Develop Reference

How to launch another app or bring it back to foreground like Android launcher?

I am developing two apps that will be installed on the same device. My customer wants a shortcut button on each to jump to the other app in its current state. This action would duplicate the behavior of pressing HOME then pressing the other app's launcher icon. If the app has not been started, it would start it. If the app has already been started, then the current activity is resumed. Each app has many activities, so the current activity at the top of each app's task stack would be unknown at run-time. I have searched all over and have not found this problem answer sufficiently. I have tried variations on this code without success:
Intent intent = getPackageManager().getLaunchIntentForPackage("com.example");
intent.setAction(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_LAUNCHER);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
I am at a loss, any help is appreciated.

I figured out my problem. Here is what works:
Intent intent = new Intent();
intent.setComponent(new ComponentName("com.example", "com.example.MyActivity"));
intent.setAction(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_LAUNCHER);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);

Failed to go back to home screen from Android apps

I have a button in my app named "Go Home" to redirect the user to the home screen. It is working fine without the very first launch. The process of first launch is noted below:
After uploading the APK into SVN I am downloading using the web browser. Then go back to the download folder and installing the app. When install finishes I click on Open. Then In my app I click on the "Go Home" button. The application redirect me to the web browser instead of the home screen. I am tired to search a solution for that.
I am using the following code:
finish();
Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
startActivity(intent);
Thanks in advance, Siddiqui Noor

Your app is opening in the task of the browser. Try this:
finish();
Intent intent = new Intent(context, HomeActivity.class);
intent.setAction(Intent.ACTION_MAIN)
.addCategory(Intent.CATEGORY_HOME)
.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);

try adding FLAG_ACTIVITY_NEW_TASK:
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
and also try putting finish() after startActivity

I'm pretty sure that it's not really redirecting you anywhere, it's just closing the Activity. You call finish() after which the intent to start the activity never happens. The app is closed because you've finished the Activity and you end up looking at the screen that was showing before you opened the app. In this case, that is the browser.
Try removing the line to finish();

Intent intent = new Intent(Intent.ACTION_MAIN);
intent.addCategory(Intent.CATEGORY_HOME);
startActivity(intent);
kill your current activity after redirect the next activity
finish();

Launch activity from background app

I have my app running in the background and I want the app to be shown on the top(launched) of the android phone when the code below is ran. (I know the code is ran for sure)
This seems like a simple thing but I spent a couple hours on this site and everyone seems to be suggesting something like this:
Intent intent = new Intent(myActivity.this, myActivity.class);
startActivity(intent);
However, it is not bringing the app to the front and launching it.
I got it to work from a PendingIntent launched from a notification. Which I done by the code below. But I want the app to launch by itself without the user clicking on the notification.
Intent intent = new Intent(myActivity.this, myActivity.class);
PendingIntent contentIntent = PendingIntent.getActivity(this, REQUEST_CODE, intent, 0);
notification.setLatestEventInfo(this, "title", "msg", contentIntent);
I also tried:
Intent intent = new Intent("android.intent.action.MAIN");
startActivity(intent);
and flagging the intent:
intent.setFlags(Intent.FLAG_FROM_BACKGROUND);
intent.setFlags(Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
But doesn't seem to do anything, any help appreciated.

You should be able to call your own application like this:
Intent intent = new Intent("android.intent.category.LAUNCHER");
intent.setClassName("com.your.package", "com.your.package.MainActivity");
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
Edit: Forgot to add intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

From what I understand, you want a service that is running in the background and on a certain event, you want your application's activity to come in front i.e. on the users current screen whatever he is doing. It is not advisable to let a background service launch an application without a user's action. The android developer website says
A status bar notification should be used for any case in which a
background service needs to alert the user about an event that
requires a response. A background service should never launch an
activity on its own in order to receive user interaction. The service
should instead create a status bar notification that will launch the
activity when selected by the user.
Hence, do not try to make it launch on its own.

