I need to finish all the activities running in an Android application when an exit button is clicked. How can I do that?
What I want:
An option menu on screen with an EXIT option.
When I click the Exit menu, the application should close.
How to make a button for the user to immediately finish all Activities
When the user wishes to exit all open activities, have them press a button which loads the first Activity (passing in an intent to clear out all the other activities) that runs when your app starts. Then inside the one remaining activity (LoginActivity), place some code in onCreate to have it choose to self destruct.
Details:
Create a button and call it "exit", make a buttonlistener for that button, and put the following code in there. What it does is load the activity, makes it the only remaining activity by clearing all activities underneath it.
Intent intent = new Intent(getApplicationContext(), LoginActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.putExtra("EXIT", true);
startActivity(intent);
The above code clears all the activities under LoginActivity. The LoginActivity must be the first activity your app runs. So now we are left with only LoginActivity activated. Now we have to get LoginActivity to check the putExtra parameter, and if it has the value "EXIT" then destroy itself as well.
Put the following code inside the LoginActivity's onCreate and onResume, to check the "EXIT" parameter and finish when it is seen:
if (getIntent().getBooleanExtra("EXIT", false)) {
finish();
}
Why is this so hard, why isn't there just an exitAllActivites() function?
Android OS Developers make this hard because they don't want you to give the user an Exit button. They want the user never to care if their App is running or not. If they want it, they run it, if they don't want it, they stop using it. There are benefits to this model, because then an app can be destroyed to make room for a phone call and heavy map-usage, and then they re-run your app, they pick up right where they left off, rather than having to restart from scratch.
So if you use this code, try to cooperate with the Android Developers vision for Android and make it so that the App can be destroyed/recreated at any point, and the user always picks up where they left off. Requiring a user to 'exit' is a hassle.
use StartActivityForResult function for starting a new Activity and when user presses EXIT button, send a unique value as a resultcode. Check for this resultcode in onActivityForResult func and if you find the same unique code then finish the activity.
I don't understand the people who say that this should not be done. Closing an activity can be done quite easily using the built in method to do so.
There is no place in the official documentation that says this should not be done.
For those who think it should not be done for any purpose, maybe you can't think of a reason to do so. There are plenty of legitimate reasons to do this. And since it is a method built in to the Android code.. Google has also decided that you might need to depending on your use. Not all of us only create consumer applications for Android.
So to accomplish this task..shutting down all of the activities in your stack
public void quitApp(){
this.finishAffinity();
}
I created a kiosk app that was run as the default launcher. So I needed a way to exit the app to get to settings or other apps on the device. So in an admin Activity, I placed a pin number pad.. after the user inputs the correct pin, the app needed to exit to the original launcher. I used above code.
You should not implement an Exit button in an Android application.
Read http://groups.google.com/group/android-developers/browse_thread/thread/1bf0f7a4a9c62edd/a0a4aedf21ae5f76?pli=1
Cheers
How to close all activities in Android:
Why are the Android OS devs telling me not to create an Exit button?
If you give developers a hammer, they will use it, and everything becomes a nail, so don't give them a hammer. This is why there is no one-liner to exit all activities.
Why is an Exit button so bad?
You may be frustrated wondering why killing all activities in Android is so difficult. It's hard to do because you've got to bite the bullet and understand how you created the stack, and what it looks like. In what order should the Activities be destroyed? What if the user gets a phone call and needs to nuke your app ASAP? You NEED to have a plan for unwinding. It can't rely on the Activity Manager to babysit your app. If you want to kill your app, the OS devs are twisting your arm to create a unwinding plan because they don't want your application to have any errors when the Activity Manager nukes it.
This self destruct mechanism I go on to describe cooperates with the Activity Manager and causes a cascade effect that causes all activities to finish themselves no matter how they are organized.
To add this cascading self destruct to your app, do these three things:
If you are newbie to android and have never done this before, I suggest you create a brand new bare bones android project to test this out and get a feel for how it behaves. Only when you get the "aha" moment of understanding why this works, then can you extract the usefulness of the code below to delight the user.
Put this override method inside each one of your activities:
#Override
public void onActivityResult(int requestCode, int resultCode, Intent data)
{
//onActivityResult is called when a launched activity exits, giving
//you the requestCode, 1234, that you started it with. The resultCode
//it returned, 900, and any additional Intent data from it. The
//resultCode will be RESULT_CANCELED if the activity explicitly
//returned that, didn't return any result, or crashed during its
//operation.
switch(resultCode)
{
case 900: //Make 900 a final global variable if you want.
