android - doInBackground 方法中的异常

Question

try {
    Get_Webpage obj = new Get_Webpage(url);
    directory_listings = obj.get_webpage_source();
} catch (Exception e) {
    finish();
    m_ProgressDialog.dismiss();
    Toast.makeText(this, "You have to be connected to the internet for this application to work", Toast.LENGTH_LONG).show();
}


02-28 22:23:21.055: E/AndroidRuntime(2170): FATAL EXCEPTION: AsyncTask #1
02-28 22:23:21.055: E/AndroidRuntime(2170): java.lang.RuntimeException: An error occured while executing doInBackground()
02-28 22:23:21.055: E/AndroidRuntime(2170):     at android.os.AsyncTask$3.done(AsyncTask.java:200)
02-28 22:23:21.055: E/AndroidRuntime(2170):     at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274)
02-28 22:23:21.055: E/AndroidRuntime(2170):     at java.util.concurrent.FutureTask.setException(FutureTask.java:125)
02-28 22:23:21.055: E/AndroidRuntime(2170):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308)
02-28 22:23:21.055: E/AndroidRuntime(2170):     at java.util.concurrent.FutureTask.run(FutureTask.java:138)
02-28 22:23:21.055: E/AndroidRuntime(2170):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
02-28 22:23:21.055: E/AndroidRuntime(2170):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
02-28 22:23:21.055: E/AndroidRuntime(2170):     at java.lang.Thread.run(Thread.java:1019)
02-28 22:23:21.055: E/AndroidRuntime(2170): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
02-28 22:23:21.055: E/AndroidRuntime(2170):     at android.os.Handler.<init>(Handler.java:121)
02-28 22:23:21.055: E/AndroidRuntime(2170):     at android.widget.Toast.<init>(Toast.java:68)
02-28 22:23:21.055: E/AndroidRuntime(2170):     at android.widget.Toast.makeText(Toast.java:231)
02-28 22:23:21.055: E/AndroidRuntime(2170):     at net.website.qt.mediaplayer.Main.showToast(Main.java:414)
02-28 22:23:21.055: E/AndroidRuntime(2170):     at net.website.qt.mediaplayer.Main.access$15(Main.java:413)
02-28 22:23:21.055: E/AndroidRuntime(2170):     at net.website.qt.mediaplayer.Main$taskDoSomething.doInBackground(Main.java:199)
02-28 22:23:21.055: E/AndroidRuntime(2170):     at net.website.qt.mediaplayer.Main$taskDoSomething.doInBackground(Main.java:1)
02-28 22:23:21.055: E/AndroidRuntime(2170):     at android.os.AsyncTask$2.call(AsyncTask.java:185)
02-28 22:23:21.055: E/AndroidRuntime(2170):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306)
02-28 22:23:21.055: E/AndroidRuntime(2170):     ... 4 more

更新

@Override 
protected void onPostExecute(List<Employee> result) 
{            
    m_Employee.clear();     
    m_Employee.addAll(result);   
    m_ProgressDialog.dismiss();
    m_adapter.notifyDataSetChanged();   
} 

我在应用程序中有这么长的处理任务

据我了解，SwingWorker中的doInBackground方法不是应该对用户界面做任何事情。然而，我在那里所做的可能抛出异常，我想通过向用户发送错误消息来处理。

我该如何处理？

private class taskDoSomething extends AsyncTask<Void, Void, List<Employee>> 
{ 

    @Override 
    protected List<Employee> doInBackground(Void... params) 
    { 
    String url = "http://ofertaweb.ro/android/sleepandlovemusic/list_files.php";

    try {
        Get_Webpage obj = new Get_Webpage(url);
        directory_listings = obj.get_webpage_source();
    } catch (Exception e) {
         Toast.makeText(this, "You have to be connected to the internet for this application to work", Toast.LENGTH_LONG).show();
       finish();
    }

使用 logcat 更新:

