在Eclipse中运行Android应用程序会导致NullPointerException

Question

I have been following the Android getting started docs and when I try to run the project I get:

!MESSAGE An internal error occurred during: "Launching HelloAndroid".
!STACK 0
java.lang.NullPointerException
        at com.android.ide.eclipse.adt.internal.launch.AndroidLaunchController.launch(Unknown Source)

The application doesn't launch.

Answer 1

On Top Menu go to "Run" then "Run Configurations" and select your target virtual device. Click apply, and then run the project.

Answer 2

Unplugging my Nexus One and restarting Eclipse fixed the problem. Not sure why.

Answer 3

1. Launch ADV Manager, verify if there is an AVD for your Android Project target else create an ADV for your Target (Click on New... button, enter a Name, select your Target then press Create ADV button)
2. Run Eclipse, right-click on your Android Project name in the Package Explorer window
3. Select Properties or press Alt+Enter
4. Click on Run/Debug Settings then select your project name and click Edit
5. Select Target tab
6. Click on Automatic and press Refresh button (If you have more AVD for the same Target: Select the checkbox the ADV verified or created at point 1) then click on Manual value)
7. Press Apply button then OK button

Now you can run or debug your Android Project.

Answer 4

Most likely you need to delete the existing launcher and recreate it as described in the other answers. You probably did some kind of refactoring or editing of the manifest file and the run configuration for some reason was not automatically updated. Maybe because your Eclipse plugin or SDK are outdated.