Android UI-开源框架ImageLoader的完美例子

Android开源框架ImageLoader的完美例子

2013年8月19日开源框架之Universal_Image_Loader学习

很多人都在讨论如何让图片能在异步加载更加流畅，可以显示大量图片，在拖动ListView的时候不会出现卡的现象。关于ImageLoader这个开源框架的使用有很多网友都介绍过，不过还不够清楚，这里有一个关于这个开源项目的完美例子，ListView的图片加载、GridView的图片加载、ViewPager的图片加载、Gallery画廊的图片加载、Widget的使用。很完善的一个例子，在这里我把所有界面效果做出博客分享出来，需要源码的朋友到我的资源页下载

下载地址：http://download.csdn.net/detail/wwj_748/5975847

要使用ImageLoader就要到这里下载jar包：

https://github.com/nostra13/Android-Universal-Image-Loader

然后导入项目中去就行了

项目文档结构图：

从界面说起，界面本身是没什么好说的，就是如何在xml当中进行定义罢了

有以下这么多个布局文件

一个一个来看呗

首先是这样的效果

这个在Android4.2.2比较好看，在Android2.3.3就显得比较挫。

/2013.8.19_Universal_Image_Loader_Demo/res/layout/ac_home.xml

列表异步加载图片效果

/2013.8.19_Universal_Image_Loader_Demo/res/layout/ac_image_list.xml

/2013.8.19_Universal_Image_Loader_Demo/res/layout/ item_list_image.xml

GridView异步加载图片显示

/2013.8.19_Universal_Image_Loader_Demo/res/layout/ac_image_grid.xml

/2013.8.19_Universal_Image_Loader_Demo/res/layout/item_grid_image.xml

ViewPager异步加载图片显示

/2013.8.19_Universal_Image_Loader_Demo/res/layout/ac_image_pager.xml

/2013.8.19_Universal_Image_Loader_Demo/res/layout/ item_pager_image.xml

Gallery画廊异步加载图片显示

/2013.8.19_Universal_Image_Loader_Demo/res/layout/ac_image_gallery.xml

/2013.8.19_Universal_Image_Loader_Demo/res/layout/item_gallery_image.xml

还有一个就是桌面小部件

以上只是布局文件，没有什么可以说，具体Activity代码实现如下：

先是这个：

/2013.8.19_Universal_Image_Loader_Demo/src/com/nostra13/example/universalimageloader/HomeActivity.java

主界面Activity代码

/*******************************************************************************
 * Copyright 2011-2013 Sergey Tarasevich
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
package com.nostra13.example.universalimageloader;

import static com.nostra13.example.universalimageloader.Constants.IMAGES;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;

import com.nostra13.example.universalimageloader.Constants.Extra;
import com.nostra13.universalimageloader.utils.L;

/**
 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
 */
public class HomeActivity extends BaseActivity {

	private static final String TEST_FILE_NAME = "Universal Image Loader @#&=+-_.,!()~'%20.png";

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.ac_home);

		// 定义文件对象，目录：/mnt/sdcard, 文件名:TEST_FILE_NAME
		File testImageOnSdCard = new File("/mnt/sdcard", TEST_FILE_NAME);
		if (!testImageOnSdCard.exists()) {	// 如果文件不存在
			// 把文件复制到SD卡
			copyTestImageToSdCard(testImageOnSdCard);
		}
	}

	// 点击进入ListView展示界面
	public void onImageListClick(View view) {
		Intent intent = new Intent(this, ImageListActivity.class);
		intent.putExtra(Extra.IMAGES, IMAGES);
		startActivity(intent);
	}

	// 点击进入GridView展示界面
	public void onImageGridClick(View view) {
		Intent intent = new Intent(this, ImageGridActivity.class);
		intent.putExtra(Extra.IMAGES, IMAGES);
		startActivity(intent);
	}

	// 点击进入ViewPager展示界面
	public void onImagePagerClick(View view) {
		Intent intent = new Intent(this, ImagePagerActivity.class);
		intent.putExtra(Extra.IMAGES, IMAGES);
		startActivity(intent);
	}

	// 点击进入画廊展示界面
	public void onImageGalleryClick(View view) {
		Intent intent = new Intent(this, ImageGalleryActivity.class);
		intent.putExtra(Extra.IMAGES, IMAGES);
		startActivity(intent);
	}

	@Override
	public void onBackPressed() {
		imageLoader.stop();		// 停止加载图片
		super.onBackPressed();
	}

