doInBackground過程中的問題

調用該類時出現問題。我沒有得到解決我的確切問題。直到我的工作是：doInBackground過程中的問題

Task.java：

public class Task extends AsyncTask<Void, Void, String> 
{ 
    Context context; 
    FragmentActivity currentActivity; 
    ProgressDialog dialog; 
    public Task(FragmentActivity activity) 
    { 
     currentActivity = activity; 
     context=Constant.getContext(); 
    } 
    @Override 
    protected void onPreExecute() 
    { 
     dialog=ProgressDialog.show(currentActivity, "Please wait...", "Loading..."); 

} 

@Override 
protected String doInBackground(Void... params) 
{ 
    ActivityWeatherSetting hh = new ActivityWeatherSetting(); 
    hh.initialize(); 
    return "success"; 
} 

@Override 
protected void onPostExecute(String params) 
{ 
    //asyncclass.dismissProgressDialog(); 
    dialog.dismiss(); 
} 
}

AsyncClass.java：

public abstract class AsyncClass extends Activity 
{ 
    protected static final String TAG = AsyncClass.class.getSimpleName(); 


public ProgressDialog progressDialog; 

private boolean destroyed = false; 

Context context; 

@Override 
protected void onDestroy() 
{ 
    super.onDestroy(); 
    destroyed = true; 
} 

public void showLoadingProgressDialog() 
{ 
    context=Constant.getContext(); 
    this.showProgressDialog("Loading. Please wait..."); 
    Log.d("this",this.toString()); 
} 


public void showProgressDialog(CharSequence message) 
{ 
    if (progressDialog == null) 
    { 
     progressDialog = new ProgressDialog(this); 
     progressDialog.setIndeterminate(true); 
    } 

    progressDialog.setMessage(message); 
    progressDialog.show(); 
} 

public void dismissProgressDialog() 
{ 
    if (progressDialog != null && !destroyed) 
    { 
     progressDialog.dismiss(); 
    } 
} 
}

ActivityWeatherSetting.java：

public void initialize() 
    { 
     LayoutInflater layout = new LayoutInflater(Constant.getContext()) { 


     @Override 
     public LayoutInflater cloneInContext(Context newContext) { 
      return null; 
     } 
    }; 
    view=(View)layout.inflate(R.layout.activity_grid_layout, null); 
    boolean bResult = initializeData(); 

    if (bResult != false){ 
     bResult = initializeView(); 
    } 

    if (bResult == false){ 
     Log.e(TAG,"Init data failed"); 
     return; 
    } 
     drawWeatherScreen(); 
}  

private void updateDataOfCurrentLocation(){ 
    requestUpdateWeather(); 
} 
private void requestUpdateWeather(){ 
    Message msgFetchData = new Message(); 
    msgFetchData.what = REG_GET_WEATHER_START; 
    m_HandleRequest.sendMessage(msgFetchData);  
} 



private void initializeHandleRequest(){ 
    m_Runnable = new Runnable(){ 

     //@Override 
     public void run() { 
      requestUpdateWeather(); 
     }   
    }; 
    /* Setting up handler for ProgressBar */ 
    m_HandleRequest = new Handler(){ 
     @Override 
     public void handleMessage(Message message) { 
      int nRequest = message.what; 

      switch(nRequest){ 
      case REG_GET_WEATHER_START: 
       String strWOEID = m_Preferneces.getLocation(); 
       if (strWOEID == null){ 
        Log.e(TAG,"Can not get WOEID"); 
        //m_ProgressDialog.dismiss(); 
        //displayNotifyCation(R.string.strFetchFailed); 
        return; 
       } else { 
        //Get weather information 
        m_WeatherInfo = m_DataModel.getWeatherData(strWOEID);   
       } 