I An not behind my laptop atm so I am nog sure, but I think you have toe pass a context object hand then do context.startactivity(intent);
Sorry for not wel formated I am at my phone atm
Hope It helps

I am clutching at straws here, but you wrote:
MyActivity is launched first, then I either navigate to another app or just hit the home screen to have my app running in the background.
So the situation is that your original Activity is NOT running in the background, when you pressed HOME it might well could have been stopped and destroyed. Your background task remained orphan and MyActivity.this is null at this point.
Try and test what does Log.i(TAG,MyActivity.this); print into LogCat.

I ended up using a pending intent and instead of stright up trying to use a intent.
Something like this: seems a lot more simple.
Intent.send(this, 0, intent);
Thanks.

Also, I’ve seen since compileSdkVersion 29 it's not possible, unless a few restrictions:
The activity started very recently.
The app called finish() very recently.
Through a PendingIntent, but only after a few seconds after the notification was sent.
The app has been granted the SYSTEM_ALERT_WINDOW permission by the user.
...
https://developer.android.com/guide/components/activities/background-starts

Sending a running application to background programmatically

Is it possible to send a activity into background programmatically in android?
I am creating a prank application that plays funny sounds after a specified time (input by the user). And I don't want the application to be visible when playing that sound and also the display should be dark.

Yes.
You can use either:
boolean sentAppToBackground = moveTaskToBack(true);
if(!sentAppToBackground){
Intent i = new Intent();
i.setAction(Intent.ACTION_MAIN);
i.addCategory(Intent.CATEGORY_HOME);
this.startActivity(i);
}
More information here: http://developer.android.com/reference/android/app/Activity.html#moveTaskToBack(boolean)
Or simply:
Intent i = new Intent();
i.setAction(Intent.ACTION_MAIN);
i.addCategory(Intent.CATEGORY_HOME);
this.startActivity(i);
According to Romain Guy a Android Framework Engineer, "You cannot simulate a press on the Home key.". So beware...
Check: http://osdir.com/ml/Android-Developers/2010-03/msg01887.html
Updated this answer according to: moveTaskToBack(true) returns false always

This function ultimately works for you
moveTaskToBack(true)
Or download source code . Android minimize app programmatically

Maybe play the sound from a service instead?

To expand on the answer by #ns476, the reason you should play it from a service is that any Activity that is no longer in the foreground can be killed at any time by the OS. Please review the activity lifecycle.

Android: Starting An Activity For A Different Third Party App

I'm working on an app and I want to integrate the Last.fm app into it. Basically, when someone is looking at an artist in my app, I would like to have a button that they can tap to open up Last.fm application with the artist's information.
This intent works, but it loads a menu asking which app I would like to use (Browser or Last.fm):
Intent i = new Intent();
i.setData(Uri.parse("http://last.fm/music/" + headliner));
i.setAction("android.intent.action.VIEW");
startActivity(i);
However, I just want to start the Last.fm app and skip the dialog asking which app to use, I thought maybe using the setPackage() method would work like this:
i.setPackage("fm.last.android");
But it causes the app to crash:
android.content.ActivityNotFoundException: No Activity found to handle Intent { act=android.intent.action.VIEW dat=http://last.fm/music/Rihanna pkg=fm.last.android }
Is it possible to just start the Last.fm app? Here's a copy of Last.fm's AndroidManifest.xml for reference.
Thanks for reading,
Tony

Yes, it's possible but you need to know the correct component name. Launch the last.fm app regularly and check the logfile for the cmp=... information that's been used when the app is started. Use this as well in your app then.
I start the Z-DeviceTest app from the market from within my app without a problem like this:
final Intent intentDeviceTest = new Intent("android.intent.action.MAIN");
intentDeviceTest.setComponent(new ComponentName("zausan.zdevicetest","zausan.zdevicetest.zdevicetest"));
startActivity(intentDeviceTest);
in my case the info I took from the logcat was:
// dat=content://applications/applications/zausan.zdevicetest/zausan.zdevicetest.zdevicetest
// cmp=zausan.zdevicetest/.zdevicetest
in order to know how to start the app with the right component/class... do the same for the last.fm app
Edit:
I've tested to launch Last.fm from my own app, and this works fine without any errors:
final Intent intentDeviceTest = new Intent("android.intent.action.MAIN");
intentDeviceTest.setComponent(new ComponentName("fm.last.android","fm.last.android.LastFm"));
startActivity(intentDeviceTest);