	/**
	 * 开一个线程把assert目录下的图片复制到SD卡目录下
	 * @param testImageOnSdCard
	 */
	private void copyTestImageToSdCard(final File testImageOnSdCard) {
		new Thread(new Runnable() {
			@Override
			public void run() {
				try {
					InputStream is = getAssets().open(TEST_FILE_NAME);
					FileOutputStream fos = new FileOutputStream(testImageOnSdCard);
					byte[] buffer = new byte[8192];
					int read;
					try {
						while ((read = is.read(buffer)) != -1) {
							fos.write(buffer, 0, read);	// 写入输出流
						}
					} finally {
						fos.flush();		// 写入SD卡
						fos.close();		// 关闭输出流
						is.close();			// 关闭输入流
					}
				} catch (IOException e) {
					L.w("Can't copy test image onto SD card");
				}
			}
		}).start();		// 启动线程
	}
}

/2013.8.19_Universal_Image_Loader_Demo/src/com/nostra13/example/universalimageloader/ BaseActivity.java

/*******************************************************************************
 * Copyright 2011-2013 Sergey Tarasevich
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
package com.nostra13.example.universalimageloader;

import android.app.Activity;
import android.view.Menu;
import android.view.MenuItem;

import com.nostra13.universalimageloader.core.ImageLoader;

/**
 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
 */
public abstract class BaseActivity extends Activity {

	protected ImageLoader imageLoader = ImageLoader.getInstance();

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// 加载菜单
		getMenuInflater().inflate(R.menu.main_menu, menu);
		return true;
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
		switch (item.getItemId()) {
			case R.id.item_clear_memory_cache:
				imageLoader.clearMemoryCache();		// 清除内存缓存
				return true;
			case R.id.item_clear_disc_cache:
				imageLoader.clearDiscCache();		// 清除SD卡中的缓存
				return true;
			default:
				return false;
		}
	}
}

/2013.8.19_Universal_Image_Loader_Demo/src/com/nostra13/example/universalimageloader/AbsListViewBaseActivity.java

/*******************************************************************************
 * Copyright 2011-2013 Sergey Tarasevich
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
package com.nostra13.example.universalimageloader;

import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.AbsListView;

import com.nostra13.universalimageloader.core.assist.PauseOnScrollListener;

/**
 * 
 * 
 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
 */
public class AbsListViewBaseActivity extends BaseActivity {

	protected static final String STATE_PAUSE_ON_SCROLL = "STATE_PAUSE_ON_SCROLL";
	protected static final String STATE_PAUSE_ON_FLING = "STATE_PAUSE_ON_FLING";

	protected AbsListView listView;

	protected boolean pauseOnScroll = false;
	protected boolean pauseOnFling = true;

	@Override
	public void onRestoreInstanceState(Bundle savedInstanceState) {
		pauseOnScroll = savedInstanceState.getBoolean(STATE_PAUSE_ON_SCROLL, false);
		pauseOnFling = savedInstanceState.getBoolean(STATE_PAUSE_ON_FLING, true);
	}

	@Override
	public void onResume() {
		super.onResume();
		applyScrollListener();
	}

	private void applyScrollListener() {
		listView.setOnScrollListener(new PauseOnScrollListener(imageLoader, pauseOnScroll, pauseOnFling));
	}

	@Override
	public void onSaveInstanceState(Bundle outState) {
		outState.putBoolean(STATE_PAUSE_ON_SCROLL, pauseOnScroll);
		outState.putBoolean(STATE_PAUSE_ON_FLING, pauseOnFling);
	}

	@Override
	public boolean onPrepareOptionsMenu(Menu menu) {
		MenuItem pauseOnScrollItem = menu.findItem(R.id.item_pause_on_scroll);
		pauseOnScrollItem.setVisible(true);
		pauseOnScrollItem.setChecked(pauseOnScroll);

		MenuItem pauseOnFlingItem = menu.findItem(R.id.item_pause_on_fling);
		pauseOnFlingItem.setVisible(true);
		pauseOnFlingItem.setChecked(pauseOnFling);
		return true;
	}

	@Override
	public boolean onOptionsItemSelected(MenuItem item) {
		switch (item.getItemId()) {
			case R.id.item_pause_on_scroll:
				pauseOnScroll = !pauseOnScroll;
				item.setChecked(pauseOnScroll);
				applyScrollListener();
				return true;
			case R.id.item_pause_on_fling:
				pauseOnFling = !pauseOnFling;
				item.setChecked(pauseOnFling);
				applyScrollListener();
				return true;
			default:
				return super.onOptionsItemSelected(item);
		}
	}
}

