为什么这个 Android 开发人员文档用两个 m 命名它的一些变量

Why does this Android developer doc name some of its variables with TWO m's

我了解背后的原因one m as a non-static, private variable. But what about when there are two m's as seen here

我不确定,但我怀疑它是为了表示一个子class私有非静态变量。