//900 means CLOSE_ALL_ACTIVITIES to me. It is
//a signal that the self destruct button has
//been initiated and all activities should end.
setResult(900); //setResult sets the resultCode that will be passed
//to onActivityResult in the activity that called
//this activity. this will immediately tell the
//parent to self destruct even before the next
//command, finish(), is run.
finish(); //Now stop this activity.
break;
}
super.onActivityResult(requestCode, resultCode, data);
}
If you have more than 3 activities, consider having each activity extending a "MyAppActivity" with the above code in there. If you catch yourself copy/pasting the above method into 15 different activities, slap yourself once, and take a class on good Object Oriented Programming. Then read this.
( Details about onActivityResult. ), ( Details about setResult. )
Whenever you have the user start a new activity, you must do it exactly this way:
Intent myIntent = new Intent(getBaseContext(), YourNewActivity.class);
startActivityForResult(myIntent, 1234);
//The 2nd parameter of startActivityForResult is what is sent to
//resultCode in the onActivityResult method. The code `1234`
//doesn't do anything here because it is a flag that is
//ignored in onActivityResult.
More information about startActivityForResult.
If you don't use startActivityForResult, then the self destruct unravelling won't work.
When you want to exit your application, initiate self destruct like this:
setResult(900); //900 is the self destruct code.
finish();
Then the activity stack unwinding plan cascades through the entire app.
you should do this on yourself. read this good blogpost: http://blog.radioactiveyak.com/2010/05/when-to-include-exit-button-in-android.html
Another solution to finish all activities works for me:
Somewhere in my Controller class, there is a method to initiate the shutdown:
/**
* Ask for application shutdown.
*
* <p>
* After the call, the system shall wipe the entire task and activities and
* then call {#link #onTaskWiped()} to finish the cleaning.
* </p>
*/
public void attemptShutdown() {
// wipe the task and its activities.
Application app = getApplication();
Intent intent = new Intent(app, ShutdownActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
app.startActivity(intent);
}
The ShutdownActivity is just performing data cleanup before finishing itself like it was told before.
/**
* This activity is started by {#link Controller#attemptShutdown()} to wipe the
* entire task and activities. It calls {#link Controller#onTaskWiped()} in
* {#link #onCreate(Bundle)} and finish immediately after.
*/
public class ShutdownActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// this is where you release the application data.
Controller.controller.onTaskWiped();
finish();
}
}
And finally the Manifest part. I have set the transparent style to avoid the small flash when the activity appears but it does not seem to work well.
<activity android:label="Exiting..."
android:name=".ShutdownActivity"
android:excludeFromRecents="true"
android:theme="#style/Theme.Transparent" />
Related
I am making an application that will in fact contain two activities.
One will allow the user to log in and if done successfully will launch a web browser (MenuActivity).
The other takes a picture and uploads it to a server (PhotoActivity).
That web browser will have a link that when pressed will load my application in picture taking mode.
The flow is usually something like this:
MenuActivity->web browser->PictureActivity and then the last two steps repeat.
I have done this so far by setting my launcher activity as the MenuActivity and then putting using this code in the OnCreate override:
Intent mine = getIntent();
if (mine.getData() != null && !mine.getData().getPathSegments().isEmpty()) {
//retrieve the data here that I need
Intent i = new Intent(this, typeof(PhotoActivity));
i.PutExtra(//add here the data I received);
StartActivityForResult(i, START_PHOTO_INTENT);
}
after that I override OnActivityResult and send finish() if the requestCode is START_PHOTO_INTENT
This works correctly
my problem is that when I start the PhotoActivity from the web browser, if the user (while this is open) opens the application, then the MenuActivity shows (which it should) but when the user pressed back on it, it goes back to the PhotoActivity instead of exiting.
Is there a way to change this behaviour so that , even if the PhotoActivity is open, if the application is started manually, the PhotoActivity will not remain on the backstack ?
