问题描述:

Possible Duplicate:

Understand the R class in Android

I cant understand why use 'R' Class in android application.

 setContentView(R.layout.main);

Can explain why use R used here.

网友答案:

Your question is duplicate of Understand the R class in Android

When your application is compiled, aapt generates the R class, which contains resource IDs for all the resources in your res/ directory. For each type of resource, there is an R subclass (for example, R.drawable for all drawable resources) and for each resource of that type, there is a static integer (for example, R.drawable.icon). This integer is the resource ID that you can use to retrieve your resource.

I got this detail from the below link ,check this once for more details : http://developer.android.com/guide/topics/resources/accessing-resources.html

网友答案:

R.java which is Automatically System generated file it contains the id of each resources used in Application which is used to make refrence.

网友答案:

R.class contains IDs for all your android resources.

网友答案:

You can find more info here: http://developer.android.com/reference/android/R.html

网友答案:

R.class holds reference for all your android resources.. without which you cannot access any resources (drawable, layout, xmls etc) And R.class is Autogenerated.

网友答案:

R is the class that contains all the resource ids for your application.

网友答案:

Its a resource class, contains ID for for all resources. Here you can also use

 setContentView(main);
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