Difference between “@id/” and “@+id/” in Android

Question

What is the diffirence between the @id/ and @+id/?

In @+id/ the plus symbol

Answer 1

In Short

android:id="@+id/my_button"

+id Plus sign tells android to add or create a new id in Resources.

while

android:layout_below="@id/my_button"

it just help to refer the already generated id..