Question

当android中的警报响起时，我想创建一个AlertDialog。此外，我想创建一个通知，具体取决于用户在对话框上的单选按钮中单击的选项。当我尝试使用context或getApplicationContext()时会出现问题。

这是我的代码：

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();
}

我尝试在切换案例中使用getApplicationContext而不是context，但这是我得到的确切错误：

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

有关如何前进的任何建议吗？

修改

直到现在，这些都是我尝试过的：

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();
}

此外，我没有使用ctx，而是直接使用context.getApplicationContext()并进行了检查。它不起作用。

此外，当我注释掉所有有问题的区域并运行以验证对话框是否出现时，我会遇到以下异常：

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

请帮忙！

Answer 1

嗯，你已经有了你的上下文 - 它是onReceive()的参数。您无需使用getApplicationContext()。

编辑：你不能在switch case中使用context，因为在Receiver类中定义了context并且你试图在onClickListener类中使用它。我建议这个：

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

现在你可以在任何地方使用上下文

Answer 2

您正尝试从广播接收器启动警报对话框，这是不允许的。看看这个：

show an alert dialog in broadcast receiver after a system reboot

Answer 3

使用getBaseContext（）而不是getApplicationContext（）

示例BroadcastReceiver ::

 @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;

                }
            }
        };

在扩展BroadcastReceiver的类中使用上下文

3 个答案: