Could not identify launch activity: Default Activity not found Error while Launching activity Failed to launch an application on all devices

This error typically occurs when Android Studio is unable to identify the default activity for the application. The default activity is the entry point of the application and is specified in the AndroidManifest.xml file.

To fix this error, follow these steps:

1. Open the AndroidManifest.xml file in the project.

2. Locate the <activity> tag for the default activity.

3. Ensure that the "android:name" attribute is set to the correct activity class.

4. Check that the activity class is properly defined in the project and is included in the correct package.

5. Ensure that the "intent-filter" tag is correctly defined for the default activity.

6. Check that the "category" attribute of the "intent-filter" tag is set to "android.intent.category.LAUNCHER".

7. Save the changes to the AndroidManifest.xml file.

8. Clean and rebuild the project.

9. Ensure that the device or emulator is properly configured and connected to Android Studio.

10. Try launching the application again.

If the error persists, try restarting Android Studio and/or the device/emulator. If the issue still persists, try creating a new project and copying the code over to the new project.