startActivity opens last app in background instead of needed activity - android

I got an app which can receive an event (which is basically a message from a service in the background), and when it does, I am invoking this code:
Intent dialogIntent = new Intent(this, MainActivity.class);
dialogIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
dialogIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(dialogIntent);
This code is supposed to return the app to the front so the user can handle the event.
This code works only if the app I'm working on was also the last app the user has been in. The code doesn't work in these scenarios:
1) The user has paused the app, opened another app and then paused it too so the 2nd app is the last in the background - in which case the last app will always open, even though I'm starting my MainActivity. For example, if I've moved my app to the background, opened Android's settings and then an event is received, the Android's settings screen will open instead of my app.
2) The user is inside another app. In which case, the app won't be brought to the front at all.
How can I made the specific app to be resumed from the background no matter what?

Use launcher category as below:
Intent resumeIntent = new Intent(context, MainActivity.class);
resumeIntent.setAction(Intent.ACTION_MAIN);
resumeIntent.addCategory(Intent.CATEGORY_LAUNCHER);
startActivity(resumeIntent);
Also add android:launchMode="singleTop" in the manifest of your activity.

You can add android:launchMode="singleTop" in the manifest for the Activity.

Related

How do I return to previous app after a service generated activity is 'finished'

My app has a service that runs in the background. It wakes up on intent from the user which is typically generated from another application (such as sharing to my app from the web browser). After the service is done performing a task I want it to open an Activity that displays some info about the task that was completed. When the user is done looking at this info, I want them to be able to hit 'Back' or 'Close' and return to what they were doing previously (not within my application).
I've only managed to get the activity to close leaving my App's main activity front and center on the screen. This only happens if the app is still running. If it's been killed then it correctly returns to the web browser where the user intent was generated from.
How can I make the 'Back' button close the activity and return to the previous app from which this entire workflow was started?
EDIT:
This is the code I am executing from within the android service:
Intent intent = new Intent(this, TestActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
When I tap the back button from the TestActivity it returns me to the main activity of my app, not the previous app I was in when the service started TestActivity.
In second line you are using Intent.FLAG_ACTIVITY_CLEAR_TOP which is clearing your previous activity

Can the Google SMS Messenger app be launched without animation?

I am trying to launch the Google's SMS Messenger app from my activity without any animation. I tried adding the flag FLAG_ACTIVITY_NO_ANIMATION while launching it. But still it launches with that default animation (my activity is pushed to the background and the new activity launches from bottom of the screen). I am not sure if I am doing something wrong here or it is a problem with the Messenger app itself, that it is not honoring that flag.
Code below:
Intent intent = new Intent(Intent.ACTION_VIEW);
intent.setData(Uri.parse("sms:222222222"));
intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
startActivity(intent);
Have also tried adding the below line after the activity was started, but doesn't help.
overridePendingTransition(0,0);

More than one instance of activity due to intent

For an App I am developing, I override the back button to make it act like the home button so that the state of the main activity is preserved even when the app is exited. Now, I also send a notification to the user from time to time using a service. When this notification is pressed I want to open the main activity again. I noticed though that this creates a second instance of the app, which creates major problems. I am trying to make the main activity go to the front again, without calling oncreate again like so:
Intent to launch main activity again:
Intent notificationIntent = new Intent(this, MainActivity.class);
notificationIntent.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT);
This doesn't work though. I still end up with two instances of my main activity. Does anybody know how to fix this?
By the way, I already have android:launchMode="singleInstance" in my manifest.
There's a way to force the OS to create only one instance of an activity and thats using the tag launchMode in the Manifest as shown below:
<activity android:name="YourActivity"
android:launchMode="singleInstance"/>
Hope this Helps...
Regards
Try adding this flag to the intent .addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP), works for me.

App also terminates when "end" button is pressed for coming back from GPS settings

I want some directions here. I have 3-Activities in an app i.e. MainActivity, MapViewActivity and DbActivity. I goes from one activity to another via. intents. The code of each intent is:
Intent intent = new Intent(this, ActivityName.class);
startActivity(intent);
I have used
android:noHistory="true"
in all these activities, so that when the mobile "end" button is pressed the app gets stop. Otherwise app was going back..... in spite of stoping the app
Now the problem is: When app goes for the GPS settings after finding GPS service off, the user turns on GPS and presses the mobile "end" button to come back to the app. But app also get stop. So user again start the app and comes on MapViewActivity. If I remove android:noHistory="true" from MapViewActivity, the problem also comes back. So is there any other solution for. Please guide me, if there is some method...
I don't think you mean "end". You probably mean "back". If you don't want the user to return to the activity when the user clicks "back", then just call finish() after you start the next activity. Like this:
Intent intent = new Intent(this, ActivityName.class);
startActivity(intent);
// finish this activity so that the user doesn't come back to it
finish();
Please take out the android:noHistory="true" from the manifest, this probably isn't what you want.

Activity not being reused

I have an odd issue with my application.
I start the application and the activity shows ok.
I then press the home key so that the activity goes into the background. I can see the onPause() method being called.
The application's service then creates a notification which shows on the status bar.
I then click on the notification and the activity is shown and I see that the onResume() method is called.
I then press the home key and the activity goes into the background. I can see the onPause() method being called.
If I now start the application by clicking on the applications icon I see that a new instance of the activity is created rather than using the paused instance.
If I press the home key again the new activity goes into the background.
Starting the application by clicking on the applications icon I see another new instance of the activity is created.
Pressing the back button at the point destroys each activity in return.
What I want to happen is that a single instance of the activity be used.
Any ideas?
Just use the same intent filters as android uses when launches the app:
final Intent notificationIntent = new Intent(context, MessageListActivity.class);
notificationIntent.setAction(Intent.ACTION_MAIN);
notificationIntent.addCategory(Intent.CATEGORY_LAUNCHER);
As the intent you created to open your activity from notification bar is the same as android used for launching your app, the previously opened activity will be shown instead of creating a new one.
You should look at the different launch modes for Android activities. this should help. Launch modes can be set in the androidmanifest.xml file. I think your solution would be to use the 'singleTop' launch mode.

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