       Message msgRegSearch = new Message(); 
       msgRegSearch.what = REG_GET_WEATHER_FINISH; 
       sendMessage(msgRegSearch); 
       break; 

      case REG_GET_WEATHER_FINISH: 
       if (m_WeatherInfo != null){ 
        updateWeatherInfo(m_WeatherInfo); 
        //notifyUpdateTime(); 
       }     
       //m_ProgressDialog.dismiss(); 
       m_HandleRequest.postDelayed(m_Runnable, (ONE_MINUTE*m_Preferneces.getTimeUpdate())); 
       break; 

       default: 
        Log.e(TAG,"Can not handle this message"); 
        break; 
      } 
     } 
    };  
}  



private boolean initializeView(){ 
    m_TextLocation = (TextView)view.findViewById(R.id.weatherset_location_txtview); 
    m_Temperature = (TextView)view.findViewById(R.id.weatherset_temp_txtview); 
    m_Humimidy = (TextView)view.findViewById(R.id.weatherset_humidity_txtview); 
    m_Visibility = (TextView)view.findViewById(R.id.weatherset_visibility_txtview); 
    m_WeatherIcon = (ImageView) view.findViewById(R.id.weather_icon); 
    m_Date = (TextView)view.findViewById(R.id.dateTime); 

    if ((m_TextLocation == null) || (m_Temperature == null) || 
      (m_Humimidy == null) || (m_WeatherIcon == null) || 
      (m_Visibility == null) || (m_Date == null)){ 
     Log.e(TAG,"View init failed"); 
     return false; 
    } 

    return true; 
} 

private boolean initializeData(){ 
    /* Get application context */ 
    Context appContext = view.getContext(); 

    /* Get preference instance */ 
    m_Preferneces = WeatherPreferences.getInstance(appContext); 
    if (m_Preferneces == null){ 
     Log.e(TAG, "Get preference instance failed, check please"); 
     return false; 
    } 

    /* Get instance of data model */ 
    m_DataModel = WeatherDataModel.getInstance(); 
    if (m_DataModel == null){ 
     Log.e(TAG,"Can not get data model"); 
     return false; 
    } 

    initializeHandleRequest(); 

    return true; 
}  
private void drawWeatherScreen(){ 
    /
    updateDataOfCurrentLocation(); 
} 
private void updateWeatherInfo(WeatherInfo weatherInfo) 
{ 
    try 
    { 
    if (weatherInfo == null){ 
     Log.e(TAG,"Weather is null"); 
     return; 
    } 

    String strCode = weatherInfo.getCode(); 
    int nCode = getImageByCode(strCode); 
    m_WeatherIcon.setImageResource(nCode); 

    boolean bIsC = m_Preferneces.getTempFmt(); 

    String strFmt; 
    String strTemp = weatherInfo.getTemperature(WeatherInfo.TEMPERATURE_FMT_CELSIUS); 
    if (bIsC == true){ 
     strFmt = view.getContext().getString(R.string.str_temperature_fmt); 
    } else { 
     strFmt = view.getContext().getString(R.string.str_temperature_fmt_f); 
     strTemp = WeatherDataModel.convertC2F(strTemp); 
    } 

    //String strTemperature = String.format(strFmt, strTemp); 
    strTemperature = String.format(strFmt, strTemp); 

    m_TextLocation.setText(weatherInfo.getCity()); 
    m_Temperature.setText(strTemperature); 
    m_Date.setText(weatherInfo.getDate()); 

    TextView humidity=(TextView)view.findViewById(R.id.humidityValue); 
    TextView visibility=(TextView)view.findViewById(R.id.visiValue); 
    strFmt = view.getContext().getString(R.string.str_humidity_fmt); 
    String strHumidity = String.format(strFmt, weatherInfo.getHumidity()); 
    //m_Humimidy.setText(strHumidity); 
    humidity.setText(strHumidity); 
    strFmt = view.getContext().getString(R.string.str_visi_fmt); 
    String strVisi = String.format(strFmt, weatherInfo.getVisibility()); 
    //m_Visibility.setText(strVisi); 
    visibility.setText(strVisi); 
    } 
    catch(Exception e) 
    { 
     //Toast.makeText(ActivityWeatherSetting.this, e.getMessage(), Toast.LENGTH_LONG).show(); 
    } 
private int getImageByCode(String strCode){ 
    int nImageCode = R.drawable.a0; 

    if (strCode == null){ 
     Log.e(TAG,"Code is null"); 
     return nImageCode; 
    } 

    int nCode = Integer.parseInt(strCode); 

    int nNumber= YahooWeatherHelper.m_ImageArr.length; 
    for (int i=0; i < nNumber; i++){ 
     if (nCode == YahooWeatherHelper.m_ImageArr[i][1]){ 
      return YahooWeatherHelper.m_ImageArr[i][0]; 
     } 
    } 
    return nImageCode; 
}

