Xmlns in xml in the Android layout file: Role of androidxmlns

Xmlns in xml in the Android layout file: Role of androidxmlns

Some new users often see the layout file has xmlns: android = "http://schemas.android.com/apk/res/android" or xmlns: tools = http://schemas.android.com/tools but do not know what it means.

In fact, it tells the Android development tool that you are going to use some common attributes in the Android namespace. This tree is required for the outermost tag in all Android XML design files.
It prompts you what you enter, what you do not enter, what is right, what is wrong, can also be understood as a syntax file. Or a syntax judge.