blocks|key|748648|text|我不认为AsyncTask中内置了这样的东西。你的方法看起来很好。只要确保定期检查AsyncTask的doInBackground方法中的isCancelled()的值，以便在UI线程取消该方法时结束该方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|748649|如果出于某些原因不想使用处理程序，可以在AsyncTask中定期检查System.currentTimeMillis并在超时时退出，尽管我更喜欢您的解决方案，因为它实际上会中断线程。|748650|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

I don't think there's anything like that built into AsyncTask. Your approach seems to be a good one. Just be sure to periodically check the value of isCancelled() in your AsyncTask's doInBackground method to end this method once the UI thread cancels it.

If you want to avoid using the handler for some reason, you could check System.currentTimeMillis periodically within your AsyncTask and exit on timeout, although I like your solution better since it can actually interrupt the thread.

blocks|key|748679|text|是的，有AsyncTask.get()|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|748680|myDownloader.get(30000,+TimeUnit.MILLISECONDS);|code-block|syntax|javascript|748681|请注意，通过在主线程中调用它(AKA。UI线程)将阻塞执行，您可能需要在单独的线程中调用它。|748682|entityMap|0|LINK|mutability|MUTABLE|url|http://developer.android.com/reference/android/os/AsyncTask.html#get%2528long,%2520java.util.concurrent.TimeUnit%2529^0|4|F|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@$A|T|B|U|1|V]]|C|$]]|$1|D|3|E|5|F|7|W|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|X|8|@]|9|@]|C|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]]]

Yes, there is <a href="http://developer.android.com/reference/android/os/AsyncTask.html#get%28long,%20java.util.concurrent.TimeUnit%29">AsyncTask.get()</a>

<pre><code>myDownloader.get(30000, TimeUnit.MILLISECONDS);
</code></pre>

Note that by calling this in main thread (AKA. UI thread) will block execution, You probably need call it in a separate thread.

blocks|key|532272|text|+++++++++Context+mContext;

+++++++++@Override
+++++++++protected+void+onCreate(Bundle+savedInstanceState)+{
++++++++++++super.onCreate(savedInstanceState);
++++++++++++++++++++++++++++++++++++mContext+=+this;

++++++++++++//async+task
++++++++++++final+RunTask+tsk+=+new+RunTask+();+
++++++++++++tsk.execute();

++++++++++++//setting+timeout+thread+for+async+task
++++++++++++Thread+thread1+=+new+Thread(){
++++++++++++public+void+run(){
++++++++++++++++try+{
++++++++++++++++++++tsk.get(30000,+TimeUnit.MILLISECONDS);++//set+time+in+milisecond(in+this+timeout+is+30+seconds

++++++++++++++++}+catch+(Exception+e)+{
++++++++++++++++++++tsk.cancel(true);+++++++++++++++++++++++++++
++++++++++++++++++++((Activity)+mContext).runOnUiThread(new+Runnable()
++++++++++++++++++++{
+++++++++++++++++++++++++@SuppressLint("ShowToast")
++++++++++++++++++++++++public+void+run()
+++++++++++++++++++++++++{
++++++++++++++++++++++++++++Toast.makeText(mContext,+"Time+Out.",+Toast.LENGTH_LONG).show();
++++++++++++++++++++++++++++finish();+//will+close+the+current+activity+comment+if+you+don't+want+to+close+current+activity.++++++++++++++++++++++++++++++++
+++++++++++++++++++++++++}
++++++++++++++++++++});
++++++++++++++++}
++++++++++++}
++++++++};
++++++++thread1.start();

+++++++++}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|532273|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code> Context mContext;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 mContext = this;

 //async task
 final RunTask tsk = new RunTask (); 
 tsk.execute();

 //setting timeout thread for async task
 Thread thread1 = new Thread(){
 public void run(){
 try {
 tsk.get(30000, TimeUnit.MILLISECONDS); //set time in milisecond(in this timeout is 30 seconds

 } catch (Exception e) {
 tsk.cancel(true); 
 ((Activity) mContext).runOnUiThread(new Runnable()
 {
 @SuppressLint("ShowToast")
 public void run()
 {
 Toast.makeText(mContext, "Time Out.", Toast.LENGTH_LONG).show();
 finish(); //will close the current activity comment if you don't want to close current activity. 
 }
 });
 }
 }
 };
 thread1.start();