/2013.8.19_Universal_Image_Loader_Demo/src/com/nostra13/example/universalimageloader/Constants.java

常量类代码

/*******************************************************************************
 * Copyright 2011-2013 Sergey Tarasevich
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
package com.nostra13.example.universalimageloader;

/**
 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
 * 常量类
 */
public final class Constants {

	// 一堆图片链接
	public static final String[] IMAGES = new String[] {
			// Heavy images
			"https://lh6.googleusercontent.com/-jZgveEqb6pg/T3R4kXScycI/AAAAAAAAAE0/xQ7CvpfXDzc/s1024/sample_image_01.jpg",
			"https://lh4.googleusercontent.com/-K2FMuOozxU0/T3R4lRAiBTI/AAAAAAAAAE8/a3Eh9JvnnzI/s1024/sample_image_02.jpg",
			"https://lh5.googleusercontent.com/-SCS5C646rxM/T3R4l7QB6xI/AAAAAAAAAFE/xLcuVv3CUyA/s1024/sample_image_03.jpg",
			"https://lh6.googleusercontent.com/-f0NJR6-_Thg/T3R4mNex2wI/AAAAAAAAAFI/45oug4VE8MI/s1024/sample_image_04.jpg",
			"https://lh3.googleusercontent.com/-n-xcJmiI0pg/T3R4mkSchHI/AAAAAAAAAFU/EoiNNb7kk3A/s1024/sample_image_05.jpg",
			"https://lh3.googleusercontent.com/-X43vAudm7f4/T3R4nGSChJI/AAAAAAAAAFk/3bna6D-2EE8/s1024/sample_image_06.jpg",
			"https://lh5.googleusercontent.com/-MpZneqIyjXU/T3R4nuGO1aI/AAAAAAAAAFg/r09OPjLx1ZY/s1024/sample_image_07.jpg",
			"https://lh6.googleusercontent.com/-ql3YNfdClJo/T3XvW9apmFI/AAAAAAAAAL4/_6HFDzbahc4/s1024/sample_image_08.jpg",
			"https://lh5.googleusercontent.com/-Pxa7eqF4cyc/T3R4oasvPEI/AAAAAAAAAF0/-uYDH92h8LA/s1024/sample_image_09.jpg",
			"https://lh4.googleusercontent.com/-Li-rjhFEuaI/T3R4o-VUl4I/AAAAAAAAAF8/5E5XdMnP1oE/s1024/sample_image_10.jpg",
			"https://lh5.googleusercontent.com/-_HU4fImgFhA/T3R4pPVIwWI/AAAAAAAAAGA/0RfK_Vkgth4/s1024/sample_image_11.jpg",
			"https://lh6.googleusercontent.com/-0gnNrVjwa0Y/T3R4peGYJwI/AAAAAAAAAGU/uX_9wvRPM9I/s1024/sample_image_12.jpg",
			"https://lh3.googleusercontent.com/-HBxuzALS_Zs/T3R4qERykaI/AAAAAAAAAGQ/_qQ16FaZ1q0/s1024/sample_image_13.jpg",
			"https://lh4.googleusercontent.com/-cKojDrARNjQ/T3R4qfWSGPI/AAAAAAAAAGY/MR5dnbNaPyY/s1024/sample_image_14.jpg",
			"https://lh3.googleusercontent.com/-WujkdYfcyZ8/T3R4qrIMGUI/AAAAAAAAAGk/277LIdgvnjg/s1024/sample_image_15.jpg",
			"https://lh6.googleusercontent.com/-FMHR7Vy3PgI/T3R4rOXlEKI/AAAAAAAAAGs/VeXrDNDBkaw/s1024/sample_image_16.jpg",
			"https://lh4.googleusercontent.com/-mrR0AJyNTH0/T3R4rZs6CuI/AAAAAAAAAG0/UE1wQqCOqLA/s1024/sample_image_17.jpg",
			"https://lh6.googleusercontent.com/-z77w0eh3cow/T3R4rnLn05I/AAAAAAAAAG4/BaerfWoNucU/s1024/sample_image_18.jpg",
			"https://lh5.googleusercontent.com/-aWVwh1OU5Bk/T3R4sAWw0yI/AAAAAAAAAHE/4_KAvJttFwA/s1024/sample_image_19.jpg",
