利用LruCache为GridView异步加载大量网络图片完整示例-阿里云开发者社区

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利用LruCache为GridView异步加载大量网络图片完整示例

简介: MainActivity如下: package cc.testlrucache; import android.os.Bundle; import android.
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MainActivity如下:

package cc.testlrucache;

import android.os.Bundle;
import android.widget.GridView;
import android.app.Activity;
/**
 * Demo描述:
 * 在GridView中采用LruCache异步加载大量图片,避免OOM
 * 
 * 学习资料:
 * http://blog.csdn.net/guolin_blog/article/details/9526203
 * Thank you very much
 */

public class MainActivity extends Activity {
	private GridView mGridView;
	private GridViewAdapter mGridViewAdapter;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		init();
	}
	
	private void init(){
		mGridView = (GridView) findViewById(R.id.gridView);
		mGridViewAdapter = new GridViewAdapter(this, 0, ImagesUrl.Urls, mGridView);
		mGridView.setAdapter(mGridViewAdapter);
	}

	//取消所有的下载任务
	@Override
	protected void onDestroy() {
		super.onDestroy();
		mGridViewAdapter.cancelAllTasks();
	}

}


GridViewAdapter如下:

package cc.testlrucache;

import java.net.HttpURLConnection;
import java.net.URL;
import java.util.HashSet;
import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.support.v4.util.LruCache;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.ArrayAdapter;
import android.widget.GridView;
import android.widget.ImageView;
/**
 * LruCache的流程分析:
 * 我们从第一次进入应用的情况下开始
 * 1 依据图片的Url从LruCache缓存中取图片.
 *   若图片存在缓存中,则显示该图片;否则显示默认图片
 * 2 因为是第一次进入该界面所以会执行:
 *   loadBitmaps(firstVisibleItem, visibleItemCount);
 *   我们从loadBitmaps()方法作为切入点,继续往下梳理
 * 3 尝试从LruCache缓存中取图片.如果在显示即可,否则进入4
 * 4 开启一个异步任务下载图片.下载完成后显示图片,并且将
 *   该图片存入LruCache缓存中
 *   
 * 在停止滑动时,会调用loadBitmaps(firstVisibleItem, visibleItemCount)
 * 情况与上类似
 */
@SuppressLint("NewApi")
public class GridViewAdapter extends ArrayAdapter<String> {
	
	private GridView mGridView;
	//图片缓存类
	private LruCache<String, Bitmap> mLruCache;
	//记录所有正在下载或等待下载的任务
	private HashSet<DownloadBitmapAsyncTask> mDownloadBitmapAsyncTaskHashSet;
	//GridView中可见的第一张图片的下标
	private int mFirstVisibleItem;
	//GridView中可见的图片的数量
	private int mVisibleItemCount;
	//记录是否是第一次进入该界面
	private boolean isFirstEnterThisActivity = true;

	public GridViewAdapter(Context context, int textViewResourceId,String[] objects, GridView gridView) {
		super(context, textViewResourceId, objects);
		
		mGridView = gridView;
		mGridView.setOnScrollListener(new ScrollListenerImpl());
		
		mDownloadBitmapAsyncTaskHashSet = new HashSet<DownloadBitmapAsyncTask>();
		
		// 获取应用程序最大可用内存
		int maxMemory = (int) Runtime.getRuntime().maxMemory();
		// 设置图片缓存大小为maxMemory的1/6
		int cacheSize = maxMemory/6;
		
		mLruCache = new LruCache<String, Bitmap>(cacheSize) {
			@Override
			protected int sizeOf(String key, Bitmap bitmap) {
				return bitmap.getByteCount();
			}
		};
		
	}

	@Override
	public View getView(int position, View convertView, ViewGroup parent) {
		String url = getItem(position);
		View view;
		if (convertView == null) {
			view = LayoutInflater.from(getContext()).inflate(R.layout.gridview_item, null);
		} else {
			view = convertView;
		}
		ImageView imageView = (ImageView) view.findViewById(R.id.imageView);
		//为该ImageView设置一个Tag,防止图片错位
		imageView.setTag(url);
		//为该ImageView设置显示的图片
		setImageForImageView(url, imageView);
		return view;
	}

