1: About breakpoints
It is impossible to set the breakpoint triangle, this is the original saved App file running in the virtual machine, you can only click the second debug button.
This button allows the program to enter the current breakpoint in time
2: For background color
android:textColor="@color/white"
This @color is not a file name, it is a name defined under the file name <color> is an address @ Find the place where this color is defined
app\src\main\res\values\colors. xml is actually defined in a file in this directory
to be continued