在課堂上使用上下文擴展BroadcastReceiver

Question

當android中的鬧鐘響起時，我想創建一個AlertDialog。另外，我想創建一個通知，具體取決於用戶在對話框的單選按鈕中單擊的選項。 當我嘗試使用context或getApplicationContext()時出現問題。

這是我的代碼：

public void onReceive(final Context context, Intent intent) 
{ 
    final CharSequence[] items = {" I'm taking the dose now! "," Remind again in ten minutes. "," Ignore for now. "}; 
    String doseName = intent.getStringExtra("doseName"); 
    Toast.makeText(context, "Take medicine: " + doseName, Toast.LENGTH_LONG).show(); 

    AlertDialog.Builder builder = new AlertDialog.Builder(context); 
    builder.setTitle("It's time for your medicine."); 
    builder.setSingleChoiceItems(items, -1, new DialogInterface.OnClickListener() { 
     public void onClick(DialogInterface dialog, int item) { 
      switch(item) 
      { 
      case 0: 
       Toast.makeText(context, "Good.", Toast.LENGTH_SHORT).show(); 
       break; 
      case 1: 
       Toast.makeText(context, "Reminder set in ten minutes.", Toast.LENGTH_SHORT).show(); 
       break; 
      case 2: 
       Intent service1 = new Intent(context, DoseAlarmService.class); 
       service1.putExtra("doseName", doseName); 
       context.startService(service1); 
       break; 
      } 
     } 
    }); 
    levelDialog = builder.create(); 
    levelDialog.show(); 
} 

我一直在使用getApplicationContext代替context開關盒內試過了，但是這是確切的錯誤我得到：

The method getApplicationContext() is undefined for the type new DialogInterface.OnClickListener(){} 

如何任何建議前進？

編輯：

截至目前，這些是我已經試過：

public void onReceive(final Context context, Intent intent) 
{ 
     ctx = context; 
    final CharSequence[] items = {" I'm taking the dose now! "," Remind again in ten minutes. "," Ignore for now. "}; 
    String doseName = intent.getStringExtra("doseName"); 
    Toast.makeText(ctx, "Take medicine: " + doseName, Toast.LENGTH_LONG).show(); 

    AlertDialog.Builder builder = new AlertDialog.Builder(ctx.getApplicationContext()); 
    builder.setTitle("It's time for your medicine."); 
    builder.setSingleChoiceItems(items, -1, new DialogInterface.OnClickListener() { 
     public void onClick(DialogInterface dialog, int item) { 
      switch(item) 
      { 
      case 0: 
       Toast.makeText(ctx, "Good.", Toast.LENGTH_SHORT).show(); 
       break; 
      case 1: 
       Toast.makeText(ctx, "Reminder set in ten minutes.", Toast.LENGTH_SHORT).show(); 
       break; 
      case 2: 
       Intent service1 = new Intent(ctx.getApplicationContext(), DoseAlarmService.class); 
       service1.putExtra("doseName", doseName); 
       ctx.startService(service1); 
       break; 
      } 
     } 
    }); 
    levelDialog = builder.create(); 
    levelDialog.show(); 
} 

而且，而是採用ctx，我心中已經直接使用context.getApplicationContext()和檢查。它不起作用。

此外，當我註釋掉所有有問題的領域，只是運行，以驗證對話框輪番上漲，我得到這個異常：

07-23 13:26:21.316: E/AndroidRuntime(1756): java.lang.RuntimeException: Unable to start receiver com.dosemanager.ui.DoseAlarmReceiever: android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application 

請幫幫忙！

Answer 1

嗯，你已經有你的背景 - 這是onReceive()的參數。你不需要使用getApplicationContext()。

編輯：不能使用開關的情況下背景下，因爲背景是在接收器類中定義你想在onClickListener類使用它。 我的建議是：

public class %YOUR_RECEIVER_CLASS% { 
     private Context context; 
     public onReceive(Context context, ...) { 
      this.context = context; 
     } 
    } 

現在你可以使用上下文到處

Answer 2

使用getBaseContext（）而不是getApplicationContext（）

例如廣播接收器::

@Override 
    public void onCreate() 
    {   
     Toast.makeText(this, "SmsSenderService()", Toast.LENGTH_LONG).show(); 

     sendBroadcastReceiver = new BroadcastReceiver() 
     { 
       public void onReceive(Context arg0, Intent intent) 
       { 
       switch (getResultCode()) 
       { 
        case Activity.RESULT_OK:     

        Toast.makeText(getBaseContext(), "SMS Sent", Toast.LENGTH_SHORT).show();   

        break; 

       } 
      } 
     }; 

Answer 3

您正在嘗試從廣播接收器開始一個警告對話框，這是不允許的。看看這個：

show an alert dialog in broadcast receiver after a system reboot