	/**
	 * 为ImageView设置图片(Image)
	 * 1 从缓存中获取图片
	 * 2 若图片不在缓存中则为其设置默认图片
	 */
	private void setImageForImageView(String imageUrl, ImageView imageView) {
		Bitmap bitmap = getBitmapFromLruCache(imageUrl);
		if (bitmap != null) {
			imageView.setImageBitmap(bitmap);
		} else {
			imageView.setImageResource(R.drawable.default_image);
		}
	}

	/**
	 * 将图片存储到LruCache
	 */
	public void addBitmapToLruCache(String key, Bitmap bitmap) {
		if (getBitmapFromLruCache(key) == null) {
			mLruCache.put(key, bitmap);
		}
	}

	/**
	 * 从LruCache缓存获取图片
	 */
	public Bitmap getBitmapFromLruCache(String key) {
		return mLruCache.get(key);
	}

	

   /**
    * 为GridView的item加载图片
    * 
    * @param firstVisibleItem 
    * GridView中可见的第一张图片的下标
    * 
    * @param visibleItemCount 
    * GridView中可见的图片的数量
    * 
    */
	private void loadBitmaps(int firstVisibleItem, int visibleItemCount) {
		try {
			for (int i = firstVisibleItem; i < firstVisibleItem + visibleItemCount; i++) {
				String imageUrl = ImagesUrl.Urls[i];
				Bitmap bitmap = getBitmapFromLruCache(imageUrl);
				if (bitmap == null) {
					DownloadBitmapAsyncTask downloadBitmapAsyncTask = new DownloadBitmapAsyncTask();
					mDownloadBitmapAsyncTaskHashSet.add(downloadBitmapAsyncTask);
					downloadBitmapAsyncTask.execute(imageUrl);
				} else {
					//依据Tag找到对应的ImageView显示图片
					ImageView imageView = (ImageView) mGridView.findViewWithTag(imageUrl);
					if (imageView != null && bitmap != null) {
						imageView.setImageBitmap(bitmap);
					}
				}
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	/**
	 * 取消所有正在下载或等待下载的任务
	 */
	public void cancelAllTasks() {
		if (mDownloadBitmapAsyncTaskHashSet != null) {
			for (DownloadBitmapAsyncTask task : mDownloadBitmapAsyncTaskHashSet) {
				task.cancel(false);
			}
		}
	}
	
	
	private class ScrollListenerImpl implements OnScrollListener{
	    /**
	     * 
	     * 我们的本意是通过onScrollStateChanged获知:每次GridView停止滑动时加载图片
	     * 但是存在一个特殊情况:
	     * 当第一次入应用的时候,此时并没有滑动屏幕的操作即不会调用onScrollStateChanged,但应该加载图片.
	     * 所以在此处做一个特殊的处理.
	     * 即代码:
	     * if (isFirstEnterThisActivity && visibleItemCount > 0) {
	     *      loadBitmaps(firstVisibleItem, visibleItemCount);
	     *      isFirstEnterThisActivity = false;
	     *    }
	     *    
	     * ------------------------------------------------------------
	     * 
	     * 其余的都是正常情况.
	     * 所以我们需要不断保存:firstVisibleItem和visibleItemCount
	     * 从而便于中在onScrollStateChanged()判断当停止滑动时加载图片
	     * 
	     */
		@Override
		public void onScroll(AbsListView view, int firstVisibleItem,int visibleItemCount, int totalItemCount) {
			mFirstVisibleItem = firstVisibleItem;
			mVisibleItemCount = visibleItemCount;
			if (isFirstEnterThisActivity && visibleItemCount > 0) {
				loadBitmaps(firstVisibleItem, visibleItemCount);
				isFirstEnterThisActivity = false;
			}
		}
		
