Develop Reference

Start Android Service with no Activity using an intent

i created an android application with no activity. I want to start a service using a system intent like BOOT_COMPLETED. I use the following receiver:
<receiver android:name=".autostart" >
<intent-filter>
<action android:name="android.intent.action.ACTION_POWER_CONNECTED" />
<action android:name="android.intent.action.ACTION_POWER_DISCONNECTED" />
<action android:name="android.intent.action.BOOT_COMPLETED" />
<action android:name="android.intent.action.SCREEN_ON" />
</intent-filter>
I got the problem, that the intent is not received when power is connected/disconnect or boot completed. Is an Application with no Activity even in stopped mode after install? How can I start the service? UI is not possible because the application has no activity...

Is an Application with no Activity even in stopped mode after install?
Yes.
UI is not possible because the applicatio has no activity...
Then add one. You need one anyway, to present your license agreement, your online help, your configuration for this background processing, and so forth. And, since your app will not run until the user launches this activity, you need to for that reason as well.

Every Android application needs to be launched at least once after installation and only then it will receive any intents from system. This means an application without any gui will not work in your case.
Many applications include only "about" activity, which is a common way to deal with that.
Please see:
http://commonsware.com/blog/2011/07/13/boot-completed-regression-confirmed.html
http://developer.android.com/about/versions/android-3.1.html#launchcontrols

Launching my app from Facebook messenger make it stay in Facebook activity

I'm recognizing special links to enable my users to launch my Android app when clicking on a link like "http://popp.us/ABCDE", for exemple from the Facebook messenger
For this, I implement in my Manifest file, inside my main activity tag :
<intent-filter>
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
<data android:scheme="http" android:host="popp.us" />
</intent-filter>
It correctly works, but when I click the home button and relaunch the Facebook app, Facebook is still showing my own app. It seems to have launched my main activity inside Facebook app task.
Does someone know a way to force Facebook (or other apps) to launch my app in another task ?

This is the default behaviour since Honeycomb and I strongly encourage you to keep it.
That said, you can escape the task by setting the launchMode <activity> attribute to singleTask or singleInstance. See the documentation for more info. This will require you to use a separate Activity for that intent-filter, since it would mess up the normal use of the Activity in your app.

How Launcher decides which app icon to place in launcher?

I have a very naive question. I've written a program which lists down all the installed applications in my Android OS [I've got total 339 in my case]. But in the Launcher [In my case TouchWiz Home] only 148 application Icons are shown.
My Question is: How does the launcher[TouchWiz Home] decide which app icon to show or not in Launcher?

Launcher will show those activities that have the following intent filters declared in the app's manifest file
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>

When a developer publishes an app, he/she can decide if app has "launcher" icon(set a launcher intent in manifest file which is embedded in the APK).
Other apps maybe services or other kind of apps that has no launching behavior.

How to open the application from my android application with no launcher

I have 3 android applications. One main application call other 2 applications (main application will be interface for other 2 applications). I would like to have only one icon of this main app. I have 3 applications they can be downloaded separately. Now I need the other applications to check if the main application is installed. If not, download and install main app. But how can I do that, if the secondary applications haven't got LAUNCHER ? Is there any way to do install main app from app without launcher ?
Main app has android manifest:
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
Secondary app has manifest (because do not want icon)
<intent-filter>
<action android:name="android.intent.action.MAIN" />
</intent-filter>
Yes I know how to use code in app where is launcher to check app is installed, but dont want how to operate with, when the launcher is not.
if (installed==false) {
Intent promptInstall = new Intent(Intent.ACTION_VIEW)
.setData(Uri.parse("https://play.google.com......))
.setType("application/vnd.android.package-archive");
startActivity(promptInstall);
Or second question: is it possible to install app with launcher and then uninstall/hide icon of this app ? Let's say simple I will install all aplications with launcher and then after installation and settings hide icon of app, so that stay only icon of main application.
It looks strange for me, there is not any simple way to do that, simple set if icon will be visible or not. The same as you install software on Windows and you can set during installation if icon will be visible on desktop.

Interact with Android Setup Wizard

I am trying to develop a setup wizard for Android, as I would like to add some functionality to the one existing from Google. Is it possible to somehow interact with the Android wizard? Because when I have searched for information I've seen that not using Google's Wizard might cause some trouble, regarding gmail account activation and so on.
If not, could an activity be called immediately before or after Google's wizard? Would it be enough to just listen to the BOOT_COMPLETED event?
Thank you very much in advance!

I don't know how you will use this unless you are making a rom and can add your app to system but basically you make your setupwizard add-on a Home activity with action MAIN, and categories HOME,DEFAULT. You should also set the priority higher than 1. If any of this is unclear you can look at the Launcher source/manifest that is publicly available.
When your activity is done it should deactivate itself with the PackageManager (setComponentEnabledSetting) and that should be it.

You can add additional activities that start the first time the phone is boot up. You just have to mimic the same behavior as Google's SetupWizardActivity.
Here's the relevant portion in the AndroidManifest.xml for reference:
<activity android:theme="#style/InvisibleNoTitle" android:label="#string/setup_wizard_title" android:name="SetupWizardActivity" android:excludeFromRecents="true" android:launchMode="singleTop" android:immersive="true">
<intent-filter android:priority="5">
<action android:name="android.intent.action.MAIN" />
<action android:name="android.intent.action.DEVICE_INITIALIZATION_WIZARD" />
<category android:name="android.intent.category.HOME" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
This will allow you to run your application before/after SetupWizardActivity, depending on your priority. I believe higher numbers for android:prioirity run first, but don't quote me on that.
You can find out the AndroidManifest xml for various Android-related apks using apktool. You can even inspect some of apks you picked up from the Play Store or whatever other sources.