Develop Reference

Destroy/ finish previous activities from the current fragment in android

I have been developing this application for quite a while now and came up with this bug in the app. Initially when the application loads for the first time, it starts from the home activity. Then the user interaction will navigate application to activity1 which uses fragment1. The fragment1 has a button. If the user clicks on that button,the activity1 calls finish() and loads activity2 by calling startActivity().Also when the user clicks on the hardware back button from the fargment1, the application returns to the Home activity.
So the real issue here is that, when I am at activity2 and finish() the activity the application will show the Home activity. But i want to completely close the application on pressing back from the activity2.
The following is the code which starts the activity2 form the fragment1:
Intent intent = new Intent(context, Activity2.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
((Activity)context).finish();
I get that the Home activity has never been finish()-ed.
So how do I destroy the activity1 and home activity on navigating to the activity2, and make the activity2 only remaining activity in the application?
Thanks in advance.

Ok so this is what i did (according to #seema):
in the home activity i registered a broadcastreciever in OnCreate() method of the activity.
IntentFilter filter = new IntentFilter();
filter.addAction("com.example.CUSTOM_INTENT");
registerReceiver(receiver, filter);
BroadcastReceiver receiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
Log.d("==>","Broadcast Recieved.");
finish();
}
};
public void finish() {
super.finish();
};
then in the activity2 i send out the broadcast
Intent local = new Intent();
local.setAction("com.example.CUSTOM_INTENT");
sendBroadcast(local);
This worked out as I required it to be.
Thus any activity can be destroyed from any other activity.

First approach: use start activity for result instead of start activity and finish it in onActivityResult.
Second apparoach: Register a local broadcast in each required activity and in its receiver, finish it. From activtity2 send this broadcast. This will finiah all those activities in stack having that broadcast registered. I have used this approach for Logout implementation in many apps and it works well.

Start Activity and Bring it to Front

I have a service that once it completes a task it launches an intent to start an activity from my application. Like this:
Intent i = new Intent(MyService.this, MyActivityToBringToFront.class);
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
//i.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
//i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
//i.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP);
startActivity(i);
This service can be running even after my application has been closed. When this is the case and my application is closed I need it to bring the activity to the front of whatever the user is currently doing. So if the user is in a different app I need my activity to pop up in front. Is this possible. None of the flags had any effect. Basically I need it to be like the system phone application. When you get a phone call it always brings the phone to the front. How can I do this? Thanks!

First of all you need to keep context in memory to make intent's.
Secondary you need a mechanism that can re-obtaining your context every 24 hours because usually context stay alive in 24 hours.
After.
Launching Activity from service :
Intent dialogIntent = new Intent(getBaseContext(), myActivity.class);
dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
getApplication().startActivity(dialogIntent);
source : https://stackoverflow.com/a/3607934/2956344
To push activity on top add
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_SINGLE_TOP);

Intent i = new Intent();
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
i.setAction("android.intent.action.VIEW");
i.setComponent(ComponentName.unflattenFromString("com.example.package/com.example.package.activityName"));
startActivity(i);

Intent i = new Intent(MyService.this, MyActivityToBringToFront.class);
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK|Intent.FLAG_ACTIVITY_CLEAR_TOP);
context.startActivity( i);
And API reference is
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.
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().
This launch mode can also be used to good effect in conjunction with
FLAG_ACTIVITY_NEW_TASK: if used to start the root activity of a task,
it will bring any currently running instance of that task to the
foreground, and then clear it to its root state. This is especially
useful, for example, when launching an activity from the notification
manager.

launching an activity from a service isn't always a good idea. You may want to use notification for that. If the user clicks on the notification, thats the time you show the Activity.

How do I force an activity to use the intent extras I pass it?

I have a stack of activities, and use the following code to bring the main activity to the 'active' state:
Intent i = getBaseContext().getPackageManager()
.getLaunchIntentForPackage(getBaseContext().getPackageName());
i.putExtra("clearCache", true);
i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
The problem is that when I try to retrieve the clearCache extra, a call to getIntent().getExtras() returns null.
My understanding is that because the activity that I'm launching was already on the stack, and because I set the Intent.FLAG_ACTIVITY_CLEAR_TOP flag, the Intent that gets returned will be the original intent.
How do I access the calling intent in the activity I'm launching?

