Develop Reference

How to resume an application from another application?

Actually, I know how to launch an application from another application.
The problem is that the application always restarts instead of resuming when I launch it from another application after launching it from home screen. (I mean the application is running first by pressing the shortcut from home screen)
For example,
There are two applications : A, B
Launch two applications from home screen first.
Launch A application again from B application.
A application restarts instead of resuming.
How could I resume it?
Now I am doing it as below.
Intent intent = getPackageManager().getLaunchIntentForPackage(PACKAGE);
intent.setAction(ACTION);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK|Intent.FLAG_ACTIVITY_SINGLE_TOP);
startActivity(intent);
ACTION is custom action.
Please help.

You can check for the Intent.CATEGORY_LAUNCHER category and Intent.ACTION_MAIN action in the intent that starts the initial Activity.
If those two flags are present and the Activity is not at the root of the task (ie.. app was already running), then I call finish() on the initial Activity. That exact solution may not work for you, but something similar should.
Here is what I do in onCreate() of the initial/launch Activity:
if (!isTaskRoot()
&& getIntent().hasCategory(Intent.CATEGORY_LAUNCHER)
&& getIntent().getAction() != null
&& getIntent().getAction().equals(Intent.ACTION_MAIN)) {
finish();
return;
}

You need to set the ACTIVITY_REORDER_TO_FRONT flag on your Intent when you call Context.startActivity().

Show *only* a toast (no UI) after sharing text into an app?

I'm a starting Android developer and would like to know how to achieve this:
1# User is using e.g. Chrome
2# User wants to share the page (meaning: the URL, which is text) into an app
3# User chooses the app from the share menu
4# The app shows only a small notification on top of Chrome (current foreground app, which is the sender of the intent)
So the app would receive the intent from Chrome and do something with it, but wouldn't change the foreground app. It would stay in the background and show only a very small notification to the user that the sharing of the URL into this app actually succeeded. Toast or something like that.
This is basically the way for instance Pocket handles sharing into it.
How can I achieve this? IntentService? I cannot seem to find the correct answer to this. Theme.NoDisplay, Intent, IntentService – I cannot figure out the correct way since I'm not too familiar with Android yet.
Thank you a lot in advance!

Use the NoDisplay theme (update activity declaration in manifest) in the activity that does your sharing work as follows:
android:theme="#android:style/Theme.NoDisplay"
This will prevent the activity from being displayed.
Then once the activity starts, do your sharing task, display the Toast and call finish()

finish your activity onResume(). It will not shows any of Your Activity.
You can do like this:
protected void onResume() {
super.onResume();
finish();
}

ANDROID: open an URL in external browser, while continuing the application

In the starting activity of my app I show a dialog to user and ask if he wants to see some contents in my website or not.
If he clicks No, the dialog disappears and I call continueActivity() to do some process and go from current activity to MainActivity.
If he click yes, I want to open the webpage in the external browser and again I call continueActivity() to do some process and go from current activity to MainActivity.
The problem is in positive state. This is my code in positive state:
Intent browserIntent = new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.aaa.ir"));
startActivity(browserIntent);
continueActivity();
Because of calling continueActivity(), the external browser can't open and if I don't call continueActivity(), the URL opens in the external browser and the app sticks in the current activity.
So how could I open the URL and at the same time, continue the process and go to other activities.

I usually use
startActivityForResult(browserIntent, BROWSER_REQUEST);
and override onActivityResult(int reqCode, int resultStat, Intent intent)
if(reqCode == BROWSER_REQUEST) {
continueActivity();
}

Once you call startActivity, your current Activity will follow through the exit of the Activity lifecycle. This is unavoidable.
If you have processing you want to continue in the meantime, you should consider a Service. If you want the App to return to its current state, you need to store relevant data and load your Activity to its previous state (or next intended state).

in both ways ContinueActivity is opening. i don't know you architecture. You could just add to intent some extra like
intent.putBoolean("openExternalLink", dialogResultHere);
Then in continueActivity you will got this intent like
getIntent().getBoolean("openExternalLink")
also dont forget to delete this option, otherwise you will open browser each time after Activity recreation (screen rotation, minimize, etc.)
getIntent().removeBoolean("openExternalLink");
P.S. signatures of methods could be littlebit different, but general idea is here

Create new intent in background

I am looking for a way to launch another app from within my app but so that the focus is not changed from my app to the app launched.
I.e currently I have the new app launched via a intent, however when this is carried out the new app is launched and becomes the app in view, I need it to be kept in the background with my app still in view.
The reason for this?
I am developing an application for internal use that will act like a lock-screen to the device so although things must happen in the background the 'lock-screen' must always be on top.
I have done some research into intents and launching other apps but can not find anything about what I need.
Hope you can help thank you!
Currently the terminal is called like this:
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.setComponent(new ComponentName("jackpal.androidterm", "jackpal.androidterm.RemoteInterface"));
intent.setAction("jackpal.androidterm.RUN_SCRIPT");
intent.putExtra("jackpal.androidterm.iInitialCommand", cmdString);
The reason it needs to be running in the background is so that the app can run commands in terminal without the user having access, but then they 'unlock' the screen they need to then be able to view the terminal and what commands are being run etc

You can not startActivity in Background.Instead start the activity and minimise the activity(in your case this activity is of different application) using moveTaskToBack(true);
In your case, put a condition based on your intent and its params and use moveTaskToBack(true); so that activity will be minimised only when your application launches.

This won't be possible, you will have to start a background Service that does the actual work and only launch the Activity you want to navigate to once your foreground Activity is finished. Depending on your architecture, you can store the Activity to call when your foreground Activity is finished and change it from the service. That way you will have your desire behaviour without having to actually call the Activity.

In addition to the answer from #Meher, in the intent for your current starting activity, you can add the flag FLAG_FROM_BACKGROUND.
With this you get rid of the "blinking" effect (the one where your activity shows for one fraction of second while it discovers wether to go to background)

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);