So I have an abstract class extended through the entire app that overrides the back key to reorder Activity A to the front (With the flag).
So, it would be:
A > B > anywhere, and the back key should bring me back to A
I'm using the FLAG_ACTIVITY_CLEAR_TOP, but it is entirely refreshing A for some reason and I don't want that.
So: Flag_activity_clear_top is reloading the onCreate() rather than onResume(). What gives?
If you want the activity to just be brought to the top without restarting it set the launchMode of the activity to singleTop in the manifest. You will receive a call to onNewIntent when the activity is being brought to the top. onNewIntent is called before onResume. If you only want this behavior for the specific intent you can add the FLAG_ACTIVITY_SINGLE_TOP(in addition to FLAG_ACTIVITY_CLEAR_TOP) to the intent with the addFlags call instead of the manifest.
Intent intent = new Intent(CurrentActivity.this, ActivityNeedOnTop.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
startActivity(intent);
CurrentActivity.this.finish();
From the API docs for FLAG_ACTIVITY_CLEAR_TOP
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.
**The currently running instance of activity B in the above example
will either receive the new intent you are starting here in its
onNewIntent() method, or be itself finished and restarted with the new intent.**
So I think your activity is itself finished and restarted.
Related
Suppose I start with Activity A which invokes Activity B. So the Task looks like A->B with B at the top.
B sends an intent to start Activity C and after sending the intent to C, B invokes finish() on itself. So the stack would look like A->C.
Now when I was sending an intent to Activity B with the flag FLAG_ACTIVITY_NEW_TASK, I noticed its onCreate() wasn't called. But when I added the flag FLAG_ACTIVITY_CLEAR_TOP along with the aforementioned one, it worked.
2 questions:
Why didn't it work with just FLAG_ACTIVITY_NEW_TASK ?
What changed with FLAG_ACTIVITY_CLEAR_TOP ?
I have gone through the official documentation of both the flags but cannot co-relate the explanation with the above scenario.
I have 3 activity . Activity A ,Activity B, Activity C.
This is the flow A->B->C.
Now i want to come to activity A from C .(i.e C->A) without getting its onCreate() called of Activity A.
so far my code is:But it will call onCreate() of ActivityA.
I want to call Restart().
Intent intent=new Intent(ActivityC.this,ActivityA.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
finish();
Two cases:
If you want to keep other activities live and just want to bring A to front, just use intent flag FLAG_ACTIVITY_REORDER_TO_FRONT.
If you don't want to clear all activities and want existing instance of A at top, then use intent flags FLAG_ACTIVITY_CLEAR_TOP and FLAG_ACTIVITY_SINGLE_TOP.
Note : If you use only FLAG_ACTIVITY_CLEAR_TOP, then onCreate will be called.
Keep android:launchMode="singleTask" in manifest at activity declaretion
An Activity with singleTask launchMode is allowed to have only one instance in the system
If instance already exists, i will not call 'onCreate' it will call 'onNewIntent' method.
See http://androidsrc.net/android-activity-launch-mode-example/ for better understand about launch modes.
Although setting the launch mode to singleTask will work, use of that launch mode is discouraged. The documentation for launch mode indicates singleTask is "not recommended for general use".
The desired behavior can be achieved using Intent flags FLAG_ACTIVITY_CLEAR_TOP and FLAG_ACTIVITY_SINGLE_TOP:
Intent intent=new Intent(ActivityC.this,ActivityA.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
startActivity(intent);
finish();
Activity A will not be recreated and will receive the intent via onNewIntent().
Use SingleTask launch mode for Activity A.
New intent will be delivered to existing instance.
I am having 3 activities. From the third activity, I need to come back to the 1st activity when a GUI button is clicked. I know I can click the "physical" back button 2 times to make this but that is not an option.
So, is there any way I can display the 1st activity, without creating a new instance? I can pass the 1st activity's instance to the third activity, no issue with that.
Use the FLAG_ACTIVITY_CLEAR_TOP in your intent.
From the documentation:
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.
To use:
Intent intent = new Intent(getBaseContext(), FirstActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
Intent intent = new Intent(src_ctxt, dest.class);
intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP | Intent.FLAG_ACTIVITY_CLEAR_TOP);
src_ctxt.startActivity(intent);
This should do it
I think you need to make your activity B singleInstance that if it's already create you don't want to create again, that is launch mode of the activity can be defined in manifest android:launchMode that defines how the activity will be instanciated.
in your case use android:launchMode="singleInstance"
or
You can use flag Intent.FLAG_ACTIVITY_NEW_TASK. If the activity is already running it will bring that to front instead of creating new activity.
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
I think I've just found a really strange bug... But it can just be somekind of feature that I never heard of.
On my application if I have any Activity on the AndroidManifest with android:launchMode="singleInstance" when you try to "clean" the stack to a certain point with the following code:
Intent intent = new Intent(this, Xpto.class);
intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP
| Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
It goes to that activity. But when you press back, it returns to the previous.that should have been finished...
Example:
A -> B -> C
Then from C I call A with Intent.FLAG_ACTIVITY_SINGLE_TOP| Intent.FLAG_ACTIVITY_CLEAR_TOP having A singleInstance on the Manifest. It goes to A but it only brings it to front. And does not finishes C and B.
Can somebody explain this behaviour?
The Xpto class I'm calling is at the time the root activity of the stack.
from reading this thread:
http://groups.google.com/group/android-developers/browse_thread/thread/5eb400434e2c35f4
it seems that:
"The currently running instance of activity B in the above example will
either receive the new intent you are starting here in its onNewIntent()
method, or be itself finished and restarted with the new intent. If it
has declared its launch mode to be "multiple" (the default) and you have
not set FLAG_ACTIVITY_SINGLE_TOP in the same intent, then it will be
finished and re-created; for all other launch modes or if
FLAG_ACTIVITY_SINGLE_TOP is set then this Intent will be delivered to
the current instance's onNewIntent(). "
which means that you need to set your launchMode to multiple instance, and use only FLAG_ACTIVITY_CLEAR_TOP.
Intent intent = new Intent(this, Xpto.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
In the scenario you described, activity's B and C are not finished when you start activity A (which is the root activity). The documentation describes that with launch mode of singleInstance and the flag FLAG_ACTIVITY_SINGLE_TOP set, activities B and C will NOT be finished. If you want to have activities B and C finished, then you must set the launch mode to multiple instance and NOT set the flag FLAG_ACTIVITY_SINGLE_TOP.