Start an Activity from a BroadcastReceiver with a

问题:

I can call an Activity from a BroadcastReceiver by this way:

public class AlarmReceiver extends BroadcastReceiver
{
    @Override
    public void onReceive(Context context, Intent intent)
    {
        try {
            Intent i = new Intent(context, MyActivity.class);
            i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            context.startActivity(i);

            Log.v(TAG, "alarm triggered");
        } catch (Exception e) {
            Log.v(TAG, e.toString());
        }
    }
}

This brings the app to the front and calls onResume() at the Activity. My problem is I can't determine if the BroadcastReceiver brought me to onResume() or just the user itself by hand. Is there any way I can be sure that the BroadcastReceiver called the Activity?

I also tried to fill the Intent at the BroadcastReceiver with Extras by doing i.putExtra("foo", "bar"). I couldn't read it out by calling MyActivity.getIntent().getExtras().get("foo") at the Activity.

Hope somebody can help me with this issue, thank you very much!

回答1:

You can send extras in your intent and check them onReceive but proper way of doing this would be to set a boolean value for "STARTED_BY_RECEIVER";

When starting the activity, throw the third line into your onReceive callback method;

Intent i = new Intent(context, MyActivity.class);
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
i.putExtra("STARTED_BY_RECEIVER", true);
context.startActivity(i);

Then in the onCreate of the activity, you can check if this was started by the broadcast receiver like this;

if(getIntent().getExtras() != null && getIntent().getExtras().getBoolean("STARTED_BY_RECEIVER")){
    // The activity was started by the receiver
}
else{
   // The activity was started by user

This would work because the getBoolean method would return false when there's no extra called "STARTED_BY_RECEIVER", this way you only have to put the flag in the one place (started by receiver)

Also don't forget to the put the "STARTED_BY_RECEIVER" in a static variable and use that in both places!

回答2:

Broadcast receivers cant pass extras http://developer.android.com/reference/android/content/BroadcastReceiver.html

You could try to do it in reverse though, have the user action of opening the activity pass a boolean set to true as default value the you can check for

boolean userStarted = getIntent().getExtras().getBoolean('userStarted', false);