 }
</code></pre>

blocks|key|748781|text|在这种情况下，您的下载器基于URL连接，您有许多参数可以帮助您定义超时，而不需要复杂的代码：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|748782|++HttpURLConnection+urlc+=+(HttpURLConnection)+url.openConnection();

++urlc.setConnectTimeout(15000);

++urlc.setReadTimeout(15000);|code-block|syntax|javascript|748783|如果你只是把这段代码带到你的异步任务中，这是可以的。|748784|“读取超时”是在整个传输过程中测试一个坏的网络。|748785|“'Connection”仅在开始时调用，用于测试服务器是否启动。|748786|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

In the case, your downloader is based upon an for an URL connection, you have a number of parameters that could help you to define a timeout without complex code:

<pre><code> HttpURLConnection urlc = (HttpURLConnection) url.openConnection();

 urlc.setConnectTimeout(15000);

 urlc.setReadTimeout(15000);
</code></pre>

If you just bring this code into your async task, it is ok.

'Read Timeout' is to test a bad network all along the transfer.

'Connection Timeout' is only called at the beginning to test if the server is up or not.

blocks|key|748840|text|您可以再添加一个条件，以使取消更健壮。例如，|type|unstyled|depth|inlineStyleRanges|entityRanges|data|748841|+if+(downloader.getStatus()+==+AsyncTask.Status.RUNNING+%7C%7C+downloader.getStatus()+==+AsyncTask.Status.PENDING)
+++++downloader.cancel(true);|code-block|syntax|javascript|748842|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You can put one more condition to make cancellation more robust. e.g.,

<pre><code> if (downloader.getStatus() == AsyncTask.Status.RUNNING || downloader.getStatus() == AsyncTask.Status.PENDING)
 downloader.cancel(true);
</code></pre>

blocks|key|532468|text|在onPreExecute()方法中AsyncTask的扩展类旁边使用CountDownTimer类：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|532469|主要优点是，异步监控在类内部完成。|532470|public+class+YouExtendedClass+extends+AsyncTask<String,Integer,String>+{
...
public+YouExtendedClass+asyncObject;+++//+as+CountDownTimer+has+similar+method+->+to+prevent+shadowing
...
@Override
protected+void+onPreExecute()+{
++++asyncObject+=+this;
++++new+CountDownTimer(7000,+7000)+{
++++++++public+void+onTick(long+millisUntilFinished)+{
++++++++++++//+You+can+monitor+the+progress+here+as+well+by+changing+the+onTick()+time
++++++++}
++++++++public+void+onFinish()+{
++++++++++++//+stop+async+task+if+not+in+progress
++++++++++++if+(asyncObject.getStatus()+==+AsyncTask.Status.RUNNING)+{
++++++++++++++++asyncObject.cancel(false);
++++++++++++++++//+Add+any+specific+task+you+wish+to+do+as+your+extended+class+variable+works+here+as+well.
++++++++++++}
++++++++}
++++}.start();
...|code-block|syntax|javascript|532471|例如，更改CountDownTimer(7000,7000)+->+CountDownTimer(7000,1000)，它将在调用onFinish()之前调用onTick()+6次。如果您想要添加一些监控，这是很好的。|532472|感谢我在这个页面上得到的所有好的建议:-)|532473|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|S|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Use CountDownTimer Class in side the extended class for AsyncTask in the onPreExecute() method: 

Main advantage, the Async monitoring done internally in the class.

<pre><code>public class YouExtendedClass extends AsyncTask&lt;String,Integer,String&gt; {
...
public YouExtendedClass asyncObject; // as CountDownTimer has similar method -&gt; to prevent shadowing
...
@Override
protected void onPreExecute() {
 asyncObject = this;
 new CountDownTimer(7000, 7000) {
 public void onTick(long millisUntilFinished) {
 // You can monitor the progress here as well by changing the onTick() time
 }
 public void onFinish() {
 // stop async task if not in progress
 if (asyncObject.getStatus() == AsyncTask.Status.RUNNING) {
 asyncObject.cancel(false);
 // Add any specific task you wish to do as your extended class variable works here as well.
 }
 }
 }.start();
...
</code></pre>

change CountDownTimer(7000, 7000) -> CountDownTimer(7000, 1000) for example and it will call onTick() 6 times before calling onFinish(). This is good if you want to add some monitoring.

