In my app, whenever calling the finish() method, wherever it was, I am not taken to the previous activity, rather I am directed to mainActivity.
finish();
My aim is, showing the user the activity just before the current activity he is seeing.
Question 1 : How can I make finish() always take me to the activity before ?
Question 2 : Does this work using another workaround other than finish() ?
Question 3 : How to check the stack of activities and decide accordingly which one to go to ?
If you have written finish in each intermediate activity, that means you are removing the activity from the stack, hence on finishing an activity you are taken to the last non-finished activity, hence write finish() in only that activity which you do not want to see until the same workflow is followed and its onCreate() is called
if you start activity c from b and b from a if you use the back button on your phone at activity c it will go to b and back button press in b it will show a. if you use finish in all the 3 activities what happens is a calls b and a is finished and b calls c and b is finished so when you use finish in c it will not have b to show. so you have to tell where you are placing your finish based on some condition or a button click or just before starting a new activity, post your code and we will help you.
Related
I would like to ask similar question to:
Go back to previous screen without creating new instance
However I don't want Activity A go through onCreate callback, I would like to return to previous instance in the same state. How to achieve that without calling multiple finish() ?
There's no need to finish() activities as you navigate through your application. Instead, you can maintain your Activity back-stack and still achieve your goal. Let's say you have 4 activites like so:
A --> B --> C -->D
where D is the topmost activity and A is root activity. If you are 'falling back' to activity B, then you'll need to do two things in order to avoid hitting B's onCreate method.
1.) Make B a "SingleTask" activity. You can do this in the Android Manifest. To be brief, this means that only one 'instance' of B will ever exist within this Task. If B is already running when it's called then it will simply be brought to the front. This is how you do that.
<activity
android:name=".ui.MyActivity"
android:launchMode="singleTask"/>
But you don't want to just bring B to the front. You want to 'fall back' to B so that your stack looks like
A--> B
2.) Add this flag to your intent that 'starts' B. This ensures that C and D are removed.
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
Now when 'D' calls new Intent to B, B will be resumed and C and D will be removed. B will not be recreated, it will only call onNewIntent.
When navigating from A to B do not finish Activity A.
When navigating from B to C finish Activity B.
When navigating from C to D finish Activity C.
So from wherever you navigate back finish current Activity and Activity A will get resume again not get created.
I'm new to Android. My problem is:
Activity A calls activity B in the middle of its execution
Activity B must start and complete its execution
Only then activity A must resume (not restart)
Activity A has a loop. Somewhere in the middle of loop, Activity B is called, and once B finishes, A should resume the loop from where it left off.
I tried to code this, but what happens right now is that Activity A calls B, but B is not entered, then A resumes the loop and again calls B.
Essentially, the calls to B are stacked and once the loop in A completes, one by one the calls to B in stack are executed, so finally the first call to B is executed last in a last-in first-out order. I just want to execute B once, at the appropriate time.
Can anyone help me?
You are using the wrong design paradigm for your app. You should not start another activity like that. Keep the code on separate modules by all means, but do not start another activity just to transfer control.
Your activity will resume, when calling the Acticity B, don't finish Activity A. If you need to write some code when it resumes. you can do that by overriding onResume method of Activity A.
Take a look at Starting Activity for result. You can start Activity B for some result, and when Activity B finishes, the onActivityResult method of Activity A will be called and you can set it to continue/start work there.
EDIT
Based on your updated question you can try:
Create a method in Activity A which starts a loop
When you decide you want to call Activity B
2.1 Exit the loop, and save to where the loop is
2.2 Start Activity B for result
When Activity B finishes and returns you some kind of result, you will restart the loop (form the point you saved in step 2.1) in Activity A
I have a problem cause when I go to different activities using startActivity function,
they always get created from scratch. Even if activity A was visited before, when I go to activity B and then A again, activity A is created again.
The problem is with back button, cause if I go to Activity A then B then A and then B,
in order to close the application I have to press back button 4 times.
I guess that it shouldn't act like it and user should be able to go to activity A when first pressed back button and the second press should close the application.
How to solve this issue?
Greetings
If you have activity transitions like:
Activity A -> Activity B
Activity B -> Activity A
and you want the user to go back to the same instance of Activity A in this case, maybe you just need to call finish() in Activity B after you call startActivity() for Activity A?
If this isn't helpful, please give us more information about what you are trying to do.
make sure you implement onSaveInstanceState and be prepared to restore your activity from a Bundle in onCreate. that's how you re-establish where you were when you return to an activity.
add launcheMode="singleTask" to your activity in the manifest
You need to set FLAG_ACTIVITY_SINGLE_TOP to your intent for launching activity A. Doing so will cause your previously created activity to re-use. Make sure you do handle your afterwards intents in onNewIntent method. For more info.
You need to set the flag FLAG_ACTIVITY_REORDER_TO_FRONT when you start activity A from B or vice versa, like
i = new Intent("....ActivityAorB");
i.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
startActivity(i);
I've tried solutions proposed so far, however they didn't do it for me.
What did however, is using flag FLAG_ACTIVITY_CLEAR_TOP while starting activities.
Thanks for pointing me in the right direction though.
I have an application which consists 3 activities - lets call them A, B & C.
From activity A You can get to activity B, from B to C and from C to A (By pressing the back button).
On activity A I have an exit button (I know it`s not recomandded on android, but a lot of users are asking for it, so I decided to add it).
Anyway the problem is that: activity B has a timer, when the timer is finished it starts an intent that starts activiy C and calls finish() on activity B.
When the user then press back on activity C he gets to activty A - and then when he presses the exit button (this button only preforms finish()), it pops up activity B again. How can I prevent it from happen?
Thanks!
Idea: set a isFinished field in your Application to true and call finish(). All activities check if isFinished in their onResume() and if true they finish().
I'm not sure I understand how you end up at A when going back from C. Shouldn't it go back to B (logically, I mean. I know you want it to go to A)? In fact, that seems to kind of be what's happening. B is getting relaunched, but A appears on top of it, so that when you finish A, B (which was under it) is now shown.
It sounds like you don't want B to be part of the history stack, so maybe when you launch B, you should launch it with the no history flag.
You activity b is not finished thats what i can figure out it is still in running state so when all other actitivties are finished it shows up please chekc if it is finished or not
I have 2 activities. Activity A and Activity B. Both calling each other though intent. Activity A calls Activity B. Activity B accesses database and sends it back to activity A through putExtra() and getExtra().
Now my activity A is in declared like this android:launchMode="singleTask"
When I go back to activity A I want my this activity A to be updated or refreshed automatically. But to my wonder what I understood on debugging that if I declare an activity as launchMode="singleTask" then it just brings forth the screen to top from the stack. It does not actually go inside the code.
Is the concept what I understood correct ?
The solution I see is have a refresh button and on click of that access the code and update screen. But I do not want to do that. Do you think there is any other alternative ? I do not want to change launchMode="singleTask"
Thanks in Advance.
Try startActivityForResult(intent); and while you have finished in B setResult(RESULT_OK); and finish(); the B activity, and in A onActivityResult(int,int,intent); catch the result code if it is RESULT_OK update your A.
No matter which launchMode, when you switch from Activity B to Activity A, the onResume() method must be invoked. You can put your refresh code there to get your activity A updated.
put your refresh part in the onResume method .Once Activity B completed your onResume method will be invoked in Activity A.