Android SingleTask not working - android

I have a multiple activities in my application. Two of them are a LoginActivity and the second one is a SettingsActivity. The user logs into the Settings activity and logs out of the application from the SettingsActivity. The flow of the application is LoginActivity -> HomeActivity -> SettingsActivity . The user calls the logout from the application in the Settings Activity. I call finish on the Settings activity and create an intent to the LoginActivity. This works fine, but when i press the back on the loginactivity the home activity appears. I want that once the LoginActivity appears the back button should take the application out of the application. How can i do this ?

The answer lies in FLAG_ACTIVITY_CLEAR_TOP.
All you need to do is set the flag to your intent like shown below
Intent i = new Intent(this, LoginActivity.class);
i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
finish();
That should pretty much do what you want it to do.

I believe this is what you are looking for:
How to clear the Android Stack of activities?
I wouldnt get too hung up on the fact that it doesnt actually finish() your LoginActivity - this is actually a pretty normal pattern to follow.

I had to use .FLAG_ACTIVITY_CLEAR_TASK for this to work . I read this is supported after API version 11, will these do for all previous versions. Secondly how can i use these from the Manifest file and not the java code ?
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK|Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TOP);

Related

Best way to handle activity state

I'm making an app that shows another activity when I correctly login however in the home screen when I pressed back and then returned to the app the login activity showed.
I was able to avoid this overriding the onBackPressed this way:
public void onBackPressed()
moveTaskToBack(true);
}
Is this the best way to do it? Is there a more proper way to keep the state of the application when I exit it?
In your login activity after starting intent call finish()
finish destroy your activity and avoid to run it again automatically.
Your issue is that you kept LoginActivity in stack. so when you press back it will kill MainActivity(after login) and since LoginAcitivity still there. it will be shown again. best is to kill LoginAcitivty after starting new activity.
call this in LoginActivity:
Intent intent = new Intent(context, MainActivity.class);
startActivity(intent);
finish();
As you question I understand, you want to clear the entire history stack and start a new activity. For this, in API level 11 a new Intent Flag was added which is: Intent.FLAG_ACTIVITY_CLEAR_TASK
Just to clarify, use this:
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
For API <=10 now one can use IntentCompat class for the same. One can use IntentCompat.FLAG_ACTIVITY_CLEAR_TASK flag to clear task. So you can support pre API level 11 as well.

How to start a new Intent that will clear all other activities?

To lay it out as simply as possible. My user enters the app through Activity A. They "login" and then Activity B is started, and Activity A is finished using finish() so that the users can't get back to the login screen by pressing back from Activity B. Now in Activity B, they move to Activity C, and in activity C, I want them to start a new intent that will start activity A, but "kill"/"finish" all other activities. The only way I can think of doing this is using an Intent Flag. so far I've come up with:
Intent intent = new Intent(getActivity(), ActivityA.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET|Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED);
startActivity(intent);
But the code above doesn't work. I still see that my app had a savedInstanceState in Activity B. Hence something like CLEAR_TASK won't work for me case.
EDIT: Also, is there an easy way to tell have many "tasks" your app has opened currently?
Note: There seems to be other flags that may help, but they were added in API 11, and I need to support API 10.
Flag combos I've tried:
Doesn't work
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET|Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED);
Doesn't work
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TOP);
You need to use IntentCompat. like
import android.support.v4.content.IntentCompat;
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK |IntentCompat.FLAG_ACTIVITY_CLEAR_TASK);
Check whether the below answer helps you:
http://www.hrupin.com/2011/10/how-to-finish-all-activities-in-your-android-application-through-simple-call

remove activity from stack

I am developing an application in android. I am new in android.
In my application I have a category selection activity from that user have to check a check-box, based on that he will get view on another screen. I have a menu button in 3rd screen in that I have a button for selecting category, when I click on that button its also works fine but when I click back button it will redirect me 2 times at same activity... How to remove this problem? I have used finish() method but its also creates problem its get's me out from the application directly...
I want redirect to selection activity and it should not show me 2 times when I click back button ....
Is there any way please redirect me thank you.
a call to finish() should work so you schould check your code for multiple calling the wrong method or something like this.
Intent intent = new Intent(activity, activityClass.class);
activity.startActivity(intent);
finish();
you should also take a look at the Intent flags:
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.addFlags(Intent.FLAG_ACTIVITY_NO_HISTORY);
intent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
Your question isn't clear enough for me to know if this will solve your problem, but if you include the following attributes on your Activity in AndroidManifest.xml, the so-attributed Activity will never appear in your history list.
android:excludeFromRecents="true"
android:noHistory="true"
As for removing something from the history, I'm not sure how to do that, but I'm interested in the answer!
You should call finish before you call Intent and go to next activity. so the current task is finished and will not be saved in stack and then you intent activity will come on top of stack. If you directly want to go to Selection activity, override onBackPressed() and intent to the activity you want to go to.
There are different flags that you can use to control how your activity interacts with the activity history stack. Two that might be of interest to you are FLAG_ACTIVITY_CLEAR_TOP and FLAG_ACTIVITY_NO_HISTORY.

