Tip: Installed Application Not Installed Error

Have you ever loaded up an application, ready to debug, but then seen a message along the lines of, "Application Not Installed" display? This usually has an accompanying LogCat error:

ActivityManager: java.lang.SecurityException: Permission Denial: starting Intent

The cause and solution are very simple:

• This error is most likely caused by a duplicate Activity class entry in the manifest file. 

 <activity  
   android:name=".MainActivity"  
   android:label="@string/app_name">  
   <intent-filter>  
     <action  
       android:name="android.intent.action.MAIN" />  
     <category  
       android:name="android.intent.category.LAUNCHER" />  
   </intent-filter>  
 </activity>  
 <!-- lots of stuff -->  
 <activity  
   android:name="MainActivity"></activity>  

The solution should be clear by now:

• Remove the duplicate tag from the AndroidManifest.xml file 
• Build the application again
• Reload the application

This is quite the opposite of forgetting to add an Activity class to the manifest file. And, yet, it leads to a failure just the same. Proper maintenance of the manifest file is important. It's not a file to mess around with.

Happy Android Coding!