Thanks for all the good advice I got in this page :-)

blocks|key|532527|text|从问题中得到启发，我写了一个方法，它通过AsyncTask完成一些后台任务，如果处理时间比LOADING_TIMEOUT多，那么会出现一个重试的警告对话框。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|532528|public+void+loadData()
++++{
++++++++final+Load+loadUserList=new+Load();
++++++++loadUserList.execute();
++++++++Handler+handler+=+new+Handler();
++++++++handler.postDelayed(new+Runnable()+{
++++++++++++@Override
++++++++++++public+void+run()+{
++++++++++++++++if+(loadUserList.getStatus()+==+AsyncTask.Status.RUNNING)+{
++++++++++++++++++++loadUserList.cancel(true);
++++++++++++++++++++pDialog.cancel();
++++++++++++++++++++new+AlertDialog.Builder(UserList.this)
++++++++++++++++++++++++++++.setTitle("Error..!")
++++++++++++++++++++++++++++.setMessage("Sorry+you+dont+have+proper+net+connectivity..!\nCheck+your+internet+settings+or+retry.")
++++++++++++++++++++++++++++.setCancelable(false)
++++++++++++++++++++++++++++.setPositiveButton("Retry",+new+DialogInterface.OnClickListener()+{
++++++++++++++++++++++++++++++++@Override
++++++++++++++++++++++++++++++++public+void+onClick(DialogInterface+dialogInterface,+int+i)+{
++++++++++++++++++++++++++++++++++++loadData();
++++++++++++++++++++++++++++++++}
++++++++++++++++++++++++++++})
++++++++++++++++++++++++++++.setNegativeButton("Exit",+new+DialogInterface.OnClickListener()+{
++++++++++++++++++++++++++++++++@Override


++++++++++++++++++++++public+void+onClick(DialogInterface+dialogInterface,+int+i)+{
++++++++++++++++++++++++++++++++System.exit(0);
++++++++++++++++++++++++++++}
++++++++++++++++++++++++})
++++++++++++++++++++++++.show();
++++++++++++}
++++++++}
++++},+LOADING_TIMEOUT);
++++return;
}|code-block|syntax|javascript|532529|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Inspiring from question I have written a method which do some background task via AsyncTask and if processing takes more then LOADING_TIMEOUT then an alert dialogue to retry will appear.

<pre><code>public void loadData()
 {
 final Load loadUserList=new Load();
 loadUserList.execute();
 Handler handler = new Handler();
 handler.postDelayed(new Runnable() {
 @Override
 public void run() {
 if (loadUserList.getStatus() == AsyncTask.Status.RUNNING) {
 loadUserList.cancel(true);
 pDialog.cancel();
 new AlertDialog.Builder(UserList.this)
 .setTitle("Error..!")
 .setMessage("Sorry you dont have proper net connectivity..!\nCheck your internet settings or retry.")
 .setCancelable(false)
 .setPositiveButton("Retry", new DialogInterface.OnClickListener() {
 @Override
 public void onClick(DialogInterface dialogInterface, int i) {
 loadData();
 }
 })
 .setNegativeButton("Exit", new DialogInterface.OnClickListener() {
 @Override


 public void onClick(DialogInterface dialogInterface, int i) {
 System.exit(0);
 }
 })
 .show();
 }
 }
 }, LOADING_TIMEOUT);
 return;
}
</code></pre>

I have an <code>AsyncTask</code> class that I execute that downloads a big list of data from a website.

In the case that the end user has a very slow or spotty data connection at the time of use, I'd like to make the <code>AsyncTask</code> timeout after a period of time. My first approach to this is like so:

<pre><code>MyDownloader downloader = new MyDownloader();
downloader.execute();
Handler handler = new Handler();
handler.postDelayed(new Runnable()
{
 @Override
 public void run() {
 if ( downloader.getStatus() == AsyncTask.Status.RUNNING )
 downloader.cancel(true);
 }
}, 30000 );
</code></pre>

After starting the <code>AsyncTask</code>, a new handler is started that will cancel the <code>AsyncTask</code> after 30 seconds if it's still running.

Is this a good approach? Or is there something built into <code>AsyncTask</code> that is better suited for this purpose?

Android - Setting a Timeout for an AsyncTask?

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我有一个我执行的AsyncTask类，它可以从网站上下载大量的数据。如果最终用户在使用时数据连接非常慢或不稳定，我希望在一段时间后使AsyncTask超时。我的第一种方法是这样的：MyDownloader downloader = new MyDownloader();downloader.execute();Hand...

问安卓-为AsyncTask设置超时？
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