The issues surrounding this have been discussed before here, but I have done a lot of poking around and wanted to report my findings and a workaround I have come up with to see if anyone has any thoughts on why this is happening and if my workaround has any holes in it.
What is happening: (This refers to an application that has not set any launchMode settings and so is using the defaults) 1. You launch an app from the Market or from the Installer. This launches the root/main activity of the application with the FLAG_ACTIVITY_NEW_TASK flag and no categories. Right now the applications stack is [ A ] 2. Then you proceed to the next activity in the application. Now the stack in this task is [ A > B ] 3. Then you press the home key and then relaunch the same application by pressing it's icon from either the home screen or the app tray. 4. What is expected at this point is that activity B will show, since that is where you left off. However A is shown and the tasks stack is [ A > B > A ] This second instance of A is launched with the following flags: FLAG_ACTIVITY_NEW_TASK, FLAG_ACTIVITY_RESET_IF_NEEDED, and FLAG_ACTIVITY_BROUGHT_TO_FRONT. It also has the android.intent.category.LAUNCHER category. At this point, if you hit the back key, it will return you to B, as it was when you left it. Looking at the documentation it seems as if FLAG_ACTIVITY_BROUGHT_TO_FRONT should only be set for activities that use the singleTask or singleTop launchModes. However, this application has not set any launchModes and is therefore using the default standard launchMode. I assume this is not suppose to happen in this case? So the workaround I am thinking of using is as follows. I came up with this because I do not want to have to ask for an extra permission (GET_TASKS) and have to loop through running tasks on every launch. In the main/root activity's onCreate method, check if the intent has the FLAG_ACTIVITY_BROUGHT_TO_FRONT set and if so, call finish(). This then pops the extra instance of A off the stack [ A > B > A ] becomes [ A > B ] and from the users perspective, it launches into the activity they were expecting. It seems to work in all of my tests so far. My only worry is that if there is some weird case where someones launcher would always flag a launch with FLAG_ACTIVITY_BROUGHT_TO_FRONT even if the app wasn't already in a task, and therefore would completely lock them out because it would call finish() and not have anything in the stack to return to. I should also note, that if the task is finished (restarting the phone, force stopping the app, or hitting back all the way through the stack) will fix this issue and will no longer launch it incorrectly. It only happens if you launch the app from the installer or market and then try to launch it from the launcher. So in summary, why is this happening? Is there a way to prevent it and if not, does my workaround have any problems you can see? Thanks much!! -- You received this message because you are subscribed to the Google Groups "Android Developers" group. To post to this group, send email to android-developers@googlegroups.com To unsubscribe from this group, send email to android-developers+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-developers?hl=en