Thanks in advance for any help you can provide
Edit:
After reading the linked article at the solution and the answers to this question I came to the conclusion that in order to do what I want I had to set LaunchMode as singleTask in androidmanifest, and override MenuActivity's OnStop and send finish() after it was executed (if I didn't and the activity was in the backstack then it wouldn't be fired with the intent data when launched from a web page)
thanks for the help all of you
Look at the Handling affinities chapter in Tasks and Back Stack documentation. It is described how to handle this.
please do
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
This will start a new task for your application
We have a requirement to force the user to set up a password the first time he/she starts the app. So we have our main activity with launchMode=singleTask which start a password setting activity using startActivityForResult.
We also want the user to go back to their home if he/she taps back from the password setting page so we put the code to finish the main activity in its onActivityResult if it receives RESULT_CANCELLED. However, if the user taps home and re-enter our app, we want to show the password setting page again. But in this case, it will be destroyed (because main activity's launchMode is singleTask) and also returns RESULT_CANCELLED to our main activity causing it to be finished.
So the problem is from main activity, we cannot distinguish between tapping back and tapping home then re-enter the app.
Is there anyway to fulfill this requirement while still keeping the launchMode as singleTask ?
onBackPressed() for tapping back
Called when the activity has detected the user's press of the back
key. The default implementation simply finishes the current activity,
but you can override this to do whatever you want.
http://developer.android.com/reference/android/app/Activity.html#onBackPressed%28%29
&&
onPause() for home screen
(though it can be due to other things also like your next activity or switching to another application)
http://developer.android.com/reference/android/app/Activity.html#onPause%28%29
Update :
Why Don't you use Sharedpreferences and check if the app is run for the first time and password/rest fields are set rather than using the approach you are using right now .
I had a very similar issue recently.
What I would suggest is that you don't actually finish the app when you get the RESULT_CANCELLED.
Instead do something like:
protected void onActivityResult(int requestCode, int resultCode, Intent intent) {
if (resultCode == Activity.RESULT_CANCELED) {
if (/*TEST IF A USER IS SIGNED IN*/) {
//IF SIGNED IN PROCEED TO MAIN ACTIVITY
}
// OTHERWISE FORCE THEM TO SIGNIN/REGISTER/WHATEVER AGAIN
// WITH ANOTHER CALL TO startActivityForResult
...
This is a back of an envelope approach to your problem, but this pattern has worked for me.
For me, my Authentication/Registration is all done in an Abstarct Class that extends Activity. Each of my activities then extends this class. I Place the Auth/Reg method calls in the onResume() of this Abstarct Class.
When a startActivityForResult is launched in the onResume() method and fails I don't finish() the activity but just let the app proceed and let the class handle which Reg/Auth form to present. Which it will do by checking various flags to determine what action it is meant to be performing.
The added benefit of this approach is that each and every Activity that might extend this abstract class gets the added benefit of a security check each time it is used.
My application starts with a welcome screen Activity, but that screen has an option to skip that screen altogether in future launches.
What's the proper Android way to do this? Initially, I just automatically detected the skipWelcome preference and switched to the 2nd activity from Welcome. But this had the effect of allowing the user to hit the back button to the welcome screen we promised never to show again.
Right now, in the Welcome activity, I read the preference and call finish() on the current activity:
SharedPreferences preferences = getPreferences(MODE_PRIVATE);
boolean skipWelcome = preferences.getBoolean("skipWelcome", false);
if (skipWelcome) {
this.finish();
}
And then I implement onDestroy to move on to the next Activity:
#Override
public void onDestroy() {
super.onDestroy();
startActivity(new Intent(Welcome.this, StartFoo.class));
}
But this makes for some weird visual transitions. I'm starting to think that I need a base Activity that pops open Welcome only if proper, and then goes to StartFoo.
I can't comment on Mayra's answer or I would (not enough rep), but that's the correct approach.
Hidden in the Android documentation is this important phrase for Activity.startActivityForResult(),
"As a special case, if you call
startActivityForResult() with a
requestCode >= 0 during the initial
onCreate(Bundle
savedInstanceState)/onResume() of your
activity, then your window will not be
displayed until a result is returned
back from the started activity. This
is to avoid visible flickering when
redirecting to another activity."
Another important note is that this call does not block and execution continues, so you need to stop execution of the onCreate by returning
if (skipWelcome) {
// Create intent
// Launch intent with startActivityForResult()
return;
}
The final piece is to call finish immediately in the welcome activity's onActivityResult as Mayra says.
