Your First Kotlin Android App: An App From Scratch, Episode 7: Continue Building the UI |

Continue building the game screen and learn about working with xml in the code view of the layout designer.

This is a companion discussion topic for the original entry at

In the XML layout (near the end of the video, starting at about the 4:30 mark) some of the TextView constraints are to “@+id/seekBar” and some are to “@id/seekBar” (and equivalent)
As I understand it, it probably doesn’t matter, but it’s likely to be confusing to anyone who is watching closely.

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Good catch here :+1:

In our case here, there is not much difference.

Using the @+id/viewName, you’re telling Android that you’re creating/accessing a resource you created and if it is not in the R file then it should be added to that file.
In our case, @+id/seekBar has already been created previously and has been added to the R file so it exist there.

This means you can simply access it using @id/seekBar

It’s best to always use @+id/seekBar just in case you’re entering the xml manually.
By adding the + sign, you wont encounter any compile errors related to accessing a resource that does not exist in the R file.

Note: The R file is automatically generated for you and it contains unique integer ids for your resources.

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