带有startActivityForResult的android launchMode singleTask

Question

We have a requirement to force the user to set up a password the first time he/she starts the app. So we have our main activity with launchMode=singleTask which start a password setting activity using startActivityForResult .

We also want the user to go back to their home if he/she taps back from the password setting page so we put the code to finish the main activity in its onActivityResult if it receives RESULT_CANCELLED . However, if the user taps home and re-enter our app, we want to show the password setting page again. But in this case, it will be destroyed (because main activity's launchMode is singleTask ) and also returns RESULT_CANCELLED to our main activity causing it to be finished.

So the problem is from main activity, we cannot distinguish between tapping back and tapping home then re-enter the app.

Is there anyway to fulfill this requirement while still keeping the launchMode as singleTask ?

Answer 1

onBackPressed() for tapping back

Called when the activity has detected the user's press of the back key. The default implementation simply finishes the current activity, but you can override this to do whatever you want.

http://developer.android.com/reference/android/app/Activity.html#onBackPressed%28%29

&& onPause() for home screen

(though it can be due to other things also like your next activity or switching to another application) http://developer.android.com/reference/android/app/Activity.html#onPause%28%29

Update :

Why Don't you use Sharedpreferences and check if the app is run for the first time and password/rest fields are set rather than using the approach you are using right now .

Answer 2

I had a very similar issue recently.

What I would suggest is that you don't actually finish the app when you get the RESULT_CANCELLED .

Instead do something like:

protected void onActivityResult(int requestCode, int resultCode, Intent intent) {   

    if (resultCode == Activity.RESULT_CANCELED) {

        if (/*TEST IF A USER IS SIGNED IN*/) {

            //IF SIGNED IN PROCEED TO MAIN ACTIVITY
        }
    // OTHERWISE FORCE THEM TO SIGNIN/REGISTER/WHATEVER AGAIN 
    // WITH ANOTHER CALL TO startActivityForResult
    ...

This is a back of an envelope approach to your problem, but this pattern has worked for me.

For me, my Authentication/Registration is all done in an Abstarct Class that extends Activity . Each of my activities then extends this class. I Place the Auth/Reg method calls in the onResume() of this Abstarct Class .

When a startActivityForResult is launched in the onResume() method and fails I don't finish() the activity but just let the app proceed and let the class handle which Reg/Auth form to present. Which it will do by checking various flags to determine what action it is meant to be performing.

The added benefit of this approach is that each and every Activity that might extend this abstract class gets the added benefit of a security check each time it is used.