There are a few solutions to this.
Did you try just launching the activity and finishing? I vauguely remember that working, but I could be wrong.
More correctly, in if(skipWelcome) you can start the new activity for result, then when onActivityResult is called, immidiately finish the welcome activity.
Or, you can have your launcher activity not have a view (don't set content), and launch either the welcome activity or StartFoo.
I am developing an app with numerous Activities. I would like to create a persistent notification that (more or less) says, "AppName - Return to AppName" that will be present whenever my background services are running. Creating and disposing of the notification was no problem.
Now, the user could be on any of several screens/Activities, leave the application, then want to re-enter the app via the notification. The problem is, the notification must have an intent, which launches a predetermined Activity. I want the notification to re-enter the app in whatever Activity is at the top of the history stack.
My first attempt at an ugly workaround was to make an activity (let's call it "returnFromNotify") whose only job was to "finish" itself in it's "onCreate". The notification would open "returnFromNotify" in the scope of the applications history, which would then immediately remove itself, sending the user back to the previous history state in the application stack. This seems to work... unless the user has used "back" to completely back out of the app. Then, when they hit the notification, "returnFromNotify" loads, then finishes, sending them back out to the home screen (as there are no activities in the history stack for the app).
I considered trying to detect if there was anything in the history stack before "returnFromNotify", and if not, fire up my main Activity. I can't seem to find a way to do this, either.
Any input or suggestions for a Java/Android novice? FYI, My primary history is with script-based languages.
I like your original idea of creating a "returnFromNotify" activity better than your proposed workaround, as it is possible to detect if the ResumeActivity is at the bottom of the stack (and therefore the only activity in the stack).
Here's how you can do it:
Add your ResumeActivity to the manifest and specify the noHistory attribute:
<activity android:name=".ResumeActivity" android:noHistory="true" />
Specifying noHistory will make sure this Activity won't stay in the stack as soon as it finishes. This way you know that only a currently running instance of the ResumeActivity will show up in the stack.
In order to check the application stack, you'll also have to ask for the GET_TASKS permission:
<uses-permission android:name="android.permission.GET_TASKS" />
Now you can use ActivityManager::getRunningTasks() to determine if ResumeActivity is the only activity in the stack:
public class ResumeActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if(isOnlyActivityInStack()) { //check the application stack
//This activity is the only activity in the application stack, so we need to launch the main activity
Intent main = new Intent(this, MainActivity.class);
main.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(main);
} else {
//Return the user to the last activity they had open
this.finish();
}
}
/**
* Checks the currently running tasks. If this activity is the base activity, we know it's the only activity in the stack
*
* #return boolean This activity is the only activity in the stack?
**/
private boolean isOnlyActivityInStack() {
ActivityManager manager = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);
boolean onlyActivityInStack = false;
for(RunningTaskInfo tasks : manager.getRunningTasks(Integer.MAX_VALUE)) {
if(tasks.baseActivity.getPackageName().equals(this.getPackageName())) { //find this package's application stack
if(tasks.baseActivity.getClassName().equals(this.getClass().getName())) {
//If the ResumeActivity is the base activity, we know that it is the only activity in the stack
onlyActivityInStack = true;
break;
}
}
}
return onlyActivityInStack;
}
}
I know you asked this question over 2 years ago, but I'm providing this answer in case anyone else runs in to this particular situation (as I did). I think you were on the right track with the solution you were originally working towards.
Okay, I believe that I have found a satisfactory work-around for my specific case. I've added a static integer to my "mainActivity", and each time it's "onCreate" is fired, it increments the integer. Each time it's "onDestroy" is fired, it decrements.
In my "returnFromNotify", I look at the static integer to see if it is greater than 0. If so, I assume there is an active "mainActivity", and that running "finish" inside "returnFromNotify" will return there. Otherwise, it assumes the users has "backed" out, finishes itself, then uses "startActivity" to fire up a new instance of "mainActivity".
This is not a universal solution, but for my purposes, I think it will suffice. I am still open to other answers, and if someone can punch a hole in my logic, please do so - constructive criticism is welcome. Thanks.
I guess there is no easy way to do this but instead of adding a counter in the mainActivity I would extend Application:
Base class for those who need to
maintain global application state. You
can provide your own implementation by
specifying its name in your
AndroidManifest.xml's
tag, which will cause that class to be
instantiated for you when the process
for your application/package is
created.
