LoadImage一个从网络访问图片，并存到缓存（内存，磁盘）直接可以用

<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">package</span> com.tarena.util;

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.ByteArrayOutputStream;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.File;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.FilenameFilter;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.IOException;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.InputStream;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.io.OutputStream;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.net.HttpURLConnection;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.net.ProtocolException;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.net.URL;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.security.MessageDigest;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.security.NoSuchAlgorithmException;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.util.concurrent.ExecutorService;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.util.concurrent.Executors;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> java.util.concurrent.LinkedBlockingDeque;

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.tarena.util.DiskLruCache.Editor;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> com.tarena.util.DiskLruCache.Snapshot;

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.R.integer;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.R.string;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.content.Context;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.content.pm.PackageInfo;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.content.pm.PackageManager.NameNotFoundException;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.graphics.Bitmap;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.graphics.Bitmap.CompressFormat;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.graphics.BitmapFactory;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.graphics.BitmapFactory.Options;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.os.Handler;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.os.Looper;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.os.Message;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.support.v4.util.LruCache;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.util.Log;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">import</span> android.widget.ImageView;

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ImageLoader</span> {</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//下载完成任务执行完毕后发消息</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> LOAD_FINISH =<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">102</span>;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> NEW_TASK =<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">102</span>;

<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//线程池中线程的数量、</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//（这个数量应该与设备cpu的核数相同）</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> Thread_Count;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//上下文</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> Context context;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//内存</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> LruCache<String, Bitmap> lruCache;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//双向队列，以后可以根据自己的需求选择对应的FIFO或者LIFO；</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> LinkedBlockingDeque<Runnable> blockingDeque;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//线程池</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> ExecutorService service;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//从任务队列中取下载人物的handler</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> Handler pollHandler;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//任务下载完毕后，用来刷新ListView条目显示下载图片内容</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> Handler uiHandler;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//养活PollHandler</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> Thread pollThread;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//标示的作用，用来确保ImageView只要进行一次赋值就可以。</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> isFirstTiem = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//存储到sdcard当中</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> DiskLruCache diskLruCache;

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-title" style="box-sizing: border-box;">ImageLoader</span>(){

}
<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
* 初始化所有属性的值
*<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @param</span> context  上下文
*/</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">inIt</span>(Context context){

<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//初始化上下文</span>
ImageLoader.context = context;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//初始化线程池中线程的数量</span>
Thread_Count = getNumberOfCores();
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//最大的缓存运行空间,内存缓存</span>
lruCache = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> LruCache<String, Bitmap>((<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span>) (Runtime.getRuntime().maxMemory()/<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">8</span>)){
<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">protected</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> <span class="hljs-title" style="box-sizing: border-box;">sizeOf</span>(String key, Bitmap value) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> value.getHeight()*value.getRowBytes();
}
};
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//初始化磁盘缓存</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//参数是：第一个是文件存储的路径，第二个是项目版本号，一个Key对应几个Value，存储空间是多少</span>
diskLruCache = DiskLruCache.open(directory(), appVersion(), <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1024</span>*<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1024</span>*<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">20</span>);
} <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (IOException e1) {
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// TODO Auto-generated catch block</span>
e1.printStackTrace();
}

<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//初始化消息队列</span>
blockingDeque = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> LinkedBlockingDeque<Runnable>();
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//初始化线程池</span>
service = Executors.newFixedThreadPool(Thread_Count);

uiHandler = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Handler(Looper.getMainLooper()){
<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">handleMessage</span>(Message msg) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (msg.what == LOAD_FINISH) {
ValueObject vObject = (ValueObject) msg.obj;

ImageView imageView = vObject.imageView;
String url = vObject.url;
Bitmap bitmap = vObject.bitmap;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (imageView.getTag().toString().equals(url)) {
imageView.setImageBitmap(bitmap);
}

}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span>{
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>.handleMessage(msg);
}
}
};

pollThread = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Thread(){
<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">run</span>() {
Looper.prepare();
pollHandler = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Handler(){
<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">handleMessage</span>(Message msg) {
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// TODO Auto-generated method stub</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (msg.what == NEW_TASK) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
Runnable runnable = blockingDeque.takeFirst();
service.execute(runnable);
} <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (InterruptedException e) {
e.printStackTrace();
}
}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span>{
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>.handleMessage(msg);
}
}
};
Looper.loop();
}
};
pollThread.start();
isFirstTiem = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>;
}
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> <span class="hljs-title" style="box-sizing: border-box;">appVersion</span>() {

