R.id.myView 指的是什么？

Question

你能告诉我这个名字的三个单一组成部分指的是什么吗？

R.id.myView

Answer 1

R - R.java is an auto-generated file by aapt (Android Asset Packaging Tool) which contains resource IDs for all the resources of res directory.

public final class R 
extends Object 

.id - Find view using its id "defined by you"

public static final class R.id 
extends Object 

myView - It is the view that you defined using the android:id="@+id/your_view" attribute in your XML file.

So, finally we can find or identify any view using R.id.your_view.

Answer 2

android.R -R is a final public class in android. It extends Object class and it has many nested classes like R.id , R.anim , etc.

R.java is Automatically System generated file and contains the id of each resources used in the Application which is used to make reference. R.class contains IDs for all your android resources.

android.R.id is a nested class of R class. It has many static final constants like text1 , toggle , button , etc.

android.R.id.myView is an identifier of a View class. It represents an id for corresponding view defined in XML.

Answer 3

Android R.java is an auto-generated file by aapt (Android Asset Packaging Tool) that contains resource IDs for all the resources of res/ directory.

Whenever you use any recourse in you project then its one Unique Id will be generated automatically and you can identify that resource by using that id. You can not delete this file.

R :- Java class is collection of your all resources with its related id.

id :- Whenever you create any resource and assign the id by using @+id then R file create one unique id for that resource.

myView :- Its view id name that user can identify and By using that view id name we can identify that view in activity java file.

Below are the example of view id's in R.java file. If you want to show that where it is located then check this answer.

Example of R.Java file

public final class R {  
    public static final class attr {  
    }  
    public static final class drawable {  
        public static final int ic_launcher=0x7f020000;  
    }  
    public static final class id {  
        public static final int menu_settings=0x7f070000;  
    }  
    public static final class layout {  
        public static final int activity_main=0x7f030000;  
    }  
    public static final class menu {  
        public static final int activity_main=0x7f060000;  
    }  
    public static final class string {  
        public static final int app_name=0x7f040000;  
        public static final int hello_world=0x7f040001;  
        public static final int menu_settings=0x7f040002;  
    }  
    public static final class style {  

        public static final int AppBaseTheme=0x7f050000;  
        public static final int AppTheme=0x7f050001;  
    }  
}