I would mantein the logic there and have a method like:
public Intent getIntentForLastActivityShown();
to be called when the notification item is clicked.
My first approach would be to use SharedPreferences and store a key value pair called something like lastDisplayedActivity. Then in each Activity's onResume (and possibly `onCreate') you would have a line like this:
sharedPreferences.edit().putInteger("lastDisplayedActivity", ReturnFromNotify.THIS_ACTIVITY_NAME);
In other words, you store an application-wide variable indicating which activity was last displayed. Then you just grab this variable from SharedPreferences and launch the corresponding activity.
I usually use activity named "Launcher" that checks state of my application model and starts activities (or does other things) depending on model rules. I put Model object in my Application class. Model can use Preferences to store its state. I do it to avoid static fields in activities.
This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Quitting an application - is that frowned upon?
I want to offer the user an option to exit the application as I need to delete some sensitive data, which is stored in the SharedPreferences as long as the application needs it.
As soon as the user wants to exit, the password in the SharedPreferences should be wiped and of course all activities of the application should be closed (it makes no sense to run them without the known password - they would crash).
How can I do that?
System.exit(0) and finish() only exit the current activity - useless. I know there is a taskmanager app. How is that one doing it? It's able to kill the whole application...
When you use the finish() method, it does not close the process completely , it is STILL working in background.
Please use this code in Main Activity (Please don't use in every activities or sub Activities):
#Override
public void onBackPressed() {
android.os.Process.killProcess(android.os.Process.myPid());
// This above line close correctly
}
You are correct: calling finish() will only exit the current activity, not the entire application. however, there is a workaround for this:
Every time you start an Activity, start it using startActivityForResult(...). When you want to close the entire app, you can do something like this:
setResult(RESULT_CLOSE_ALL);
finish();
Then define every activity's onActivityResult(...) callback so when an activity returns with the RESULT_CLOSE_ALL value, it also calls finish():
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch(resultCode)
{
case RESULT_CLOSE_ALL:
setResult(RESULT_CLOSE_ALL);
finish();
}
super.onActivityResult(requestCode, resultCode, data);
}
This will cause a cascade effect closing all activities.
Also, I support CommonsWare in his suggestion: store the password in a variable so that it will be destroyed when the application is closed.
When the user wishes to exit all open activities, they should press a button which loads the first Activity that runs when your app starts, in my case "LoginActivity".
Intent intent = new Intent(getApplicationContext(), LoginActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.putExtra("EXIT", true);
startActivity(intent);
The above code clears all the activities except for LoginActivity. LoginActivity is the first activity that is brought up when the user runs the program. Then put this code inside the LoginActivity's onCreate, to signal when it should self destruct when the 'Exit' message is passed.
if (getIntent().getBooleanExtra("EXIT", false)) {
finish();
}
The answer you get to this question from the Android platform is: "Don't make an exit button. Finish activities the user no longer wants, and the Activity manager will clean them up as it sees fit."
which is stored in the
SharesPreferences as long as the
application needs it.
Why?
As soon as the user wants to exit, the
password in the SharedPreferences
should be wiped and of course all
activities of the application should
be closed (it makes no sense to run
them without the known password - they
would crash).
Even better: don't put the password in SharedPreferences. Hold onto it in a static data member. The data will naturally go away when all activities in the app are exited (e.g., BACK button) or otherwise destroyed (e.g., kicked out of RAM to make room for other activities sometime after the user pressed HOME).
If you want some sort of proactive "flush password", just set the static data member to null, and have your activities check that member and take appropriate action when it is null.
Using onBackPressed() method:
#Override
public void onBackPressed() {
android.os.Process.killProcess(android.os.Process.myPid());
}
or use the finish() method, I have something like
//Password Error, I call function
Quit();
protected void Quit() {
super.finish();
}
With super.finish() you close the super class's activity.
My understanding of the Android application framework is that this is specifically not permitted. An application is closed automatically when it contains no more current activities. Trying to create a "kill" button is apparently contrary to the intended design of the application system.
To get the sort of effect you want, you could initiate your various activities with startActivityForResult(), and have the exit button send back a result which tells the parent activity to finish(). That activity could then send the same result as part of its onDestroy(), which would cascade back to the main activity and result in no running activities, which should cause the app to close.