			"https://lh6.googleusercontent.com/-q-js52DMnWQ/T3R4tZhY2sI/AAAAAAAAAHM/A8kjp2Ivdqg/s1024/sample_image_20.jpg",
			"https://lh5.googleusercontent.com/-_jIzvvzXKn4/T3R4t7xpdVI/AAAAAAAAAHU/7QC6eZ10jgs/s1024/sample_image_21.jpg",
			"https://lh3.googleusercontent.com/-lnGi4IMLpwU/T3R4uCMa7vI/AAAAAAAAAHc/1zgzzz6qTpk/s1024/sample_image_22.jpg",
			"https://lh5.googleusercontent.com/-fFCzKjFPsPc/T3R4u0SZPFI/AAAAAAAAAHk/sbgjzrktOK0/s1024/sample_image_23.jpg",
			"https://lh4.googleusercontent.com/-8TqoW5gBE_Y/T3R4vBS3NPI/AAAAAAAAAHs/EZYvpNsaNXk/s1024/sample_image_24.jpg",
			"https://lh6.googleusercontent.com/-gc4eQ3ySdzs/T3R4vafoA7I/AAAAAAAAAH4/yKii5P6tqDE/s1024/sample_image_25.jpg",
			"https://lh5.googleusercontent.com/--NYOPCylU7Q/T3R4vjAiWkI/AAAAAAAAAH8/IPNx5q3ptRA/s1024/sample_image_26.jpg",
			"https://lh6.googleusercontent.com/-9IJM8so4vCI/T3R4vwJO2yI/AAAAAAAAAIE/ljlr-cwuqZM/s1024/sample_image_27.jpg",
			"https://lh4.googleusercontent.com/-KW6QwOHfhBs/T3R4w0RsQiI/AAAAAAAAAIM/uEFLVgHPFCk/s1024/sample_image_28.jpg",
			"https://lh4.googleusercontent.com/-z2557Ec1ctY/T3R4x3QA2hI/AAAAAAAAAIk/9-GzPL1lTWE/s1024/sample_image_29.jpg",
			"https://lh5.googleusercontent.com/-LaKXAn4Kr1c/T3R4yc5b4lI/AAAAAAAAAIY/fMgcOVQfmD0/s1024/sample_image_30.jpg",
			"https://lh4.googleusercontent.com/-F9LRToJoQdo/T3R4yrLtyQI/AAAAAAAAAIg/ri9uUCWuRmo/s1024/sample_image_31.jpg",
			"https://lh4.googleusercontent.com/-6X-xBwP-QpI/T3R4zGVboII/AAAAAAAAAIs/zYH4PjjngY0/s1024/sample_image_32.jpg",
			"https://lh5.googleusercontent.com/-VdLRjbW4LAs/T3R4zXu3gUI/AAAAAAAAAIw/9aFp9t7mCPg/s1024/sample_image_33.jpg",
			"https://lh6.googleusercontent.com/-gL6R17_fDJU/T3R4zpIXGjI/AAAAAAAAAI8/Q2Vjx-L9X20/s1024/sample_image_34.jpg",
			"https://lh3.googleusercontent.com/-1fGH4YJXEzo/T3R40Y1B7KI/AAAAAAAAAJE/MnTsa77g-nk/s1024/sample_image_35.jpg",
			"https://lh4.googleusercontent.com/-Ql0jHSrea-A/T3R403mUfFI/AAAAAAAAAJM/qzI4SkcH9tY/s1024/sample_image_36.jpg",
			"https://lh5.googleusercontent.com/-BL5FIBR_tzI/T3R41DA0AKI/AAAAAAAAAJk/GZfeeb-SLM0/s1024/sample_image_37.jpg",
			"https://lh4.googleusercontent.com/-wF2Vc9YDutw/T3R41fR2BCI/AAAAAAAAAJc/JdU1sHdMRAk/s1024/sample_image_38.jpg",
			"https://lh6.googleusercontent.com/-ZWHiPehwjTI/T3R41zuaKCI/AAAAAAAAAJg/hR3QJ1v3REg/s1024/sample_image_39.jpg",
			// Light images
			"http://tabletpcssource.com/wp-content/uploads/2011/05/android-logo.png",
			"http://simpozia.com/pages/images/stories/windows-icon.png",
			"https://si0.twimg.com/profile_images/1135218951/gmail_profile_icon3_normal.png",
			"http://www.krify.net/wp-content/uploads/2011/09/Macromedia_Flash_dock_icon.png",