異常在logcat中：

11-18 13:38:20.510: E/AndroidRuntime(585): FATAL EXCEPTION: AsyncTask #1 
11-18 13:38:20.510: E/AndroidRuntime(585): java.lang.RuntimeException: An error occured while executing doInBackground() 
11-18 13:38:20.510: E/AndroidRuntime(585): at android.os.AsyncTask$3.done(AsyncTask.java:278) 
11-18 13:38:20.510: E/AndroidRuntime(585): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273) 
11-18 13:38:20.510: E/AndroidRuntime(585): at java.util.concurrent.FutureTask.setException(FutureTask.java:124) 
11-18 13:38:20.510: E/AndroidRuntime(585): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307) 
11-18 13:38:20.510: E/AndroidRuntime(585): at java.util.concurrent.FutureTask.run(FutureTask.java:137) 
11-18 13:38:20.510: E/AndroidRuntime(585): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:208) 
11-18 13:38:20.510: E/AndroidRuntime(585): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076) 
11-18 13:38:20.510: E/AndroidRuntime(585): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569) 
11-18 13:38:20.510: E/AndroidRuntime(585): at java.lang.Thread.run(Thread.java:856) 
11-18 13:38:20.510: E/AndroidRuntime(585): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare() 
11-18 13:38:20.510: E/AndroidRuntime(585): at android.os.Handler.<init>(Handler.java:121) 
11-18 13:38:20.510: E/AndroidRuntime(585): at com.net.elderlyhealth.weather.ActivityWeatherSetting$3.<init>(ActivityWeatherSetting.java:384) 
11-18 13:38:20.510: E/AndroidRuntime(585): at com.net.elderlyhealth.weather.ActivityWeatherSetting.initializeHandleRequest(ActivityWeatherSetting.java:384) 
11-18 13:38:20.510: E/AndroidRuntime(585): at com.net.elderlyhealth.weather.ActivityWeatherSetting.initializeData(ActivityWeatherSetting.java:561) 
11-18 13:38:20.510: E/AndroidRuntime(585): at com.net.elderlyhealth.weather.ActivityWeatherSetting.initialize(ActivityWeatherSetting.java:137) 
11-18 13:38:20.510: E/AndroidRuntime(585): at com.net.elderlyhealth.weather.Task.doInBackground(Task.java:44) 
11-18 13:38:20.510: E/AndroidRuntime(585): at com.net.elderlyhealth.weather.Task.doInBackground(Task.java:1) 
11-18 13:38:20.510: E/AndroidRuntime(585): at android.os.AsyncTask$2.call(AsyncTask.java:264) 
11-18 13:38:20.510: E/AndroidRuntime(585): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305) 
11-18 13:38:20.510: E/AndroidRuntime(585): ... 5 more 
11-18 13:38:23.420: I/dalvikvm(585): threadid=3: reacting to signal 3 
11-18 13:38:23.561: I/dalvikvm(585): Wrote stack traces to '/data/anr/traces.txt' 
11-18 13:38:23.920: I/dalvikvm(585): threadid=3: reacting to signal 3 
11-18 13:38:24.032: I/dalvikvm(585): Wrote stack traces to '/data/anr/traces.txt' 
11-18 13:38:24.940: E/WindowManager(585): Activity com.net.elderlyhealth.view.ViewPagerFragmentActivity has leaked window [email protected] that was originally added here 
11-18 13:38:24.940: E/WindowManager(585): android.view.WindowLeaked: Activity com.net.elderlyhealth.view.ViewPagerFragmentActivity has leaked window [email protected] that was originally added here 
11-18 13:38:24.940: E/WindowManager(585): at android.view.ViewRootImpl.<init>(ViewRootImpl.java:344) 
11-18 13:38:24.940: E/WindowManager(585): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:267) 
11-18 13:38:24.940: E/WindowManager(585): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:215) 
11-18 13:38:24.940: E/WindowManager(585): at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:140) 
11-18 13:38:24.940: E/WindowManager(585): at android.view.Window$LocalWindowManager.addView(Window.java:537) 
11-18 13:38:24.940: E/WindowManager(585): at android.app.Dialog.show(Dialog.java:278) 
11-18 13:38:24.940: E/WindowManager(585): at android.app.ProgressDialog.show(ProgressDialog.java:116) 
11-18 13:38:24.940: E/WindowManager(585): at android.app.ProgressDialog.show(ProgressDialog.java:99) 
11-18 13:38:24.940: E/WindowManager(585): at android.app.ProgressDialog.show(ProgressDialog.java:94) 
11-18 13:38:24.940: E/WindowManager(585): at com.net.elderlyhealth.view.SampleGridTwoFragment$1.onItemClick(SampleGridTwoFragment.java:119) 
11-18 13:38:24.940: E/WindowManager(585): at android.widget.AdapterView.performItemClick(AdapterView.java:292) 
11-18 13:38:24.940: E/WindowManager(585): at android.widget.AbsListView.performItemClick(AbsListView.java:1058) 
11-18 13:38:24.940: E/WindowManager(585): at android.widget.AbsListView$PerformClick.run(AbsListView.java:2514) 
11-18 13:38:24.940: E/WindowManager(585): at android.widget.AbsListView$1.run(AbsListView.java:3168) 
11-18 13:38:24.940: E/WindowManager(585): at android.os.Handler.handleCallback(Handler.java:605) 
11-18 13:38:24.940: E/WindowManager(585): at android.os.Handler.dispatchMessage(Handler.java:92) 
11-18 13:38:24.940: E/WindowManager(585): at android.os.Looper.loop(Looper.java:137) 
11-18 13:38:24.940: E/WindowManager(585): at android.app.ActivityThread.main(ActivityThread.java:4424) 
11-18 13:38:24.940: E/WindowManager(585): at java.lang.reflect.Method.invokeNative(Native Method) 
11-18 13:38:24.940: E/WindowManager(585): at java.lang.reflect.Method.invoke(Method.java:511) 
11-18 13:38:24.940: E/WindowManager(585): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 
11-18 13:38:24.940: E/WindowManager(585): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 
11-18 13:38:24.940: E/WindowManager(585): at dalvik.system.NativeStart.main(Native Method)