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//获取系统的项目的版本号</span>
PackageInfo info = context.getPackageManager()
.getPackageInfo(context.getPackageName(), <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> info.versionCode;
} <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (NameNotFoundException e) {
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// TODO Auto-generated catch block</span>
e.printStackTrace();
}
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>;
}
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> File <span class="hljs-title" style="box-sizing: border-box;">directory</span>() {
String path = context.getExternalCacheDir().getPath();

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(path,<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"ImageLoaddercache"</span>);
}
<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
* 确定线程的数量
*<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @return</span>
*/</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> <span class="hljs-title" style="box-sizing: border-box;">getNumberOfCores</span>(){
File file = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"/sys/devices/system/cpu/"</span>);

File[] files = file.listFiles(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> FilenameFilter() {

<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">boolean</span> <span class="hljs-title" style="box-sizing: border-box;">accept</span>(File dir, String filename) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (filename.matches(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"cpu[0-9]"</span>)) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>;
}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span>{
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>;
}
}
});

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (files.length><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> files.length;
}<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span>{
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>;
}
}
<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
*
*<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @param</span> url
*<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @param</span> imageView
*/</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">loadImag</span>(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> String url,<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> ImageView imageView){
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (isFirstTiem) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">throw</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> RuntimeException(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"ImageLoad 未初始化"</span>);
}
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//判断，url所指定的图像是否在缓存中有保存</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//将url转换为MD5格式的字符串</span>
Bitmap bitmap = lruCache.get(getMD5(url));
imageView.setTag(getMD5(url));
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (bitmap != <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {
Log.i(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"TAG"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"图像是从内存缓存中加载的"</span>);
imageView.setImageBitmap(bitmap);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span>;
}

<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//判断磁盘缓存中url所指定的图像是否在缓存中有保存</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
Snapshot snap =diskLruCache.get(getMD5(url));

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (snap != <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>) {
InputStream inputStream = snap.getInputStream(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>);
bitmap = BitmapFactory.decodeStream(inputStream);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//将从磁盘缓存中获得的图片放到内存缓存当中，下次还是直接去内存缓存</span>
lruCache.put(getMD5(url), bitmap);

imageView.setImageBitmap(bitmap);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span>;
}
} <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (IOException e1) {
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// TODO Auto-generated catch block</span>
e1.printStackTrace();
}

<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//内存缓存，磁盘缓存，当中都没有找到图片，就需要去网络中去获取图片</span>
blockingDeque.add(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Runnable() {

<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">run</span>() {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
URL path = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> URL(url);
HttpURLConnection connection = (HttpURLConnection) path.openConnection();
connection.setRequestMethod(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"GET"</span>);
connection.setRequestProperty(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Content-Type"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"application/x-www-form-urlencoded"</span>);
connection.setDoInput(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>);
connection.connect();
InputStream inputStream = connection.getInputStream();
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//要适当的压缩处理</span>
Bitmap bitmap = compress(inputStream,imageView);
inputStream.close();
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//将从网络获取并处理过后的图片，存到内存缓存，</span>
lruCache.put(getMD5(url), bitmap);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//将从网络获取并处理过后的图片，存到磁盘缓存，</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//构建一个Editor对象，</span>
Editor editor = diskLruCache.edit(getMD5(url));
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//获取输出流对象</span>
OutputStream outputStream = editor.newOutputStream(<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//设置图片的压缩格式</span>
bitmap.compress(CompressFormat.JPEG, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">100</span>, outputStream);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//提交Editor进行存储</span>
editor.commit();
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//记录日志的方法</span>
diskLruCache.flush();

<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">/*
* 在给主线程发消息的时候，我要解决图片的重复加载问题，光传一个Bitmap是解决不了的
* 所以我要出一个ValueObject（imageview，图的Url，图）；
*/</span>
ValueObject object = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> ValueObject(imageView, getMD5(url), bitmap);
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//发消息到主线程，更新UI</span>
Message.obtain(uiHandler, LOAD_FINISH,object).sendToTarget();

