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Android start activity of second app having no icon from first app

I am having two apps. First app has an activity from which I want to launch an activity from the second app. I am using the following code:
Intent launchIntent = m_context.getPackageManager().getLaunchIntentForPackage(m_packageName);
if (launchIntent != null) {
m_context.startActivity(launchIntent);
}
This code is working very fine to launch the activity from the second app but I want to have the second application without any icon. I am using following code in MainActivity of the second application to remove icon:
PackageManager p = getPackageManager();
//Removing app icon
ComponentName componentName = new ComponentName(this, com.tools.html2pdf.MainActivity.class);
p.setComponentEnabledSetting(componentName, PackageManager.COMPONENT_ENABLED_STATE_DISABLED, PackageManager.DONT_KILL_APP);
This code successfully removes the launcher icon but then activity from my first application is unable to launch the activity from second app.
Can any one help me in this regard? I want to launch activity of an app having no icon from activity of another application.

When you disable the component like you have done, that component can't be launched in any way. However, interesting thing is that other components (non-disabled activities) of your second application are still launchable.
So, you can create an alias of your MainActivity in the second application which will be used for your purpose. Let's call alias as MainActivityAlias.
From your first application, call the intent on MainActivity. The code for disabling the component will be executed and nothing will open. However, the icon will be gone because this component is disabled and everything related to this component (i.e icon) is gone too.
Now, call the intent on MainActivityAlias just after above intent in the first application. This is just a copy of MainActivity but it does not have any code for disabling and thus, it is enabled and launchable.
Some Side Notes :
1) Both activities should have an <intent-filter> with android.intent.action.MAIN.
2) Your MainActivity should be the launcher activity and thus should have android.intent.category.LAUNCHER in the manifest.
3) Inside MainActivity, you have to check where the call is coming from. If the call is from the first application, then execute the code to disable icon which you mentioned in the question. If the call is coming from launcher icon, then open MainActivityAlias using intent. You can know where the call is coming from like this.
Note - This is just an idea. I have not tested it.

If you don't want the second app to have an app icon, just remove the <intent-filter> with ACTION=MAIN and CATEGORY=LAUNCHER for the root Activity in the second app. When the app is installed, if there is no <intent-filter> with ACTION=MAIN and CATEGORY=LAUNCHER, there will be no app icon shown.
Your app can still launch the second app, but not with the method you've described, since Android doesn't know which is the "launch" Activity. Assuming you know the package and class name of the Activity you want to launch in the second app, you can launch it like this:
Intent launchIntent = new Intent();
launchIntent.setClassName("second.package.name", "fully.qualified.class.name.of.MainActivity");
// add and Intent flags if necessary here
launchIntent.addFlags(Intent.FLAG_ACTIVITY_...);
startActivity(launchIntent);

how to start launcher activity after app goes to background?

I want to always start launcher activity after app goes to the background. I tried android:clearTaskOnLaunch="true" but it not work. How can i do this? For example i have A,B,C,D,E,F activity. A is launcher activity.
now i open app so A activity is called then A>B>C. now i minimize the application. Now i open application from the icon so app is start from C but i want it start from A so how can i do this? some said use onResume intent with Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK. but what if i press back button then onResume is called and my app start with A activity.... so it is not work..any solutions???

You can check the App is in foreground or is in background and when the application goes to the background state at the same time do some logic that when your application comes to foreground it will always show the root activity.
How you can identify application is in which state is well explained here

When you start Activity B, use these flags. That way Activity B and C will always be in a separate stack. That means that when someone starts Activity A from the home screen they will see Activity A always.
Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK
Intent intent = new Intent(context, B.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK)
startActivity(intent);
Also this might help, you can add this flag to your root Activity.
<activity
android:name=".ui.MainActivity"
android:clearTaskOnLaunch="true"/>

This does because device store data about application. For short time data are stored. if you want to start application from rot class. use service with application, so that whenever your application goes in background and pause then choose your action to do that will be easier.