			"http://radiotray.sourceforge.net/radio.png",
			"http://www.bandwidthblog.com/wp-content/uploads/2011/11/twitter-logo.png",
			"http://weloveicons.s3.amazonaws.com/icons/100907_itunes1.png",
			"http://weloveicons.s3.amazonaws.com/icons/100929_applications.png",
			"http://www.idyllicmusic.com/index_files/get_apple-iphone.png",
			"http://www.frenchrevolutionfood.com/wp-content/uploads/2009/04/Twitter-Bird.png",
			"http://3.bp.blogspot.com/-ka5MiRGJ_S4/TdD9OoF6bmI/AAAAAAAAE8k/7ydKtptUtSg/s1600/Google_Sky%2BMaps_Android.png",
			"http://www.desiredsoft.com/images/icon_webhosting.png",
			"http://goodereader.com/apps/wp-content/uploads/downloads/thumbnails/2012/01/hi-256-0-99dda8c730196ab93c67f0659d5b8489abdeb977.png",
			"http://1.bp.blogspot.com/-mlaJ4p_3rBU/TdD9OWxN8II/AAAAAAAAE8U/xyynWwr3_4Q/s1600/antivitus_free.png",
			"http://cdn3.iconfinder.com/data/icons/transformers/computer.png",
			"http://cdn.geekwire.com/wp-content/uploads/2011/04/firefox.png?7794fe",
			"https://ssl.gstatic.com/android/market/com.rovio.angrybirdsseasons/hi-256-9-347dae230614238a639d21508ae492302340b2ba",
			"http://androidblaze.com/wp-content/uploads/2011/12/tablet-pc-256x256.jpg",
			"http://www.theblaze.com/wp-content/uploads/2011/08/Apple.png",
			"http://1.bp.blogspot.com/-y-HQwQ4Kuu0/TdD9_iKIY7I/AAAAAAAAE88/3G4xiclDZD0/s1600/Twitter_Android.png",
			"http://3.bp.blogspot.com/-nAf4IMJGpc8/TdD9OGNUHHI/AAAAAAAAE8E/VM9yU_lIgZ4/s1600/Adobe%2BReader_Android.png",
			"http://cdn.geekwire.com/wp-content/uploads/2011/05/oovoo-android.png?7794fe",
			"http://icons.iconarchive.com/icons/kocco/ndroid/128/android-market-2-icon.png",
			"http://thecustomizewindows.com/wp-content/uploads/2011/11/Nicest-Android-Live-Wallpapers.png",
			"http://c.wrzuta.pl/wm16596/a32f1a47002ab3a949afeb4f",
			"http://macprovid.vo.llnwd.net/o43/hub/media/1090/6882/01_headline_Muse.jpg",
			// Special cases
			"http://cdn.urbanislandz.com/wp-content/uploads/2011/10/MMSposter-large.jpg", // very large image
			"file:///sdcard/Universal Image Loader @#&=+-_.,!()~'%20.png", // Image from SD card with encoded symbols
			"assets://Living Things @#&=+-_.,!()~'%20.jpg", // Image from assets
			"drawable://" + R.drawable.ic_launcher, // Image from drawables
			"http://upload.wikimedia.org/wikipedia/ru/b/b6/袣邪泻_泻芯褌_褋_屑褘褕邪屑懈_胁芯械胁邪谢.png", // Link with UTF-8
			"https://www.eff.org/sites/default/files/chrome150_0.jpg", // Image from HTTPS
			"http://bit.ly/soBiXr", // Redirect link
			"http://img001.us.expono.com/100001/100001-1bc30-2d736f_m.jpg", // EXIF
			"", // Empty link
			"http://wrong.site.com/corruptedLink", // Wrong link
	};

