how can i call an activity from stack instead of launching new instance ?
here is a scenario :
calling activity A with parameters in order to retrieve data
navigate from A to B
navigate from B to C
i want launch A again but not with a new instance , i want get it from the stack so no need to pass parameters and wait to retrieve data.
If I get your point correctly you can simple exit your activity B and C with finish();.
So if you ActivityC finishes and also ActivityB the ActivityA should come to the front, which should be that what you want.
Try to use FLAG_ACTIVITY_REORDER_TO_FRONT. For example:
Intent intent = new Intent(BActivity.this, AActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
startActivity(intent);
From javadocs:
public static final int FLAG_ACTIVITY_REORDER_TO_FRONT
Added in API
level 3
If set in an Intent passed to Context.startActivity(), this flag will
cause the launched activity to be brought to the front of its task's
history stack if it is already running.
For example, consider a task consisting of four activities: A, B, C,
D. If D calls startActivity() with an Intent that resolves to the
component of activity B, then B will be brought to the front of the
history stack, with this resulting order: A, C, D, B. This flag will
be ignored if FLAG_ACTIVITY_CLEAR_TOP is also specified.
Related
I don't understand how to do my use case between the launchmode of activity and the flag of intent.
What i want to do :
A => B => C => B when i back B => C => A
In other word, i want to have a single instance of all activity in the stack and if i recall one of the single instance the activity go to top of stack (with reset or destroy + recreate don't have importance, id o my logic of creation in onresume so), exception for my custom splashscreen (but i resolve this one with noHistory for this activity "splashscreen").
I tried standard mode with flag
Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP or with this flag Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_REORDER_TO_FRONT but that don't have the behavior that i want.
So if you can tell me which launchmode and/or flag i should use for made what i want, i would be grateful.
FLAG_ACTIVITY_REORDER_TO_FRONT seems appropriate in your case:
FLAG_ACTIVITY_REORDER_TO_FRONT
If set in an Intent passed to Context.startActivity(), this flag will cause the launched activity to be brought to the front of its task's history stack if it is already running.
For example, consider a task consisting of four activities: A, B, C, D. If D calls startActivity() with an Intent that resolves to the component of activity B, then B will be brought to the front of the history stack, with this resulting order: A, C, D, B. This flag will be ignored if FLAG_ACTIVITY_CLEAR_TOP is also specified.
If we leave out Activity D in the above description we get:
A, B, C (start B) => A, C, B
Which appears to be what you want.
I have activities A -> B -> C -> D. How can I open the existing B from activity D clearing C and D? I would end up with A -> B. I don't want to recreate a new B.
I think you must use FLAG_ACTIVITY_CLEAR_TOP and FLAG_ACTIVITY_SINGLE_TOP.
According to the doc:
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. 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().
You can declare you target activity's(Activity B in your situation) Mode of SingleTop in Manifest file like
<activity android:name="YourActivityName" android:launchMode="singleTop"></activity>
Then startActivity for navigating to this Activity will end C and D and wont start a new Activity B
Right after you finish dealing with C and D, you can just finish() the activities.
I need to do the following: I have 5 activities and I call them like this A->B->C->D->E but when activity E finishes, then it should return to activity B keeping A first, like this: A->B. How can I do that? Thanks
You want FLAG_ACTIVITY_CLEAR_TOP:
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.
Don't create a new task.
Supposing I have the following activities:
Activity A
Activity B
Activity C
Activity D
A calls B, B calls C and C calls D, so my stack is, from top to bottom, D-C-B-A.
Now I want call from D the activity B in order to obtain the following stack:
B-A
Where B is not the previous instance that was in the initial stack configuration (D-C-B-A) but is a new instance.
What FLAG_ACTIVITY_ I have to use?
I have tried using this :
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP|Intent.FLAG_ACTIVITY_SINGLE_TOP);
But this give me the old instance of Activity B, on top of the stack.
Take out the flag Intent.FLAG_ACTIVITY_SINGLE_TOP. From the docs:
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().
I am new to android, I am using the TabActivity. From the TabActivity I am starting the activity from intent. Order of Activity A - B - C - D then from the activity D, How can I create the same new Activity A (destroy the previous A). If i use the FLAG_ACTIVITY_REORDER_TO_FRONT its does not create the activity, instead open the last Activity A, If I use the Clear_top then it destroy the B and C Activity.
Please help to achieve this.
When you are calling Activity B from within activity A, call finish() after creating the new activity B using Intent. This will end the Activity A there. Then again from witin Activity D you can create a new Activity A using intent. Hope this helps.
You might want to consider destroying the previous activity before calling the next activity
so when you are going to call the activity B from A you might want to destroy the activity A using the keyword finish()
and likewise when you move from B to C and C to D and in the D activity destroy the activity of C and call the new activity A that way the A activity will get restarted.
finish(); //finish the current class
Intent intent = new Intent();
intent.setClass(getApplicationcontext(), nextclass.class); //specify the next class
startActivity(intent); //start the next class.
http://developer.android.com/guide/topics/manifest/activity-element.html#lmode
android:launchMode might be the answer you are looking for. From documentation:
Every time there's a new intent for a "standard" activity, a new instance of the class is created to respond to that intent. Each instance handles a single intent.
Means the existing the activity (if exist) will remain in the current stack untouched and new instance will be created at the top of the current stack. So when user back buttons, the user will see your activity A at the bottom of the stack as well.