		/**
		 *  GridView停止滑动时下载图片
		 *  其余情况下取消所有正在下载或者等待下载的任务
		 */
		@Override
		public void onScrollStateChanged(AbsListView view, int scrollState) {
			if (scrollState == SCROLL_STATE_IDLE) {
				loadBitmaps(mFirstVisibleItem, mVisibleItemCount);
			} else {
				cancelAllTasks();
			}
		}
		
	}

	/**
	 * 下载图片的异步任务
	 */
	class DownloadBitmapAsyncTask extends AsyncTask<String, Void, Bitmap> {
		private String imageUrl;
		@Override
		protected Bitmap doInBackground(String... params) {
			imageUrl = params[0];
			Bitmap bitmap = downloadBitmap(params[0]);
			if (bitmap != null) {
				//下载完后,将其缓存到LrcCache
				addBitmapToLruCache(params[0], bitmap);
			}
			return bitmap;
		}

		@Override
		protected void onPostExecute(Bitmap bitmap) {
			super.onPostExecute(bitmap);
			//下载完成后,找到其对应的ImageView显示图片
			ImageView imageView = (ImageView) mGridView.findViewWithTag(imageUrl);
			if (imageView != null && bitmap != null) {
				imageView.setImageBitmap(bitmap);
			}
			mDownloadBitmapAsyncTaskHashSet.remove(this);
		}
	}

	// 获取Bitmap
	private Bitmap downloadBitmap(String imageUrl) {
		Bitmap bitmap = null;
		HttpURLConnection httpURLConnection = null;
		try {
			URL url = new URL(imageUrl);
			httpURLConnection = (HttpURLConnection) url.openConnection();
			httpURLConnection.setConnectTimeout(5 * 1000);
			httpURLConnection.setReadTimeout(10 * 1000);
			httpURLConnection.setDoInput(true);
			httpURLConnection.setDoOutput(true);
			bitmap = BitmapFactory.decodeStream(httpURLConnection.getInputStream());
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if (httpURLConnection != null) {
				httpURLConnection.disconnect();
			}
		}
		return bitmap;
	}

}


ImagesUrl如下:

package cc.testlrucache;

