[android help] How to end a launcher completely?

My application works as a launcher. But, I guess I did something wrong by making it a launcher. For instance, the user selects my application as Default Launcher (clicks 'Always'). However, when the user exits from the application, it appears again, because it's the default launcher. How can I fix it?

      android:name="com.comeks.cocuktablet.Main"
      android:label="@string/app_name"
      android:launchMode="singleInstance"
      android:screenOrientation="portrait" >
      
           

           
           
           
      

The code comes from my manifest. I also want to make MAIN activity launcher.

Edit: I realized my exact error. I also wrote a code to start my app on boot. The problem is that when I close my device and open it again, I cannot exit from it.

.

stackoverflow.comm