android - 系统重新启动后在广播接收器中显示警报对话框

Question

您好，我正在尝试在广播接收器中显示系统重新启动后的警报对话框。我已在 list 中添加了接收者并调用了所需的权限，但在显示对话框时出现错误。请问我该如何正确实现？..谢谢

我的代码:

public void onReceive(final Context context, Intent intent) {
    Log.d(TAG, "received boot completed broadcast receiver... starting settings");


    String settings = context.getResources().getString(R.string.restart_setting);
        String yes = context.getResources().getString(R.string.Settings);
        String no = context.getResources().getString(R.string.Cancel);

              final AlertDialog.Builder builder = new AlertDialog.Builder(context);
                builder.setMessage(settings)
                       .setCancelable(false)
                       .setPositiveButton(yes, new DialogInterface.OnClickListener() {
    public void onClick(@SuppressWarnings("unused") final DialogInterface dialog, @SuppressWarnings("unused") final int id) 
   Intent config = new Intent(context, WeatherConfigure.class)
     context.startActivity(config);

    }
 })
    .setNegativeButton(no, new DialogInterface.OnClickListener() {
        public void onClick(final DialogInterface dialog, @SuppressWarnings("unused") final int id) {
             dialog.cancel();
        }
    });
  final AlertDialog alert = builder.create();
  alert.show();

    }

我收到此日志错误:

01-07 01:42:01.559: ERROR/AndroidRuntime(2004): Caused by: android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application

01-07 01:42:01.559: ERROR/AndroidRuntime(2004): at android.view.ViewRoot.setView(ViewRoot.java:548)

01-07 01:42:01.559: ERROR/AndroidRuntime(2004):at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:177)

01-07 01:42:01.559: ERROR/AndroidRuntime(2004): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91)

01-07 01:42:01.559: ERROR/AndroidRuntime(2004):at android.app.Dialog.show(Dialog.java:288)

01-07 01:42:01.559: ERROR/AndroidRuntime(2004):at com.MuaaApps.MyWeatherUpdate.myWeatherBroadcastReceiver.onReceive(MyWeatherBroadcastReceiver.java:59)

01-07 01:42:01.559: ERROR/AndroidRuntime(2004): at android.app.ActivityThread.handleReceiver(ActivityThread.java:1994)

Answer 1

问题是您试图显示来自 BroadcastReceiver 的 AlertDialog，这是不允许的。您不能显示来自 BroadcastReceiver 的 AlertDialog。只有 Activity 才能显示对话框。

您应该做其他事情，让 BroadcastReceiver 像您一样在启动时启动，并启动一个 Activity 来显示对话框。

这里是 blog post更多信息。

编辑:

这是我推荐的做法。从你的 BroadcastReceiver 开始一个 Activity 和一个 AlertDialog 像这样..

public class NotifySMSReceived extends Activity 
{
    private static final String LOG_TAG = "SMSReceiver";
    public static final int NOTIFICATION_ID_RECEIVED = 0x1221;
    static final String ACTION = "android.provider.Telephony.SMS_RECEIVED";

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

        IntentFilter filter = new IntentFilter(ACTION);
        this.registerReceiver(mReceivedSMSReceiver, filter);
    }

    private void displayAlert()
    {
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setMessage("Are you sure you want to exit?").setCancelable(
            false).setPositiveButton("Yes",
            new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int id) {
                    dialog.cancel();
                }
            }).setNegativeButton("No",
            new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int id) {
                    dialog.cancel();
                }
            });
        AlertDialog alert = builder.create();
        alert.show();
    }

    private final BroadcastReceiver mReceivedSMSReceiver = new BroadcastReceiver() {

        @Override
        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();

            if (ACTION.equals(action)) 
            {
                //your SMS processing code
                displayAlert();
            }
        }
    }
}

正如您在此处看到的，我从未调用过 setContentView()。这是因为 Activity 将具有透明 View ，并且只会显示警报对话框。