public class ImagesUrl {

	public final static String[] Urls = new String[] {
			"https://lh6.googleusercontent.com/-55osAWw3x0Q/URquUtcFr5I/AAAAAAAAAbs/rWlj1RUKrYI/s160-c/A%252520Photographer.jpg",
			"https://lh4.googleusercontent.com/--dq8niRp7W4/URquVgmXvgI/AAAAAAAAAbs/-gnuLQfNnBA/s160-c/A%252520Song%252520of%252520Ice%252520and%252520Fire.jpg",
			"https://lh5.googleusercontent.com/-7qZeDtRKFKc/URquWZT1gOI/AAAAAAAAAbs/hqWgteyNXsg/s160-c/Another%252520Rockaway%252520Sunset.jpg",
			"https://lh3.googleusercontent.com/--L0Km39l5J8/URquXHGcdNI/AAAAAAAAAbs/3ZrSJNrSomQ/s160-c/Antelope%252520Butte.jpg",
			"https://lh6.googleusercontent.com/-8HO-4vIFnlw/URquZnsFgtI/AAAAAAAAAbs/WT8jViTF7vw/s160-c/Antelope%252520Hallway.jpg",
			"https://lh4.googleusercontent.com/-WIuWgVcU3Qw/URqubRVcj4I/AAAAAAAAAbs/YvbwgGjwdIQ/s160-c/Antelope%252520Walls.jpg",
			"https://lh6.googleusercontent.com/-UBmLbPELvoQ/URqucCdv0kI/AAAAAAAAAbs/IdNhr2VQoQs/s160-c/Apre%2525CC%252580s%252520la%252520Pluie.jpg",
			"https://lh3.googleusercontent.com/-s-AFpvgSeew/URquc6dF-JI/AAAAAAAAAbs/Mt3xNGRUd68/s160-c/Backlit%252520Cloud.jpg",
			"https://lh5.googleusercontent.com/-bvmif9a9YOQ/URquea3heHI/AAAAAAAAAbs/rcr6wyeQtAo/s160-c/Bee%252520and%252520Flower.jpg",
			"https://lh5.googleusercontent.com/-n7mdm7I7FGs/URqueT_BT-I/AAAAAAAAAbs/9MYmXlmpSAo/s160-c/Bonzai%252520Rock%252520Sunset.jpg",
			"https://lh6.googleusercontent.com/-4CN4X4t0M1k/URqufPozWzI/AAAAAAAAAbs/8wK41lg1KPs/s160-c/Caterpillar.jpg",
			"https://lh3.googleusercontent.com/-rrFnVC8xQEg/URqufdrLBaI/AAAAAAAAAbs/s69WYy_fl1E/s160-c/Chess.jpg",
			"https://lh5.googleusercontent.com/-WVpRptWH8Yw/URqugh-QmDI/AAAAAAAAAbs/E-MgBgtlUWU/s160-c/Chihuly.jpg",
			"https://lh5.googleusercontent.com/-0BDXkYmckbo/URquhKFW84I/AAAAAAAAAbs/ogQtHCTk2JQ/s160-c/Closed%252520Door.jpg",
			"https://lh3.googleusercontent.com/-PyggXXZRykM/URquh-kVvoI/AAAAAAAAAbs/hFtDwhtrHHQ/s160-c/Colorado%252520River%252520Sunset.jpg",
			"https://lh3.googleusercontent.com/-ZAs4dNZtALc/URquikvOCWI/AAAAAAAAAbs/DXz4h3dll1Y/s160-c/Colors%252520of%252520Autumn.jpg",
			"https://lh4.googleusercontent.com/-GztnWEIiMz8/URqukVCU7bI/AAAAAAAAAbs/jo2Hjv6MZ6M/s160-c/Countryside.jpg",
			"https://lh4.googleusercontent.com/-bEg9EZ9QoiM/URquklz3FGI/AAAAAAAAAbs/UUuv8Ac2BaE/s160-c/Death%252520Valley%252520-%252520Dunes.jpg",
			"https://lh6.googleusercontent.com/-ijQJ8W68tEE/URqulGkvFEI/AAAAAAAAAbs/zPXvIwi_rFw/s160-c/Delicate%252520Arch.jpg",
			"https://lh5.googleusercontent.com/-Oh8mMy2ieng/URqullDwehI/AAAAAAAAAbs/TbdeEfsaIZY/s160-c/Despair.jpg",
