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How to keep layout and its data

I need your help, I have 2 activities A and B where A is the main activity.
Now B starts the activities from A using startActivityForResult() and from B when I finish it will go back to activity A.
This works fine but the actual purpose was like the Gmail application when you go back from B to A and then start activity B again from A, then A need to start activity with its last screen as i left it.
For example: from inbox->label->draft in gmail how to achieve this to keep data/layout as it is.

Maybe android:launchMode="singleInstance" on activity A and B will get it done?

How to switch Activity from 2 activities without losing its data and current state of data
Ok I have got solution that when every time start your application that time only activity will be created and view and put in stack so the next time you start again this activity just open from background so the activity will available in stack and just brought to front using start activity
From A to start ActivityB
Intent intent = new Intent(context,ActivityB.class);
intent.addFlags(Intent.FLAG_ACTIVITY_LAUNCHED_FROM_HISTORY);
intent.addFlags(Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT);
intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
startActivity(intent);
Now for start ActivityA from ActivityB
Intent intent = new Intent(getInstance(), ActivityA.class);
intent.addFlags(Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT);
intent.addFlags(Intent.FLAG_ACTIVITY_LAUNCHED_FROM_HISTORY);
intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
startActivity(intent);
It just brought front while activity start and put the current activity into background

Android:Delete a activity in backstack

I have got 4 activity let it be A->B->C->D.In every A,B,C activity user need to enter data all data will sent to server in C activity if the user data is correct he will move on to D activity and all the activity A,B,C removed from stack.If the data is in correct i need give the user to reenter data i.e is on back press it has to move C->B->A.My question is How to remove A,B,C activity when user enter D activity.

Use FLAG_ACTIVITY_CLEAR_TOP this shall solve your problem
From the Android documentation:
If set, and the activity being launched is already running in the
current task, then instead of launching a new instance of that
activity, all of the other activities on top of it will be closed and
this Intent will be delivered to the (now on top) old activity as a
new Intent.
For example, consider a task consisting of the activities: A, B, C, D.
If D calls startActivity() with an Intent that resolves to the
component of activity B, then C and D will be finished and B receive
the given Intent, resulting in the stack now being: A, B.
Use it like
Intent intent = new Intent(getApplicationContext(),
yourActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
and also, take a look at this question:
Activity with Flag FLAG_ACTIVITY_CLEAR_TOP (android)
Edit : I thought you want to move to your home activity from D and want to remove all activities from stack
Your stack would be like homeactivity , A , B , C , D
so i gave you this solution as this shall remove all activities in stack on top of your home activity.
If you want to clear the the stack while going to D, for that you can use FLAG_ACTIVITY_TASK_ON_HOME or FLAG_ACTIVITY_CLEAR_TASK
But both of these for api level 11.

The correct answer interesting for me also, but I can offer a solution:
For example you start activity A from O: O->A->B->C->D.
On activity O you can put in android manifest android:launchMode="singleTop"
Then, when data are ok, you can start activity O with flag "FLAG_ACTIVITY_CLEAR_TOP" - it remove from stack A,B,C and will be called method onNewIntent (Intent intent) http://developer.android.com/reference/android/app/Activity.html#onNewIntent(android.content.Intent) in O, where you can start activity D.

You can start activities with startActivityForResult, and call setResult from for example activity D, in C activity you can listen activity result, and related of this result finish activity or not, or call setResalt from C activity ...

When you want to move D activity there you need to check your
conditions and if your condition is satisfied then you need to enter
into your Next activity(i.e., D) .In that case you need to use the
following code..
Intent intent = new Intent(this,D.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(intent);
Suppose In on backpress you need to use finish(). to move back i.e., C
-> B -> A.

Try this piece of code with some modifications:
Intent intent = new Intent(this, D.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP); // To clean up all activities
startActivity(intent);

Try looking for Activity's public method startActivity(Intent i) and finish() here
In usage wise, it should look like this.
Intent i = new Intent(MainActivity.this, MainActivity.class);
startActivity(i);
finish();
Hope this helps :D

Go back to previous screen without creating new instance

As explained in image, flow is something like this. So whenever user click on logo button Activity A should be called. As simple solution we can use this method...
Intent intent = new Intent(activity, activityToStart);
startActivity(intent);
But this activity will create a new activity for my app. but I need to call the same instance of the activity as we move forward in flow diagram. from Activity A to B and then again on B can be called easily by callingfinish() but from Activity C or D, how to come back to A.
I am running out of ideas but not getting any fruitful result. Please help me if you have any suggestion or at any place i am going wrong. Thanks in advance.

