标签：android 图片异步加载 universalimageloader
Android-Universal-Image-Loader是一个图片异步加载，缓存和显示的框架。这个框架已经被很多开发者所使用，是最常用的几个Android开源项目之一，主流的应用，随便反编译几个，都可以见到它的身影。淘宝，天猫，Facebook，京东商城等都用到了这个项目。
实例：UniversalImageLoaderDemo
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.rainsong.universalimageloaderdemo"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="19" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.INTERNET" />
<application
android:name="com.rainsong.universalimageloaderdemo.UILApplication"
android:allowBackup="true"
android:icon="@drawable/logo"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.rainsong.universalimageloaderdemo.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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:orientation="vertical"
tools:context=".MainActivity" >
<ListView
android:id="@+id/list"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</ListView>
</LinearLayout>
布局文件：item_list.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="wrap_content" > <ImageView android:id="@+id/image" android:layout_width="72dip" android:layout_height="72dip" android:layout_margin="3dip" android:adjustViewBounds="true" android:contentDescription="@string/descr_image" android:scaleType="centerCrop" /> <TextView android:id="@+id/text" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_gravity="start|center_vertical" android:layout_marginLeft="20dip" android:textSize="22sp" /> </LinearLayout>Java源代码文件：UILApplication.java
package com.rainsong.universalimageloaderdemo;
import java.io.File;
import com.nostra13.universalimageloader.cache.disc.impl.UnlimitedDiscCache;
import com.nostra13.universalimageloader.cache.disc.naming.Md5FileNameGenerator;
import com.nostra13.universalimageloader.cache.memory.impl.UsingFreqLimitedMemoryCache;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;
import com.nostra13.universalimageloader.core.assist.QueueProcessingType;
import com.nostra13.universalimageloader.core.download.BaseImageDownloader;
import com.nostra13.universalimageloader.utils.StorageUtils;
import android.app.Application;
import android.content.Context;
public class UILApplication extends Application {
@Override
public void onCreate() {
super.onCreate();
initImageLoader(getApplicationContext());
}
public static void initImageLoader(Context context) {
//缓存文件的目录
File cacheDir = StorageUtils.getOwnCacheDirectory(context, "universalimageloader/Cache");
ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(context)
.memoryCacheExtraOptions(480, 800) // max width, max height，即保存的每个缓存文件的最大长宽
.threadPoolSize(3) //线程池内线程的数量
.threadPriority(Thread.NORM_PRIORITY - 2)
.denyCacheImageMultipleSizesInMemory()
.diskCacheFileNameGenerator(new Md5FileNameGenerator()) //将保存的时候的URI名称用MD5 加密
.memoryCache(new UsingFreqLimitedMemoryCache(2 * 1024 * 1024))
.memoryCacheSize(2 * 1024 * 1024) // 内存缓存的最大值
.diskCacheSize(50 * 1024 * 1024) // SD卡缓存的最大值
.tasksProcessingOrder(QueueProcessingType.LIFO)
// 由原先的discCache -> diskCache
.diskCache(new UnlimitedDiscCache(cacheDir))//自定义缓存路径
.imageDownloader(new BaseImageDownloader(context, 5 * 1000, 30 * 1000)) // connectTimeout (5 s), readTimeout (30 s)超时时间
.writeDebugLogs() // Remove for release app
.build();
//全局初始化此配置
ImageLoader.getInstance().init(config);
}
}Java源代码文件：MainActivity.java
package com.rainsong.universalimageloaderdemo;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.display.RoundedBitmapDisplayer;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
public class MainActivity extends Activity {
private ImageLoader imageLoader;
private ListView lv;
private String[] imageUrls;
private DisplayImageOptions options;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
imageLoader = ImageLoader.getInstance();
lv = (ListView)findViewById(R.id.list);
imageUrls = Constants.images;
// 使用DisplayImageOptions.Builder()创建DisplayImageOptions
options = new DisplayImageOptions.Builder()
.showImageOnLoading(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
.cacheOnDisk(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(); // 构建完成
lv.setAdapter(new ItemListAdapter());
}
@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;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.item_clear_memory_cache:
ImageLoader.getInstance().clearMemoryCache();
return true;
case R.id.item_clear_disc_cache:
ImageLoader.getInstance().clearDiskCache();
return true;
default:
return false;
}
}
class ItemListAdapter extends BaseAdapter {
@Override
public int getCount() {
// TODO Auto-generated method stub
return imageUrls.length;
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return imageUrls[position];
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
ViewHolder holder = null;
if (convertView == null) {
convertView = getLayoutInflater().inflate(R.layout.item_list, parent, false);
holder = new ViewHolder();
holder.text = (TextView) convertView.findViewById(R.id.text);
holder.image = (ImageView) convertView.findViewById(R.id.image);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.text.setText("Item " + (position + 1));
imageLoader.displayImage(imageUrls[position], holder.image, options);
return convertView;
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
class ViewHolder {
public ImageView image;
public TextView text;
}
}
}
Android图片异步加载框架Android-Universal-Image-Loader
标签：android 图片异步加载 universalimageloader
原文地址：http://blog.csdn.net/hantangsongming/article/details/41961749