			"https://lh5.googleusercontent.com/-gl0y4UiAOlk/URqumC_KjBI/AAAAAAAAAbs/PM1eT7dn4oo/s160-c/Eagle%252520Fall%252520Sunrise.jpg",
			"https://lh3.googleusercontent.com/-hYYHd2_vXPQ/URqumtJa9eI/AAAAAAAAAbs/wAalXVkbSh0/s160-c/Electric%252520Storm.jpg",
			"https://lh5.googleusercontent.com/-PyY_yiyjPTo/URqunUOhHFI/AAAAAAAAAbs/azZoULNuJXc/s160-c/False%252520Kiva.jpg",
			"https://lh6.googleusercontent.com/-PYvLVdvXywk/URqunwd8hfI/AAAAAAAAAbs/qiMwgkFvf6I/s160-c/Fitzgerald%252520Streaks.jpg",
			"https://lh4.googleusercontent.com/-KIR_UobIIqY/URquoCZ9SlI/AAAAAAAAAbs/Y4d4q8sXu4c/s160-c/Foggy%252520Sunset.jpg",
			"https://lh6.googleusercontent.com/-9lzOk_OWZH0/URquoo4xYoI/AAAAAAAAAbs/AwgzHtNVCwU/s160-c/Frantic.jpg",
			"https://lh3.googleusercontent.com/-0X3JNaKaz48/URqupH78wpI/AAAAAAAAAbs/lHXxu_zbH8s/s160-c/Golden%252520Gate%252520Afternoon.jpg",
			"https://lh6.googleusercontent.com/-95sb5ag7ABc/URqupl95RDI/AAAAAAAAAbs/g73R20iVTRA/s160-c/Golden%252520Gate%252520Fog.jpg",
			"https://lh3.googleusercontent.com/-JB9v6rtgHhk/URqup21F-zI/AAAAAAAAAbs/64Fb8qMZWXk/s160-c/Golden%252520Grass.jpg",
			"https://lh4.googleusercontent.com/-EIBGfnuLtII/URquqVHwaRI/AAAAAAAAAbs/FA4McV2u8VE/s160-c/Grand%252520Teton.jpg",
			"https://lh4.googleusercontent.com/-WoMxZvmN9nY/URquq1v2AoI/AAAAAAAAAbs/grj5uMhL6NA/s160-c/Grass%252520Closeup.jpg",
			"https://lh3.googleusercontent.com/-6hZiEHXx64Q/URqurxvNdqI/AAAAAAAAAbs/kWMXM3o5OVI/s160-c/Green%252520Grass.jpg",
			"https://lh5.googleusercontent.com/-6LVb9OXtQ60/URquteBFuKI/AAAAAAAAAbs/4F4kRgecwFs/s160-c/Hanging%252520Leaf.jpg",
			"https://lh4.googleusercontent.com/-zAvf__52ONk/URqutT_IuxI/AAAAAAAAAbs/D_bcuc0thoU/s160-c/Highway%2525201.jpg",
			"https://lh6.googleusercontent.com/-H4SrUg615rA/URquuL27fXI/AAAAAAAAAbs/4aEqJfiMsOU/s160-c/Horseshoe%252520Bend%252520Sunset.jpg",
			"https://lh4.googleusercontent.com/-JhFi4fb_Pqw/URquuX-QXbI/AAAAAAAAAbs/IXpYUxuweYM/s160-c/Horseshoe%252520Bend.jpg",
			"https://lh5.googleusercontent.com/-UGgssvFRJ7g/URquueyJzGI/AAAAAAAAAbs/yYIBlLT0toM/s160-c/Into%252520the%252520Blue.jpg",
			"https://lh3.googleusercontent.com/-CH7KoupI7uI/URquu0FF__I/AAAAAAAAAbs/R7GDmI7v_G0/s160-c/Jelly%252520Fish%2525202.jpg",
			"https://lh4.googleusercontent.com/-pwuuw6yhg8U/URquvPxR3FI/AAAAAAAAAbs/VNGk6f-tsGE/s160-c/Jelly%252520Fish%2525203.jpg",
			"https://lh5.googleusercontent.com/-GoUQVw1fnFw/URquv6xbC0I/AAAAAAAAAbs/zEUVTQQ43Zc/s160-c/Kauai.jpg",
			"https://lh6.googleusercontent.com/-8QdYYQEpYjw/URquwvdh88I/AAAAAAAAAbs/cktDy-ysfHo/s160-c/Kyoto%252520Sunset.jpg",
			"https://lh4.googleusercontent.com/-vPeekyDjOE0/URquwzJ28qI/AAAAAAAAAbs/qxcyXULsZrg/s160-c/Lake%252520Tahoe%252520Colors.jpg",