To Come Back from D to A, use Intent Flags.
Intent intent = new Intent(activity, activityToStart);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP)
startActivity(intent);
FLAG_ACTIVITY_CLEAR_TOP, will instead of creating new activity, it will invoke the activity on the stack, and will pop all the activities over the activity being invoked.

Instead of Using
Intent intent = new Intent(activity, activityToStart);
startActivity(intent);
Use
Intent intent = new Intent(activity, activityToStart);
startActivityforResult(intent,1234);
This will make Sure that The Activity A is not Killed and when You finish Your Activity C,Activity A will get Resumed.
Note :- Whenever You create A new Activity,without finishing(Exiting) the Host Activity,The Host Activity is Saved On the Stack in LIFO order
LIFO:- Last In First Out

By making Activity A a "SingleTask" you can achive this. When a Activity is in the SingleTask on clicking the Home button the other activites will be removed from the stack.
Refer these link's for more info on Android Activites...
Link 1 - Android Fundamentals
Link 2 - Another Similar Question

Use ViewFlipper to go and back between different window in the same activity.
ViewFlipper vf = (ViewFlipper) findViewById( R.id.view_flipper);
To go to the next window
vf.showNext();
To go to the previous window
vf.showPrevious();

I am not sure,this is right way or not,but you can give it a try!
You can finish() current activity when you open the new one starting from Activity-B.
i.e.
To open Activity-C => finish Activity-B and start Activity-C
To open Activity-D => finish Activity-C and start Activity-D
now when you will press back,Activity-A will open.

finish() activity twice in android?

Okay say your using a app, and you opened a new activity and then opened another, you can end the activity your on by using finish(); and your back one activity, but how can you go back two activities, all the way back to the first one? I know you could use:
Intent savedGameIntent = new Intent(v.getContext(), firstclass.class);
v.getContext().startActivity(savedGameIntent);
But is that the best way to do it?

Use the flag Intent.FLAG_ACTIVITY_CLEAR_TOP.
Intent intent = new Intent(this,A.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
From the documentation:
If set, and the activity being launched is already running in the current task, then instead of launching a new instance of that activity, all of the other activities on top of it will be closed and this Intent will be delivered to the (now on top) old activity as a new Intent.
So effectively, if you have A -> B -> C, and you intent to A with that flag set, B and C will close.

I believe that will start a new activity, not back up to the original one. It sounds like you want to finish the last and middle activities. If you start the last activity with startActivityForResult, you can then override onActivityResult in the middle activity, and call finish() from there.

How to finish all child activities from parent in android [duplicate]

I'm new to android. Actually one handler is running in Home Activity A for every 30 sec to check the net connection.
If I'm went to activity C by A->B->C, If there in no net connection at that time, then i want to close Activity B and C, then want to show message box in Activity A.
But My problem is My handler is running for every 30 sec in Home Activity A. But If i was in Activity C or some other Activity how to find which activity is my Application currently focussed now. Then i want to finish those child activities and want to show Home Activity A I have some 9 child activities in Activity B.
I heard about using "FLAG_ACTIVITY_CLEAR_TOP" . I used the code as follows in the handler in Home activity A itself. But got error.
Intent intent = new Intent( ctx, Homepage.class );
intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP |
Intent.FLAG_ACTIVITY_CLEAR_TOP);
ctx.startActivity( intent );
Here Homepage.class is my Home Activity A and i set that activity in manifest file as
android:launchMode="singleTop"
Please help!

You can start Activity A and close all other activities.
You have to create new intent and add flag FLAG_ACTIVITY_CLEAR_TOP
Intent activityA = new Intent(context, ActivityA.class);
activityA.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
context.StartActivity(activityA);
this will close all activities that are in the stack and are at the top of activity A

When calling Acitivity C, call finish in activity B , when calling Activity A from C , call finish() in activity C !

You can use, According to me two ways,
If you start an activity using startActivityForResult, then you can call finish() in this new Activity when you're done with it and it will return control to the activity that started it.
OR otherwise, May be I am wrong,
Call finish inside onStop 'override method'.

make a uniform resultCode for closing child activities. Eg. you make 911 (should be int) as your resultCode. If you want your Activity to finish and go back directly to parent Activity, you set the resultCode to 911:
setResult(911); finish();
In every child activity, you override the onActivityResult and check if the resultCode is 911. If yes, then call the setResult(911); finish(); until you get back to your parent activity. Hope this helps!

For example, if you want to start intentB, you can do following in old activity:
Intent intentB = new Intent();
intentB.setClass(XYZ.this, abc.class);
intentB.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intentB);