In my app, I have 5 activity. A(Main Activity),B,C,D,E.
At present, sometimes when Activity D is kept on background(onPause() / recent menu) for long time(30 min , or even 2 hours), when coming back the activity D is recreating itself (onCreate()). I don't want this to happen.
I want that App should resumed/relaunch to Activity A when opened from a background/recent menu screen after a long time.
Please advice what to do? Should i use handler with countdown to finish the activity.
Related
I have an application which has two activities A and B. When application is installed and run for the first time then it always starts with A as it is declared as launcher activity in manifest.
According to workflow, after a few seconds, activity A is destroyed and activity B is started. So that, the root of task becomes B. Now, when user presses the home button and later comes to our app, activity B is resumed as expected. But, if application is left in background for a long time then the application is restarted as from the logs Application::onCreate() is called. However, I want that whenever the application restarts that is whenever Application::onCreate() is called (like in the second case) activity A should be started instead of B, in all other cases when application is not restarted activity B should be appearing. I am new to android and unable to figure out a solution. Any help is much appreciated.
Thanks in advance.
Use SharedPreferences : http://developer.android.com/reference/android/content/SharedPreferences.html
In the end of your activity A you should create a preference that save the a state of your app in the SharedPreference.
at the start of onCreate() of your activities check the state and start the correct activity.
I have an activity A. now i start a service using
startService(new Intent(A.this,Service.class));
now after some times (since it is performing some task in background , you can move anywhere in phone , so lets stay at phone home screen) service stops and start an another activity B (now B is on Top) which show result. Current i am on screen B. my problem is when i am on B and press back , it does not show activity A. even if i exist from app(through back button) and again I launch the app it show activity B. since my starting activity is A so i want to show A not B. please guide me how can i do this.
I have activities in sequence as Activity A calling Activity B,When I am on Activity B I press Home button and start another Application (for example Map). If i stay on this second application for a long time say 5-10 minutes and then press Home Button again and choose to Start my application again, then Activity B is started again and works fine. But when i Press Back key - I return to my Activity A again (which is also correct) but it shows a Blank Screen. Ideally in correct version it should show me Acitivty A with the XML data is ListView form.
Alternatively, in the above description, when the other Map Application is started and if the user stay on it only for 1-2 minutes then the above problem doesnt not occur.
Can anyone suggest a solution on the same.
Is it that i need to check in Activity B whether Activity A is still there in Activity Stack (How do i do the same) and If its not in my Activity stack then re-create it.
I tried doing alwaysRetainTaskstate in my Android manifest file for Activity A. But it doesnt work at all
You don't have to do any of that, Android takes care of the technicalities for you - it will recreate your Activity A.
You just need to remember to save A's state when B is opened (take a look at Activity.onSaveInstanceState). When A is restarted, your saved state will be passed to onCreate.
You should really read about Activity Lifecycle
This should help.
I have a home screen widget with a button with a pendingIntent. Click it, it bundles a boolean to indicate where it came from and it brings up my main activity.
In my main activity in onCreate, I check for a bundle, if the boolean that says it was launched from my widget is true, I perform an action.
Every time I hit my widget button, it should launch my main activity, and run through onCreate.
And it does, on the emulator. And it did, on my n1. Then suddenly it stopped on my n1. I can still get it to hit onCreate when I launch from the widget but I have force stop or reinstall and then it only does it the first time.
What is going on with this?
What's going on is the Activity lifecycle. Android will keep the same instance of your Activity around so that the user can return to it later. Monitor some of the other lifecycle methods like onStart and onResume to see this in action.
You may see a difference in behavior if the user hits the back button vs. the home button. The back button will finish the current Activity by default, whereas home will leave it alone unless Android decides to kill it for resources later.
i have the following question.
I have an activity which is showing a progress bar while a service is downloading data from an API.
I want that when i press Home and relaunch my program the activity and which is not the first activity called but it is in the stack was recovered in order to continue showing the progress.
I have read about the cycle of life of activities but i don't find a clear solution.
The same thing happens If i am in the activity which is showing the progress bar and i press a button that takes me to another activity, when i go back, can i recover the old activity instead launch one new?
Anyone helps me?
Thanks
The problem is that pressing the home button will erase the whole activity stack. That means there is no possibility to go back to the activity it even is not certain that the activity still exists.
If this a progress that is interesting for the user that it is still running you could display a notification bar icon until the progress is finished. I think you can specify a special intent for clicking on the notification bar and filter this intent with your activity. That way you would go back to the activity. But you still face the problem that the activity is saved and has no reference to the background thread doing the work.
If your Activity has left the stack its finish method is called. You shouldn't try to reuse this activity later on. The best way is to think of a way that the whole state of the activity can be saved and restored later on. To restore a reference to the background thread doing the work you could subclass the application class and save a reference to the running task in your subclass.