			"https://lh4.googleusercontent.com/-xBPxWpD4yxU/URquxWHk8AI/AAAAAAAAAbs/ARDPeDYPiMY/s160-c/Lava%252520from%252520the%252520Sky.jpg",
			"https://lh3.googleusercontent.com/-897VXrJB6RE/URquxxxd-5I/AAAAAAAAAbs/j-Cz4T4YvIw/s160-c/Leica%25252050mm%252520Summilux.jpg",
			"https://lh5.googleusercontent.com/-qSJ4D4iXzGo/URquyDWiJ1I/AAAAAAAAAbs/k2pBXeWehOA/s160-c/Leica%25252050mm%252520Summilux.jpg",
			"https://lh6.googleusercontent.com/-dwlPg83vzLg/URquylTVuFI/AAAAAAAAAbs/G6SyQ8b4YsI/s160-c/Leica%252520M8%252520%252528Front%252529.jpg",
			"https://lh3.googleusercontent.com/-R3_EYAyJvfk/URquzQBv8eI/AAAAAAAAAbs/b9xhpUM3pEI/s160-c/Light%252520to%252520Sand.jpg",
			"https://lh3.googleusercontent.com/-fHY5h67QPi0/URqu0Cp4J1I/AAAAAAAAAbs/0lG6m94Z6vM/s160-c/Little%252520Bit%252520of%252520Paradise.jpg",
			"https://lh5.googleusercontent.com/-TzF_LwrCnRM/URqu0RddPOI/AAAAAAAAAbs/gaj2dLiuX0s/s160-c/Lone%252520Pine%252520Sunset.jpg",
			"https://lh3.googleusercontent.com/-4HdpJ4_DXU4/URqu046dJ9I/AAAAAAAAAbs/eBOodtk2_uk/s160-c/Lonely%252520Rock.jpg",
			"https://lh6.googleusercontent.com/-erbF--z-W4s/URqu1ajSLkI/AAAAAAAAAbs/xjDCDO1INzM/s160-c/Longue%252520Vue.jpg",
			"https://lh6.googleusercontent.com/-0CXJRdJaqvc/URqu1opNZNI/AAAAAAAAAbs/PFB2oPUU7Lk/s160-c/Look%252520Me%252520in%252520the%252520Eye.jpg",
			"https://lh3.googleusercontent.com/-D_5lNxnDN6g/URqu2Tk7HVI/AAAAAAAAAbs/p0ddca9W__Y/s160-c/Lost%252520in%252520a%252520Field.jpg",
			"https://lh6.googleusercontent.com/-flsqwMrIk2Q/URqu24PcmjI/AAAAAAAAAbs/5ocIH85XofM/s160-c/Marshall%252520Beach%252520Sunset.jpg",
			"https://lh4.googleusercontent.com/-Y4lgryEVTmU/URqu28kG3gI/AAAAAAAAAbs/OjXpekqtbJ4/s160-c/Mono%252520Lake%252520Blue.jpg",
			"https://lh4.googleusercontent.com/-AaHAJPmcGYA/URqu3PIldHI/AAAAAAAAAbs/lcTqk1SIcRs/s160-c/Monument%252520Valley%252520Overlook.jpg",
			"https://lh4.googleusercontent.com/-vKxfdQ83dQA/URqu31Yq_BI/AAAAAAAAAbs/OUoGk_2AyfM/s160-c/Moving%252520Rock.jpg",
			"https://lh5.googleusercontent.com/-CG62QiPpWXg/URqu4ia4vRI/AAAAAAAAAbs/0YOdqLAlcAc/s160-c/Napali%252520Coast.jpg",
			"https://lh6.googleusercontent.com/-wdGrP5PMmJQ/URqu5PZvn7I/AAAAAAAAAbs/m0abEcdPXe4/s160-c/One%252520Wheel.jpg",
			"https://lh6.googleusercontent.com/-6WS5DoCGuOA/URqu5qx1UgI/AAAAAAAAAbs/giMw2ixPvrY/s160-c/Open%252520Sky.jpg",
			"https://lh6.googleusercontent.com/-u8EHKj8G8GQ/URqu55sM6yI/AAAAAAAAAbs/lIXX_GlTdmI/s160-c/Orange%252520Sunset.jpg",
			"https://lh6.googleusercontent.com/-74Z5qj4bTDE/URqu6LSrJrI/AAAAAAAAAbs/XzmVkw90szQ/s160-c/Orchid.jpg",