How i can close/exit button on my app?

i have a button to close my app with this code:
finish();
the problem is that this button doesn't exit of my app... it simply closes the current intent ant returns to the previous intent (window) of my app....
how i can do a real exit/close button?
i tryed with this:
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
but it doesn't works, because when i turn back into my app, the app comes in the last opened window, and not in the first window of the app, how i can do that? i need that when i re-open my app it starts on the first window of my app
If you really want your app to die. You could initiate each intent with startActivityForResult(). then before each finish() set the result to send back. in each parent activity you can override onActivityResult() to test whether the result received means the application needs to end. if so you can call another set result and finish(). repeat this in all activities and you will find that your application terminates entirely.
Incidentally I'm writing this from memory. function names may not be exact.
Hope that helps.
p.s. re-read your requirements. you can always stop the finish loop at your first activity.
I would do it this way:
I would define my initial activity (i.e. MainMenu) with a Launch Mode of singleTop
I would then invoke my MainMenu from the activity that is going to close the application.
startActivity(new Intent(this, MainMenu.class).addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP).putExtra("closeProgram", true);
Then override the onNewIntent in the MainMenu activity; check for the extra boolean of "closeProgram", if the value is true, then do a finish();
Haven't tried it but I think it should work.
I recommend you read this: http://blog.radioactiveyak.com/2010/05/when-to-include-exit-button-in-android.html
Chances are, you don't want an exit button. Perhaps a logout button, but that's it.
finish() closes activity (this is what you call intent, but it's not correct), not application. Application can not be finished at all (only forcefully killed like task killers do). You should design your activity stack in such a way that it will suit your needs. May be you should look at stack rearrangement examples in ApiDemos.
you can try this: System.exit(0);

Launching an activity at its current state

I am trying to make a task switcher and I succeeded in it. My only problem is that when I launch activities, they are relaunched as they were new activities ( for instance, I am writing an email, I press home and go into my activity,launch email, and then the app launch the email bout goes back to the inbox and the email is lost) So that's not true multitasking.
Here are my steps:
1) getting all the running apps:
List<ActivityManager.RunningTaskInfo> allTasks = activityManager.getRunningTasks(30);
2) getting the intent:
for (ActivityManager.RunningTaskInfo aTask : allTasks) {
Intent i = new Intent(Intent.ACTION_MAIN);
i.setComponent(aTask.baseActivity);
(...)
3) Launching the application when clicking on the button:
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK| Intent.FLAG_ACTIVITY_RESET_TASK_IF_NEEDED).addCategory(Intent.CATEGORY_LAUNCHER);
monthis.startActivity(intent);
`
What is wrong with this code? Should I do something different to get it?
Thank a lot for any answer.
When creating the Intents you should not use Intent.FLAG_ACTIVITY_NEW_TASK, you should use FLAG_ACTIVITY_REORDER_TO_FRONT.
Sorry if I made mistakes in my explanation, I am quite a "noob" and just tell here my experience to improve the result of people searching for the same answer than me.
In fact, I had to Use intent.setFlag(FLAG_ACTIVITY_NEW_TASK | FLAG_ACTIVITY_REORDER_TO_FRONT) for the best result. Replacing was not the best Idea.
Not using FLAG_ACTIVITY_NEW_TASK make the email application launch when I wanted to launch my own application. Because email was "linked" with the same task than my Application.
But Lucas, I keep your answer as the best.
I think I found the answer. Let me tell what i have done in simple words,
Suppose i am having two activities activity1 and activity2 and i am navigating from activity1 to activity2(i have done some works in activity2) and again back to activity 1 by clicking on a button in activity1. Now at this stage I wanted to go back to activity2 and i want to see my activity2 in the same condition when I last left activity2.
For the above scenario what i have done is that in the manifest i made some changes like this:
<activity android:name=".activity2"
android:alwaysRetainTaskState="True"
android:launchMode="singleInstance">
</activity>
And in the activity1 on the button click event i have done like this:
Intent intent=new Intent();
intent.setFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
intent.setClassName(this,"com.mainscreen.activity2");
startActivity(intent);
And in activity2 on button click event i have done like this:
Intent intent=new Intent();
intent.setClassName(this,"com.mainscreen.activity1");
startActivity(intent);
Now what will happen is that whatever the changes we have made in the activity2 will not be lost, and we can view activity2 in the same state as we left previously.
I believe this is the answer and this works fine for me. Correct me if i am wrong.

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