我看到的AsyncTask問題，那麼那麼多的問題，但沒有幫助我。我需要幫助...

來源

2012-11-18 Abdul Rahman

您必須在doInBackground（）中執行ui操作。在onPreExecute和onPostExecute中執行同樣的操作。 – Raghunandan

@Raghunandan：那麼我將如何使用onPreExecute和onPostExecute呢？ –

http://developer.android.com/reference/android/os/AsyncTask.html。鏈接應該可以幫助你更好地理解asynctask – Raghunandan

的問題是，當你調用hh.initialize()，你已經在後臺線程，這是爲時已晚來創建Handler。事實上，你的代碼正在嘗試從後臺線程做很多UI的東西。您應該將UI線程之外需要完成的事情分離出來，並將其從AsyncTask的doInBackground中調用。

來源

2012-11-18 06:05:06

然後在我的情況下，我該如何實現它？ –

@AbdulRahman - 首先，我將爲ActivityWeatherSetting定義一個構造函數，並將Handler的創建移動到構造函數中。然後在'Task'中，我會將調用從'doInBackground'移動到'new ActivityWeatherSetting（）'到'onPreExecute'並保存在一個實例變量中。這將在UI線程上創建處理程序，並應該擺脫這種特殊的異常。如果在此之後遇到問題，請使用更新的代碼發佈另一個問題。祝你好運！ –

我爲'ActivityWeatherSetting'創建了一個構造函數，然後我在構造函數中創建了'Handler'，後來我在'onPreExecute'上調用'new ActivityWeatherSetting（）'，但仍然沒有得到解決方案，ProgressDialog仍在加載。 –

doInBackground過程中的問題

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