			"https://lh6.googleusercontent.com/-lEQE4h6TePE/URqu6t_lSkI/AAAAAAAAAbs/zvGYKOea_qY/s160-c/Over%252520there.jpg",
			"https://lh5.googleusercontent.com/-cauH-53JH2M/URqu66v_USI/AAAAAAAAAbs/EucwwqclfKQ/s160-c/Plumes.jpg",
			"https://lh3.googleusercontent.com/-eDLT2jHDoy4/URqu7axzkAI/AAAAAAAAAbs/iVZE-xJ7lZs/s160-c/Rainbokeh.jpg",
			"https://lh5.googleusercontent.com/-j1NLqEFIyco/URqu8L1CGcI/AAAAAAAAAbs/aqZkgX66zlI/s160-c/Rainbow.jpg",
			"https://lh5.googleusercontent.com/-DRnqmK0t4VU/URqu8XYN9yI/AAAAAAAAAbs/LgvF_592WLU/s160-c/Rice%252520Fields.jpg",
			"https://lh3.googleusercontent.com/-hwh1v3EOGcQ/URqu8qOaKwI/AAAAAAAAAbs/IljRJRnbJGw/s160-c/Rockaway%252520Fire%252520Sky.jpg",
			"https://lh5.googleusercontent.com/-wjV6FQk7tlk/URqu9jCQ8sI/AAAAAAAAAbs/RyYUpdo-c9o/s160-c/Rockaway%252520Flow.jpg",
			"https://lh6.googleusercontent.com/-6cAXNfo7D20/URqu-BdzgPI/AAAAAAAAAbs/OmsYllzJqwo/s160-c/Rockaway%252520Sunset%252520Sky.jpg",
			"https://lh3.googleusercontent.com/-sl8fpGPS-RE/URqu_BOkfgI/AAAAAAAAAbs/Dg2Fv-JxOeg/s160-c/Russian%252520Ridge%252520Sunset.jpg",
			"https://lh6.googleusercontent.com/-gVtY36mMBIg/URqu_q91lkI/AAAAAAAAAbs/3CiFMBcy5MA/s160-c/Rust%252520Knot.jpg",
			"https://lh6.googleusercontent.com/-GHeImuHqJBE/URqu_FKfVLI/AAAAAAAAAbs/axuEJeqam7Q/s160-c/Sailing%252520Stones.jpg",
			"https://lh3.googleusercontent.com/-hBbYZjTOwGc/URqu_ycpIrI/AAAAAAAAAbs/nAdJUXnGJYE/s160-c/Seahorse.jpg",
			"https://lh3.googleusercontent.com/-Iwi6-i6IexY/URqvAYZHsVI/AAAAAAAAAbs/5ETWl4qXsFE/s160-c/Shinjuku%252520Street.jpg",
			"https://lh6.googleusercontent.com/-amhnySTM_MY/URqvAlb5KoI/AAAAAAAAAbs/pFCFgzlKsn0/s160-c/Sierra%252520Heavens.jpg",
			"https://lh5.googleusercontent.com/-dJgjepFrYSo/URqvBVJZrAI/AAAAAAAAAbs/v-F5QWpYO6s/s160-c/Sierra%252520Sunset.jpg",
			"https://lh4.googleusercontent.com/-Z4zGiC5nWdc/URqvBdEwivI/AAAAAAAAAbs/ZRZR1VJ84QA/s160-c/Sin%252520Lights.jpg",
			"https://lh4.googleusercontent.com/-_0cYiWW8ccY/URqvBz3iM4I/AAAAAAAAAbs/9N_Wq8MhLTY/s160-c/Starry%252520Lake.jpg",
			"https://lh3.googleusercontent.com/-A9LMoRyuQUA/URqvCYx_JoI/AAAAAAAAAbs/s7sde1Bz9cI/s160-c/Starry%252520Night.jpg",
			"https://lh3.googleusercontent.com/-KtLJ3k858eY/URqvC_2h_bI/AAAAAAAAAbs/zzEBImwDA_g/s160-c/Stream.jpg",
			"https://lh5.googleusercontent.com/-dFB7Lad6RcA/URqvDUftwWI/AAAAAAAAAbs/BrhoUtXTN7o/s160-c/Strip%252520Sunset.jpg",
			"https://lh5.googleusercontent.com/-at6apgFiN20/URqvDyffUZI/AAAAAAAAAbs/clABCx171bE/s160-c/Sunset%252520Hills.jpg",
			"https://lh4.googleusercontent.com/-7-EHhtQthII/URqvEYTk4vI/AAAAAAAAAbs/QSJZoB3YjVg/s160-c/Tenaya%252520Lake%2525202.jpg",