02-28 21:47:01.194: W/dalvikvm(1820): threadid=9: thread exiting with uncaught exception (group=0x40015560)
02-28 21:47:01.314: E/AndroidRuntime(1820): FATAL EXCEPTION: AsyncTask #1
02-28 21:47:01.314: E/AndroidRuntime(1820): java.lang.RuntimeException: An error occured while executing doInBackground()
02-28 21:47:01.314: E/AndroidRuntime(1820):     at android.os.AsyncTask$3.done(AsyncTask.java:200)
02-28 21:47:01.314: E/AndroidRuntime(1820):     at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274)
02-28 21:47:01.314: E/AndroidRuntime(1820):     at java.util.concurrent.FutureTask.setException(FutureTask.java:125)
02-28 21:47:01.314: E/AndroidRuntime(1820):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308)
02-28 21:47:01.314: E/AndroidRuntime(1820):     at java.util.concurrent.FutureTask.run(FutureTask.java:138)
02-28 21:47:01.314: E/AndroidRuntime(1820):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088)
02-28 21:47:01.314: E/AndroidRuntime(1820):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581)
02-28 21:47:01.314: E/AndroidRuntime(1820):     at java.lang.Thread.run(Thread.java:1019)
02-28 21:47:01.314: E/AndroidRuntime(1820): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
02-28 21:47:01.314: E/AndroidRuntime(1820):     at android.os.Handler.<init>(Handler.java:121)
02-28 21:47:01.314: E/AndroidRuntime(1820):     at android.widget.Toast.<init>(Toast.java:68)
02-28 21:47:01.314: E/AndroidRuntime(1820):     at android.widget.Toast.makeText(Toast.java:231)
02-28 21:47:01.314: E/AndroidRuntime(1820):     at net.website.qt.mediaplayer.Main.showToast(Main.java:411)
02-28 21:47:01.314: E/AndroidRuntime(1820):     at net.website.qt.mediaplayer.Main.access$14(Main.java:410)
02-28 21:47:01.314: E/AndroidRuntime(1820):     at net.website.qt.mediaplayer.Main$taskDoSomething.doInBackground(Main.java:197)
02-28 21:47:01.314: E/AndroidRuntime(1820):     at net.website.qt.mediaplayer.Main$taskDoSomething.doInBackground(Main.java:1)
02-28 21:47:01.314: E/AndroidRuntime(1820):     at android.os.AsyncTask$2.call(AsyncTask.java:185)
02-28 21:47:01.314: E/AndroidRuntime(1820):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306)
02-28 21:47:01.314: E/AndroidRuntime(1820):     ... 4 more
02-28 21:47:02.954: E/WindowManager(1820): Activity net.website.qt.mediaplayer.Main has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@40525ae0 that was originally added here
02-28 21:47:02.954: E/WindowManager(1820): android.view.WindowLeaked: Activity net.website.qt.mediaplayer.Main has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@40525ae0 that was originally added here
02-28 21:47:02.954: E/WindowManager(1820):  at android.view.ViewRoot.<init>(ViewRoot.java:258)
02-28 21:47:02.954: E/WindowManager(1820):  at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:148)
02-28 21:47:02.954: E/WindowManager(1820):  at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)
02-28 21:47:02.954: E/WindowManager(1820):  at android.view.Window$LocalWindowManager.addView(Window.java:424)
02-28 21:47:02.954: E/WindowManager(1820):  at android.app.Dialog.show(Dialog.java:241)
02-28 21:47:02.954: E/WindowManager(1820):  at android.app.ProgressDialog.show(ProgressDialog.java:107)
02-28 21:47:02.954: E/WindowManager(1820):  at android.app.ProgressDialog.show(ProgressDialog.java:90)
02-28 21:47:02.954: E/WindowManager(1820):  at net.website.qt.mediaplayer.Main.onCreate(Main.java:136)
02-28 21:47:02.954: E/WindowManager(1820):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-28 21:47:02.954: E/WindowManager(1820):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
02-28 21:47:02.954: E/WindowManager(1820):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
02-28 21:47:02.954: E/WindowManager(1820):  at android.app.ActivityThread.access$1500(ActivityThread.java:117)
02-28 21:47:02.954: E/WindowManager(1820):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
02-28 21:47:02.954: E/WindowManager(1820):  at android.os.Handler.dispatchMessage(Handler.java:99)
02-28 21:47:02.954: E/WindowManager(1820):  at android.os.Looper.loop(Looper.java:123)
02-28 21:47:02.954: E/WindowManager(1820):  at android.app.ActivityThread.main(ActivityThread.java:3683)
02-28 21:47:02.954: E/WindowManager(1820):  at java.lang.reflect.Method.invokeNative(Native Method)
02-28 21:47:02.954: E/WindowManager(1820):  at java.lang.reflect.Method.invoke(Method.java:507)
02-28 21:47:02.954: E/WindowManager(1820):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
02-28 21:47:02.954: E/WindowManager(1820):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
02-28 21:47:02.954: E/WindowManager(1820):  at dalvik.system.NativeStart.main(Native Method)

更新结束

Answer 1

这里的重要信息是: Activity net.website.qt.mediaplayer.Main 泄露了最初添加到此处的窗口 com.android.internal.policy.impl.PhoneWindow$DecorView@40525ae0

这是一个非常常见的错误，已经在 SO 上多次解决:

Activity has leaked window that was originally added

Activity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@46368a28 that was originally added here

我很确定违规行是:

     Toast.makeText(this, "You have to be connected to the internet for this application to work", Toast.LENGTH_LONG).show();

Toast.makeText 将 Context 作为其第一个参数，而不是 AsyncTask。在这种情况下，当您使用 this 时，它指向 AsyncTask 而不是导致问题的 Context。