	private Constants() {
	}

	// 配置
	public static class Config {
		public static final boolean DEVELOPER_MODE = false;
	}
	
	// 额外类
	public static class Extra {
		public static final String IMAGES = "com.nostra13.example.universalimageloader.IMAGES";
		public static final String IMAGE_POSITION = "com.nostra13.example.universalimageloader.IMAGE_POSITION";
	}
}

/2013.8.19_Universal_Image_Loader_Demo/src/com/nostra13/example/universalimageloader/ImageListActivity.java

/*******************************************************************************
 * Copyright 2011-2013 Sergey Tarasevich
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
package com.nostra13.example.universalimageloader;

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;

import com.nostra13.example.universalimageloader.Constants.Extra;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.assist.ImageLoadingListener;
import com.nostra13.universalimageloader.core.assist.SimpleImageLoadingListener;
import com.nostra13.universalimageloader.core.display.FadeInBitmapDisplayer;
import com.nostra13.universalimageloader.core.display.RoundedBitmapDisplayer;

/**
 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
 */
public class ImageListActivity extends AbsListViewBaseActivity {

	DisplayImageOptions options;		// DisplayImageOptions是用于设置图片显示的类

	String[] imageUrls;					// 图片路径

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.ac_image_list);

		Bundle bundle = getIntent().getExtras();
		imageUrls = bundle.getStringArray(Extra.IMAGES);

		// 使用DisplayImageOptions.Builder()创建DisplayImageOptions
		options = new DisplayImageOptions.Builder()
			.showStubImage(R.drawable.ic_stub)			// 设置图片下载期间显示的图片
			.showImageForEmptyUri(R.drawable.ic_empty)	// 设置图片Uri为空或是错误的时候显示的图片
			.showImageOnFail(R.drawable.ic_error)		// 设置图片加载或解码过程中发生错误显示的图片	
			.cacheInMemory(true)						// 设置下载的图片是否缓存在内存中
			.cacheOnDisc(true)							// 设置下载的图片是否缓存在SD卡中
			.displayer(new RoundedBitmapDisplayer(20))	// 设置成圆角图片
			.build();									// 创建配置过得DisplayImageOption对象

		listView = (ListView) findViewById(android.R.id.list);
		((ListView) listView).setAdapter(new ItemAdapter());
		listView.setOnItemClickListener(new OnItemClickListener() {
			@Override
			public void onItemClick(AdapterView parent, View view, int position, long id) {
				// 点击列表项转入ViewPager显示界面
				startImagePagerActivity(position);		
			}
		});
	}

	@Override
	public void onBackPressed() {
		AnimateFirstDisplayListener.displayedImages.clear();
		super.onBackPressed();
	}

	private void startImagePagerActivity(int position) {
		Intent intent = new Intent(this, ImagePagerActivity.class);
		intent.putExtra(Extra.IMAGES, imageUrls);
		intent.putExtra(Extra.IMAGE_POSITION, position);
		startActivity(intent);
	}

	
	/**
	 * 
	 * 自定义列表项适配器
	 *
	 */
	class ItemAdapter extends BaseAdapter {

		private ImageLoadingListener animateFirstListener = new AnimateFirstDisplayListener();

		private class ViewHolder {
			public TextView text;
			public ImageView image;
		}

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

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

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

		@Override
		public View getView(final int position, View convertView, ViewGroup parent) {
			View view = convertView;
			final ViewHolder holder;
			if (convertView == null) {
				view = getLayoutInflater().inflate(R.layout.item_list_image, parent, false);
				holder = new ViewHolder();
				holder.text = (TextView) view.findViewById(R.id.text);
				holder.image = (ImageView) view.findViewById(R.id.image);
				view.setTag(holder);		// 给View添加一个格外的数据
			} else {
				holder = (ViewHolder) view.getTag(); // 把数据取出来
			}

			holder.text.setText("Item " + (position + 1));	// TextView设置文本

			/**
			 * 显示图片
			 * 参数1：图片url
			 * 参数2：显示图片的控件
			 * 参数3：显示图片的设置
			 * 参数4：监听器
			 */
			imageLoader.displayImage(imageUrls[position], holder.image, options, animateFirstListener);

			return view;
		}
	}

	/**
	 * 图片加载第一次显示监听器
	 * @author Administrator
	 *
	 */
	private static class AnimateFirstDisplayListener extends SimpleImageLoadingListener {
		
		static final List displayedImages = Collections.synchronizedList(new LinkedList());

		@Override
		public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
			if (loadedImage != null) {
				ImageView imageView = (ImageView) view;
				// 是否第一次显示
				boolean firstDisplay = !displayedImages.contains(imageUri);
				if (firstDisplay) {
					// 图片淡入效果
					FadeInBitmapDisplayer.animate(imageView, 500);
					displayedImages.add(imageUri);
				}
			}
		}
	}
}

/2013.8.19_Universal_Image_Loader_Demo/src/com/nostra13/example/universalimageloader/ImageGridActivity.java

网格视图Activity

/*******************************************************************************
 * Copyright 2011-2013 Sergey Tarasevich
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
package com.nostra13.example.universalimageloader;

import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.BaseAdapter;
import android.widget.GridView;
import android.widget.ImageView;

import com.nostra13.example.universalimageloader.Constants.Extra;
import com.nostra13.universalimageloader.core.DisplayImageOptions;

/**
 * 网格视图显示Activity
 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
 */
public class ImageGridActivity extends AbsListViewBaseActivity {

	String[] imageUrls;					// 图片Url

	DisplayImageOptions options;		// 显示图片的设置

	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.ac_image_grid);