			"https://lh6.googleusercontent.com/-8MrjV_a-Pok/URqvFC5repI/AAAAAAAAAbs/9inKTg9fbCE/s160-c/Tenaya%252520Lake.jpg",
			"https://lh5.googleusercontent.com/-B1HW-z4zwao/URqvFWYRwUI/AAAAAAAAAbs/8Peli53Bs8I/s160-c/The%252520Cave%252520BW.jpg",
			"https://lh3.googleusercontent.com/-PO4E-xZKAnQ/URqvGRqjYkI/AAAAAAAAAbs/42nyADFsXag/s160-c/The%252520Fisherman.jpg",
			"https://lh4.googleusercontent.com/-iLyZlzfdy7s/URqvG0YScdI/AAAAAAAAAbs/1J9eDKmkXtk/s160-c/The%252520Night%252520is%252520Coming.jpg",
			"https://lh6.googleusercontent.com/-G-k7YkkUco0/URqvHhah6fI/AAAAAAAAAbs/_taQQG7t0vo/s160-c/The%252520Road.jpg",
			"https://lh6.googleusercontent.com/-h-ALJt7kSus/URqvIThqYfI/AAAAAAAAAbs/ejiv35olWS8/s160-c/Tokyo%252520Heights.jpg",
			"https://lh5.googleusercontent.com/-Hy9k-TbS7xg/URqvIjQMOxI/AAAAAAAAAbs/RSpmmOATSkg/s160-c/Tokyo%252520Highway.jpg",
			"https://lh6.googleusercontent.com/-83oOvMb4OZs/URqvJL0T7lI/AAAAAAAAAbs/c5TECZ6RONM/s160-c/Tokyo%252520Smog.jpg",
			"https://lh3.googleusercontent.com/-FB-jfgREEfI/URqvJI3EXAI/AAAAAAAAAbs/XfyweiRF4v8/s160-c/Tufa%252520at%252520Night.jpg",
			"https://lh4.googleusercontent.com/-vngKD5Z1U8w/URqvJUCEgPI/AAAAAAAAAbs/ulxCMVcU6EU/s160-c/Valley%252520Sunset.jpg",
			"https://lh6.googleusercontent.com/-DOz5I2E2oMQ/URqvKMND1kI/AAAAAAAAAbs/Iqf0IsInleo/s160-c/Windmill%252520Sunrise.jpg",
			"https://lh5.googleusercontent.com/-biyiyWcJ9MU/URqvKculiAI/AAAAAAAAAbs/jyPsCplJOpE/s160-c/Windmill.jpg",
			"https://lh4.googleusercontent.com/-PDT167_xRdA/URqvK36mLcI/AAAAAAAAAbs/oi2ik9QseMI/s160-c/Windmills.jpg",
			"https://lh5.googleusercontent.com/-kI_QdYx7VlU/URqvLXCB6gI/AAAAAAAAAbs/N31vlZ6u89o/s160-c/Yet%252520Another%252520Rockaway%252520Sunset.jpg",
			"https://lh4.googleusercontent.com/-e9NHZ5k5MSs/URqvMIBZjtI/AAAAAAAAAbs/1fV810rDNfQ/s160-c/Yosemite%252520Tree.jpg", };
}


main.xml如下:

<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" >

    <GridView
        android:id="@+id/gridView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:columnWidth="90dip"
        android:gravity="center"
        android:numColumns="auto_fit"
        android:stretchMode="columnWidth"
        android:verticalSpacing="10dip"
    />

</RelativeLayout>


gridview_item.xml如下:

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

    <ImageView 
        android:id="@+id/imageView"
        android:layout_width="90dip"
        android:layout_height="90dip"
        android:src="@drawable/default_image"
        android:layout_centerInParent="true"
        />

</RelativeLayout>


 

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