} <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (Exception e) {
e.printStackTrace();
}

}

});
Message.obtain(pollHandler,NEW_TASK).sendToTarget();
}

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">ValueObject</span>{</span>
ImageView imageView ;
String url;
Bitmap bitmap;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-title" style="box-sizing: border-box;">ValueObject</span>(ImageView imageView, String url, Bitmap bitmap) {
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">super</span>();
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.imageView = imageView;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.url = url;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.bitmap = bitmap;
}

}

<span class="hljs-javadoc" style="color: rgb(136, 0, 0); box-sizing: border-box;">/**
* 根据要显示的ImageView的大小对图像进行压缩
*<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @param</span> inputStream
*<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @param</span> imageView
*<span class="hljs-javadoctag" style="color: rgb(102, 0, 102); box-sizing: border-box;"> @return</span>
*/</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> Bitmap <span class="hljs-title" style="box-sizing: border-box;">compress</span>(InputStream inputStream, ImageView imageView) {
Bitmap bitmap = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//1)现货的图像源的尺寸大小</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//借助Options来获得图像的大小</span>
ByteArrayOutputStream out = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> ByteArrayOutputStream();
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">byte</span> [] buff = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">byte</span>[<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">4096</span>];
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> len = -<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">while</span> ((len=inputStream.read(buff))!=-<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>) {
out.write(buff,<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>,len);
}

Options opts = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Options();
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//如果设置了这句话，decodeByteArray返回值为Null；</span>
opts.inJustDecodeBounds = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">true</span>;
BitmapFactory.decodeByteArray(out.toByteArray(), <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>, out.toByteArray().length,
opts);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> width = opts.outWidth;<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//图像的宽度(像素值)</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> height = opts.outHeight;<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//图像的高度(像素值)</span>

<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//在取ImageView的宽,高的时候。有的时候返回的是0</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> targetWidth = imageView.getWidth();
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> targetHeight = imageView.getHeight();
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//所以要进行判断，解决这种的情况，有两种解决办法，</span>
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//可以手动制定宽，高</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (targetHeight == <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span> || targetWidth == <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>) {
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//以当前设备的高度和宽度来作为压缩的依据</span>
targetWidth = context.getResources().getDisplayMetrics().widthPixels;
targetHeight = context.getResources().getDisplayMetrics().heightPixels;
}

<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//计算压缩比</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> sampleSize = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//判断我去图片的宽，高去除我装图片的容器得到的值，如果大于1.</span>
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (width*<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1.0</span> / targetWidth ><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span> || height*<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1.0</span>/targetHeight><span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>) {
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//就得到压缩比，他俩谁打取谁，记得要向上取整在转；</span>
sampleSize = (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span>) Math.ceil(Math.max((width*<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1.0</span> / targetWidth), (height*<span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1.0</span>/targetHeight)));
}
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//设置压缩比</span>
opts.inSampleSize = sampleSize;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//设置返回值不为空</span>
opts.inJustDecodeBounds = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">false</span>;
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//获得压缩后的图片</span>
bitmap = BitmapFactory.decodeByteArray(out.toByteArray(), <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0</span>, out.toByteArray().length, opts);
out.close();

} <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (Exception e) {
e.printStackTrace();
}
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> bitmap;
}

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">static</span> String <span class="hljs-title" style="box-sizing: border-box;">getMD5</span>(String url){
String result= <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">""</span>;
MessageDigest digest;
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
digest = MessageDigest.getInstance(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"MD5"</span>);
digest.update(url.getBytes());

<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">byte</span> [] bs = digest.digest();

StringBuilder sb = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> StringBuilder();
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> (<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">byte</span> b :bs) {
String str= Integer.toHexString(b & <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">0xff</span>);
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (str.length() == <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1</span>) {
sb.append(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"0"</span>);
}
sb.append(str);
}
result = sb.toString();
} <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (NoSuchAlgorithmException e) {
<span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">// TODO Auto-generated catch block</span>
e.printStackTrace();
}
<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> result;
}
}
</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"></ul>