		Bundle bundle = getIntent().getExtras();
		imageUrls = bundle.getStringArray(Extra.IMAGES);

		options = new DisplayImageOptions.Builder()
			.showStubImage(R.drawable.ic_stub)
			.showImageForEmptyUri(R.drawable.ic_empty)
			.showImageOnFail(R.drawable.ic_error)
			.cacheInMemory(true)
			.cacheOnDisc(true)
			.bitmapConfig(Bitmap.Config.RGB_565)	 //设置图片的解码类型
			.build();

		listView = (GridView) findViewById(R.id.gridview);
		((GridView) listView).setAdapter(new ImageAdapter());			// 填充数据
		listView.setOnItemClickListener(new OnItemClickListener() {
			@Override
			public void onItemClick(AdapterView parent, View view, int position, long id) {
				startImagePagerActivity(position);
			}
		});
	}

	private void startImagePagerActivity(int position) {
		Intent intent = new Intent(this, ImagePagerActivity.class);
		intent.putExtra(Extra.IMAGES, imageUrls);
		intent.putExtra(Extra.IMAGE_POSITION, position);
		startActivity(intent);
	}

	public class ImageAdapter extends BaseAdapter {
		@Override
		public int getCount() {
			return imageUrls.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) {
			final ImageView imageView;
			if (convertView == null) {
				imageView = (ImageView) getLayoutInflater().inflate(R.layout.item_grid_image, parent, false);
			} else {
				imageView = (ImageView) convertView;
			}

			// 将图片显示任务增加到执行池，图片将被显示到ImageView当轮到此ImageView
			imageLoader.displayImage(imageUrls[position], imageView, options);

			return imageView;
		}
	}
}

/2013.8.19_Universal_Image_Loader_Demo/src/com/nostra13/example/universalimageloader/ImagePagerActivity.java

ViewPager视图Activity

/*******************************************************************************
 * Copyright 2011-2013 Sergey Tarasevich
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
package com.nostra13.example.universalimageloader;

import android.graphics.Bitmap;
import android.os.Bundle;
import android.os.Parcelable;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.ProgressBar;
import android.widget.Toast;

import com.nostra13.example.universalimageloader.Constants.Extra;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.assist.FailReason;
import com.nostra13.universalimageloader.core.assist.ImageScaleType;
import com.nostra13.universalimageloader.core.assist.SimpleImageLoadingListener;
import com.nostra13.universalimageloader.core.display.FadeInBitmapDisplayer;

/**
 * ViewPager页面显示Activity
 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
 */
public class ImagePagerActivity extends BaseActivity {

	private static final String STATE_POSITION = "STATE_POSITION";

	DisplayImageOptions options;

	ViewPager pager;

	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.ac_image_pager);

		Bundle bundle = getIntent().getExtras();
		String[] imageUrls = bundle.getStringArray(Extra.IMAGES);
		// 当前显示View的位置
		int pagerPosition = bundle.getInt(Extra.IMAGE_POSITION, 0);

		// 如果之前有保存用户数据
		if (savedInstanceState != null) {
			pagerPosition = savedInstanceState.getInt(STATE_POSITION);
		}

		options = new DisplayImageOptions.Builder()
			.showImageForEmptyUri(R.drawable.ic_empty)
			.showImageOnFail(R.drawable.ic_error)
			.resetViewBeforeLoading(true)
			.cacheOnDisc(true)
			.imageScaleType(ImageScaleType.EXACTLY)
			.bitmapConfig(Bitmap.Config.RGB_565)
			.displayer(new FadeInBitmapDisplayer(300))
			.build();

		pager = (ViewPager) findViewById(R.id.pager);
		pager.setAdapter(new ImagePagerAdapter(imageUrls));
		pager.setCurrentItem(pagerPosition);	// 显示当前位置的View
	}

	@Override
	public void onSaveInstanceState(Bundle outState) {
		// 保存用户数据
		outState.putInt(STATE_POSITION, pager.getCurrentItem());
	}

	private class ImagePagerAdapter extends PagerAdapter {

		private String[] images;
		private LayoutInflater inflater;

		ImagePagerAdapter(String[] images) {
			this.images = images;
			inflater = getLayoutInflater();
		}

		@Override
		public void destroyItem(ViewGroup container, int position, Object object) {
			((ViewPager) container).removeView((View) object);
		}

