Why doesn't the "@string/" attribute not have a + sign?

Question

I know that the + sign in the id attribute of a View indicates that it's a new user defined custom value that must be added to the R.Java file. But, in the example XML Button View attributes below, why does the @string not have the + symbol before the word string like the @+id attribute?

<Button android:id="@+id/my_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/my_button_text"/>

@GabrieleMariotti But isn't that a custom string value that will be added to R.Java? So, that should require a `+` sign, right? — Raj Narayanan, May 07 '20 at 11:36
@Swifty No. The string already exists in the resource files (and then in R.string.xxx) — Gabriele Mariotti, May 07 '20 at 11:37
@GabrieleMariotti Do you mean that this is because the string resource is a predefined static value where as the id value in R.Java is volatile, requiring a rebuild every time the app is built and run in Android Studio? — Raj Narayanan, May 07 '20 at 11:40

IntelliJ Amiya · Accepted Answer · 2020-05-07T11:52:03.190

1

The plus symbol, +, indicates that this is a new resource ID and the Android Asset Packaging Tool will create a new resource integer in the R.java class, if it doesn't already exist.

@string - Defined in resource files. The <string> element's name is used as the resource ID.

edited May 07 '20 at 11:52

answered May 07 '20 at 11:45

IntelliJ Amiya

74,896
15
165
198

Why doesn't the "@string/" attribute not have a + sign?

1 Answers1