Android - Bring an activity to the front from application class

I am trying to bring an activity to the front. I found many questions similar to this but none of them actually works.
I always hold a reference to the current activity in a variable in application class. While the application is running in the background (after onPause fires), if any message arrives, I need to bring the same activity to the front and display the message. The only way I got it worked is..
Intent i = new Intent(mCurrentActivity, JoboffersActivity.class);
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(i);
The issue I have got with this, is that it recreates the activity which I wanted to avoid. I tried singleInstance and singleTask both in the manifest. If I do not add FLAG_ACTIVITY_CLEAR_TOP, on back key press it takes me to the previous instance of the same activity. Even if I add sigleInstance it creates two instances of the same activity. If I do not add FLAG_ACTIVITY_NEW_TASK then it shows an error Calling startActivity() from outside of an Activity context requires the FLAG_ACTIVITY_NEW_TASK flag

Try to add another flag FLAG_ACTIVITY_SINGLE_TOP to your intent.
According to Android documentation, combination of this 2 flags:
i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
brings the current instance of Activity to the front.
http://developer.android.com/reference/android/content/Intent.html#FLAG_ACTIVITY_CLEAR_TOP

Android - Call Main Class Activity

I would like to go back to the Main Activity at a certain point in my application. I tried calling the Activity in an Intent as usual, however since the Activity name for the main class is called "android.intent.action.MAIN", which is the general name of every application's main activity, a "Complete Action Using:" menu pops up with every possible application on the phone as an option. I do not want this; what I want is that the main activity for my application loads up.
How can I achieve this?
Thank you in advance!

You can also specify a specific Activity to launch like so:
Intent nextActivityIntent = new Intent(this, MyActivity.class);
startActivity(nextActivityIntent);
As per the Intent documentation, the ACTION_MAIN flag is used to specify that you want to launch an application using the application's main entry point. You generally do not use it in your app unless you are trying to open another app.

android - launchMode=singleTask and Notifications?

I know there's been a few posts for what I'm about to ask but I can't find any with the right answer.
From my understanding, if your main activity's (let's call it A) launchMode is set to singleTask, and A has initiated activity B then a click to the home button will destroy the history stack and re-launching the application will take you back to A and not B.
I have launchMode set to singleTask because I have a persistent notification and I don't want to have multiple instances of the main activity to appear whenever the user clicks on the notification.
Is there something I'm missing that would allow me to cater for both?
So I'm asking if there's a way I can ensure that whenever the user wishes to launch the app, from the notification or not, to take him back to the last (current) activity.
If I change launchMode to singleTop it works but I get multiple instances of the main activity whenever I launch it.
Thanks
Andreas

Have you tried setting launchMode to singleTop to all the activities in your app?? Because what i get from your query is that the main activity isn't singleTop, so that might lead to another instance of the main activity being called once the main activity is launched from the activity that was launched from the notification activity.
Or you can specify the launchMode as an attribute to the application tag itself in the manifest.

I use the following code to avoid multiple instances of the activity
Intent intent=new Intent(this,RICO.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP|Intent.FLAG_ACTIVITY_SINGLE_TOP);
PendingIntent contentIntent = PendingIntent.getActivity(this, 0, intent, 0);
Changing manifest doesn't look appropriate to me

I'm having issues with both the approches.
The notification works flawless only in this condition:
- using the back button in the main activity (with the history containing only the that activity)
- not using the Home button
- not using the notification IF the activity you are calling is on top and active
In any other case, the notification cannot anymore call on the foreground the activity by using "new Intent(...)"

I've found the alchemical combination of manifest options and intent's flags for getting what I needed:
Intent intent= new Intent(this, YaampActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
using these options
android:launchMode="singleTask"
android:taskAffinity=""
android:excludeFromRecents="true"
inside the element.
Now I've a notification which spawns the main activity (if that activity is not already in the foreground) and its behavior is correct even if the activity is "closed" by pressing the home button and/or the back one.