		@Override
		public void finishUpdate(View container) {
		}

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

		@Override
		public Object instantiateItem(ViewGroup view, int position) {
			View imageLayout = inflater.inflate(R.layout.item_pager_image, view, false);
			ImageView imageView = (ImageView) imageLayout.findViewById(R.id.image);
			final ProgressBar spinner = (ProgressBar) imageLayout.findViewById(R.id.loading);

			imageLoader.displayImage(images[position], imageView, options, new SimpleImageLoadingListener() {
				@Override
				public void onLoadingStarted(String imageUri, View view) {
					spinner.setVisibility(View.VISIBLE);
				}

				@Override
				public void onLoadingFailed(String imageUri, View view, FailReason failReason) {
					String message = null;
					switch (failReason.getType()) {		// 获取图片失败类型
						case IO_ERROR:				// 文件I/O错误
							message = "Input/Output error";
							break;
						case DECODING_ERROR:		// 解码错误
							message = "Image can't be decoded";
							break;
						case NETWORK_DENIED:		// 网络延迟
							message = "Downloads are denied";
							break;
						case OUT_OF_MEMORY:		    // 内存不足
							message = "Out Of Memory error";
							break;
						case UNKNOWN:				// 原因不明
							message = "Unknown error";
							break;
					}
					Toast.makeText(ImagePagerActivity.this, message, Toast.LENGTH_SHORT).show();

					spinner.setVisibility(View.GONE);
				}

				@Override
				public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
					spinner.setVisibility(View.GONE);		// 不显示圆形进度条
				}
			});

			((ViewPager) view).addView(imageLayout, 0);		// 将图片增加到ViewPager
			return imageLayout;
		}

		@Override
		public boolean isViewFromObject(View view, Object object) {
			return view.equals(object);
		}

		@Override
		public void restoreState(Parcelable state, ClassLoader loader) {
		}

		@Override
		public Parcelable saveState() {
			return null;
		}

		@Override
		public void startUpdate(View container) {
		}
	}
}

/2013.8.19_Universal_Image_Loader_Demo/src/com/nostra13/example/universalimageloader/ImageGalleryActivity.java

画廊视图的Activity

/*******************************************************************************
 * Copyright 2011-2013 Sergey Tarasevich
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
package com.nostra13.example.universalimageloader;

import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
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 com.nostra13.example.universalimageloader.Constants.Extra;
import com.nostra13.universalimageloader.core.DisplayImageOptions;

/**
 * 画廊视图Activity
 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
 */
@SuppressWarnings("deprecation")
public class ImageGalleryActivity extends BaseActivity {

	String[] imageUrls;

	DisplayImageOptions options;

	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.ac_image_gallery);

		Bundle bundle = getIntent().getExtras();
		imageUrls = bundle.getStringArray(Extra.IMAGES);

		options = new DisplayImageOptions.Builder()
			.showStubImage(R.drawable.ic_stub)
			.showImageForEmptyUri(R.drawable.ic_empty)
			.showImageOnFail(R.drawable.ic_error)
			.cacheInMemory(true)
			.cacheOnDisc(true)
			.bitmapConfig(Bitmap.Config.RGB_565)
			.build();

		// 自API 16之后就被抛弃了
		Gallery gallery = (Gallery) findViewById(R.id.gallery);
		gallery.setAdapter(new ImageGalleryAdapter());
		gallery.setOnItemClickListener(new OnItemClickListener() {
			@Override
			public void onItemClick(AdapterView parent, View view, int position, long id) {
				startImagePagerActivity(position);
			}
		});
	}

	private void startImagePagerActivity(int position) {
		Intent intent = new Intent(this, ImagePagerActivity.class);
		intent.putExtra(Extra.IMAGES, imageUrls);
		intent.putExtra(Extra.IMAGE_POSITION, position);
		startActivity(intent);
	}

	private class ImageGalleryAdapter extends BaseAdapter {
		@Override
		public int getCount() {
			return imageUrls.length;
		}

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

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

		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			ImageView imageView = (ImageView) convertView;
			if (imageView == null) {
				imageView = (ImageView) getLayoutInflater().inflate(R.layout.item_gallery_image, parent, false);
			}
			imageLoader.displayImage(imageUrls[position], imageView, options);
			return imageView;
		}
	}
}

关于桌面控件的代码我就不贴了，朋友们可以自己下载我这个Demo

还有就是Manifest文件代码

以上的代码已经很详尽了，读者可以把它整合到你的项目当中，就可以实现完美异步加载图片。在这里要感谢那些为我们开源的大神们，他们的贡献让我们这些开发者更快更有效的完成工作，希望我们的开源会越做越好，我相信我们的开发者有这个能力。