In the folder “res" we can find different sub-folders. When we create a new Android app, we have only 3 resources folders:
Drawable: In this folder, all images are stored. We can use them in code with the R.drawable.imagen_name sentence.
Layout: Here, different .xml are stored. These XML files define one or more elements that can be placed on the screen. As we can see in the image, the main.xml contains a black screen with the text “Hello, Test". In the .xml we see how this is codified. In following tutorials, we will see what all these tags mean. For now, see that we have a “LinearLayout" and inside it a “TextView". LinearLayouts are containers of others elements like, in this case “TextView". As you can imagine a “TextView" holds text. There are many other elements like “ImageView","Button" or “CheckBox". We can use all these elements and much more to create our application.
Values: In this folder we can hold, in an .xml file, all the strings we are going to use in our application, for example, or create an .xml to add our own styles to the elements we are using in the screen. In the image we can see how to define the strings. These strings will be accessible in the code using the resources file (R.java).