是下面小段代码,所做的就是为网格布局构建一个Adapter
        */
        imageview = (ImageView)findViewById(R.id.imageview);
        SimpleAdapter simpleAdapter =new SimpleAdapter(this,
                                                       listitems,
                                                       R.layout.cell,
                 new String[]{"image"},
                 new int []{R.id.image1});
        grid =(GridView)findViewById(R.id.grid01);
        grid.setAdapter(simpleAdapter);

        imageview.setImageResource(imageIds[7]);//默认显示的图片

        grid.setOnItemClickListener(new OnItemClickListener(){

            @Override
            public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                    long arg3) {
                // TODO Auto-generated method stub
                imageview.setImageResource(imageIds[arg2]);

            }

        });


    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

另外Adapter所需的cell.xml文件内容为

<?xml version="1.0" encoding="UTF-8"?>
<LinearLayout xmlns:android=""
    android:orientation="horizontal"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:gravity="center_horizontal"
    android:padding="2pt"
    >
<ImageView
    android:id="@+id/image1"
    android:layout_width="50dp"
    android:layout_height="50dp"
    />
</LinearLayout>

运行效果为：