Develop Reference

Activity launchmode and lifecycle

I have two activities A & B. in A, i am showing a list of titles, and on clicking a title, it will open the detailed article in activity B.
I declare A as singleinstance in Manifest.
But if I declare A as single instance, and when the Activity B is opened and paused, then Activity A is not available on backstack.
I will try to explain by reproducing:
Activity A (launchMode = SingleInstance) with list of titles.
On clicking a title, Activity B opens
On clicking back button/up navigation, Acitiviy B finishes and Activity A resumes.
Again open activity B.
Press home button of device (Activity B goes to background - onPause)
Activity B is available in Recent Apps
Open app from recent apps/launcer - Activity B opens
Clicking back button/up navigation - Act B finishes, but Act A not resumed.
How can I provide better up navigation?

For my idea, you can change lauchmode of Activity A and Activity B from Singleinstance to android:launchMode="singleTop". I work fine for me. It is well said here. Let try.

When you will press the home button the activity B would call onStop() method. For a better understanding you can refer to https://developer.android.com/guide/components/tasks-and-back-stack.html

Always have Activity on bottom of back stack

I have an App with a Navigation Drawer design and some activities (I know working with Fragments would probably be easier here but that wasn't feasible).
When the user clicks a drawer item, the according Activity is started with FLAG_ACTIVITY_REORDER_TO_FRONT. The up button should always take the user back to the start activity A, so when the up button is pressed I also start the A activity with the same flag.
Consider the following (capital letters are the activities, trying to visualize the backstack here):
A
user starts B from the drawer
A -> B
user presses up button, brings A in front
B -> A
user presses back button finishing A going back to B
B
user presses back button again which exits the application, but imho the user should always see the start Activity A again before leaving the app.
How would / did you guys solve this?
EDIT: #Neil, with that is: If I have
A -> B
and from there via drawer go to C I have
A -> B -> C
If the user now presses the Up button and I just close C instead of bringing A to the top, the user will be back in B which would be wrong because C is (navigationwise) not under B but they are 'siblings'.

Try to make the launchMode of that Activity B to SingleTask in your manifest file like this :
android:lanchMode="singleTask"
Your activity will not be called again.

Android back button and resume activity

I have this issue.
I have an actvity A that starts other activity B (by onclick - button).
In B I have one back button to come back to activity A. I press it.
Now that I'm in A, I press again button to go to B.
If I use android back button (I'm in B) I come back to A first and then to B.
But now, if i press android back button again, I don't go to previus activity of A or it exit from app. I come back to B !!!
How can I prevent this behavior ?

The back button of activity B should not start activity A, but close activity B with finish:
http://developer.android.com/reference/android/app/Activity.html#finish%28%29
Note that it is probably bad user interface design to have a "back" button on the interface. This official Android page says "Don't use labeled back buttons"
http://developer.android.com/design/patterns/pure-android.html

if you wish your custom back button to swap between the acivities A and B, you should simply launch intents, that will do.
I believe your problem is with the android back button. If you do not want go to the previous activity with this action, you can write in the manifest file under the <activity> tags for both A and B activities - android:noHistory="true". Doing this will exit from the app. as the activity stack was storing none of the activities, but such a requirement is quite confusing UI approach.

Killing Activities using Back Button

I'd like to kill all activities when the user hits the back button and returns to my main activity A. My App has the following 3 activities:
A -> Displays users selections before they hit search and creates activity B.
B -> Displays a list of urls's based on the users selection and creates activity C.
C -> Opens a Webview and displays the page selected by the user.
Currently, i don't call finish() after starting activity B so when the user hits the back button in activity C they can return to the list of url's and make another selection if they want.
I'd like to create a new activity A (without the users initial selections) and ensure the existing activities B and C are killed if the user hits the back button in activity B?
Any help would be appreciated.
Thanks
O.

You can return to activity A by overriding the back button handler in activity C and launching activity A with the flag FLAG_ACTIVITY_CLEAR_TOP set, or alternatively (perhaps preferably in your case), you can just set noHistory for your activity B.
You'll have to reset activity A manually in some way in this case though.

Android: How to clear activity stack from widget

Is there a way to clear activity stack from widget?
I have following situation:
From widget user presses button what starts new activity A. Next user move from A to new activity B. After that he presses home button which takes him back to home screen. Now if he presses button again, he will be moved directly to the activity B.
I thought ACTIVITY_FLAG_CLEAR_TOP would help, but it didn't.

Does activity A start activity B? If so you can start it with the FLAG_ACTIVITY_NO_HISTORY flag to specify not to put B in the history stack.