Android Getting Started-id

@+id/btn//indicates that a new control index with ID btn is added to the R.java file, the most common way to declare a control ID.

@+android:id/list//+android: Indicates reference to Android. R.id inside the ID resource defined, if android.r.id inside does have the title of this ID resource, directly use it, if not, in the current application of the r.id to produce a title identifier

@id/btn//indicates a reference to an already existing ID, in R.java, such as we built a ids.xml, which declares a set of IDs, one of which is btn, then you can refer to the

@android: Id/tabhost//refers to the system's existing ID, in the corresponding SDK directory Ids.xml inside. The general external does not go to call, is the component internal call when used

Android Getting Started-id