Calling startActivity() from outside of an Activity?

user_355663 0
Viewed 225141

I'm using an AlarmManager to trigger an intent that broadcasts a signal. The following is my code:

AlarmManager mgr = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
Intent i = new Intent(this, Wakeup.class);
try
{
    PendingIntent pi = PendingIntent.getBroadcast(this, 0, i, 0);
    Long elapsed +=  // sleep time;
    mgr.set(AlarmManager.RTC_WAKEUP, elapsed, pi);
}
catch(Exception r)
{
    Log.v(TAG, "RunTimeException: " + r);
}

I'm calling this code from an Activity, so I don't know how I could be getting the following error...

ERROR/AndroidRuntime(7557): java.lang.RuntimeException: Unable to start receiver com.wcc.Wakeup: android.util.AndroidRuntimeException: Calling startActivity() from outside of an Activity  context requires the FLAG_ACTIVITY_NEW_TASK flag. Is this really what you want?
runtimeexception android-pendingintent alarmmanager android
11 Answers

For Multiple Instance of the same activity , use the following snippet,

Note : This snippet, I am using outside of my Activity. Make sure your AndroidManifest file doesn't contain android:launchMode="singleTop|singleInstance". if needed, you can change it to android:launchMode="standard".

Intent i = new Intent().setClass(mActivity.getApplication(), TestUserProfileScreenActivity.class);  
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_MULTIPLE_TASK);

// Launch the new activity and add the additional flags to the intent
mActivity.getApplication().startActivity(i);

This works fine for me. Hope, this saves times for someone. If anybody finds a better way, please share with us.

user_3841930

Android Doc says -

FLAG_ACTIVITY_NEW_TASK requirement is now enforced

With Android 9, you cannot start an activity from a non-activity context unless you pass the intent flag FLAG_ACTIVITY_NEW_TASK. If you attempt to start an activity without passing this flag, the activity does not start, and the system prints a message to the log.

Note: The flag requirement has always been the intended behavior, and was enforced on versions lower than Android 7.0 (API level 24). A bug in Android 7.0 prevented the flag requirement from being enforced.

That means for (Build.VERSION.SDK_INT <= Build.VERSION_CODES.M) || (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) it is mandatory to add Intent.FLAG_ACTIVITY_NEW_TASK while calling startActivity() from outside of an Activity context.

So it is better to add flag for all the versions - 

...
Intent i = new Intent(this, Wakeup.class);
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
...
user_33020260

I just want to notice that startActivity from outside an activity is valid in some android versions (between N and O-MR1) and the interesting point is that it is a bug in android source code!


This is the comment above startActivity implementation. See here.

Calling start activity from outside an activity without FLAG_ACTIVITY_NEW_TASK is generally not allowed, except if the caller specifies the task id the activity should be launched in. A bug was existed between N and O-MR1 which allowed this to work.

user_27002390

This same error I have faced in case of getting Notification in latest Android devices 9 and 10.

It depends on Launch mode how you are handling it. Use below code:- android:launchMode="singleTask"

Add this flag with Intent:- intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

user_25188260

In my case I have used context for startActivity, after changing that with ActivityName.this . it solves. I'm using method from util class so this happens.

Hope it help some one.

user_69261680

Here's the code. I have implemented it in a wallpaper api implementation app. In my app specifically when user click on a wallpaper image it will revert it on full screen view.

holder.imageView.setOnClickListener {
          val i = Intent(context,FullScreenWallpaper::class.java)
          i.putExtra("raheel", wallpaperModelList2[position])
          i.flags = Intent.FLAG_ACTIVITY_NEW_TASK
          context.startActivity(i)
      }
user_194413800
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