In the google documentation on FLAG_ACTIVITY_CLEAR_TOP, you should be getting the new intent each time:
"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."
...
"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()."
For more details take a look here:
http://developer.android.com/reference/android/content/Intent.html#FLAG_ACTIVITY_CLEAR_TOP
Hope that helps!

You just change your code by passing the particular Activity name and keep the rest of code as it is,
Intent i = new Intent(MapActivity.this, MainActivity.class);
i.putExtra("clearCache", true);
i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);

How do I bring my activity to the front using broadcastReceiver onReceive()?

All of this has to do with my own app.
I have two cases. First, my activity is on top, and everything works fine. My service broadcasts info and my activity updates its GUI.
My problem is that I don't know how to bring my activity to the front if its not already there. Ideally, all the activities in front of it would be closed and this one be brought to the front. How do i do this?
broadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
//what code do I put here to bring this activity to the front and close all other activities on top of it?
}
};
Here is how I solved the problem with the help of the post bellow.
Intent i = new Intent();
i.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP | Intent.FLAG_ACTIVITY_CLEAR_TOP);
i.setClass(MyClass.this, MyClass.class);
startActivity(i);

First of all there isn't a direct command to bring an activity to front such as myActivity.bringToFront. Instead you will have to let android do it for you through the intents mechanism.
So if you want to bring an activity to front you will have to call startActivity and pass an intent with the correct flags. For example the flag FLAG_ACTIVITY_CLEAR_TOP will do your job. However there is a catch, you cannot set this flag if you use startActivity from within a broadcast receiver or a service. So in your case I think that you should use the flag FLAG_ACTIVITY_NEW_TASK.
Here is an example:
Intent i = null;
i = new Intent(context, My_activity.class).setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(i);
Hope this helps...

clear Activity Stack when user Logs in

There are a lot of topics on this post. But i couldn't find a solution to my problem.
Let me describe my activity stack first.
SplashScreen->A->Login->Home.
What i would like to achieve is , when i click on back button after logging in to Home, i should come out of the application and go to Home if i use my application again. For this i am assuming i should clear the activity stack before Home, after i login. I would also like to preserve the activity stack if the user hasn't logged in yet.
I want this to work on or after 2.1
What i have tried already.
using finish() in Login Activity , before calling startActivity on Home. This will redirect me to A , if i use back button on Home.
All variations of FLAG_ACTIVITY_NEW_TASK and FLAG_ACTIVITY_CLEAR_TOP . Nothing worked, when i use back button, i am redirected to login screen.
Any suggestions or simple solution to achieve this?

using finish() in Login Activity , before calling startActivity on Home. This will redirect me to A , if i use back button on Home.
ok so use finish on all the activities that you want them to be popped before calling startActivity
go to Home if i use my application again
Simply save your login parameters in SharedPreference and from A startActivity Home directly if login successful.

You can also try to make use of BroadcastReceiver aswell if you want to try that route.
In your "SplashScreen" and "A" activities, in the onCreate method you can create and register and IntentFilter and a BroadcastReceiver like so:
Assuming you have a global variable called broadcastReceiver
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction("ACTION_LOGIN");
this.broadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
finish();
}
};
registerReceiver(broadcastReceiver, intentFilter);
Also don't forget to unregister your receiver in the onDestroy method (this is to prevent memory leaks in the program):
#Override
protected void onDestroy() {
unregisterReceiver(this.broadcastReceiver);
super.onDestroy();
}
Now in your "Login" activity, once the user has successfully logged in, you can broadcast a message to all the registered receivers, which will finish those activites in the back stack:
Intent broadcastIntent = new Intent();
broadcastIntent.setAction("ACTION_LOGIN");
sendBroadcast(broadcastIntent);
Your SplashScreen and A activities will now be finished.