问题
I don't know why but sometime in Android Studio Editor, it shows vertical line as shown in screenshot below.
Don't know about other editor but it happens in Android Studio.
So why it is showing and how to hide it?
回答1:
That line historically represents the margin of A4 paper, that is useful only if you need to print the code. Old school says that you should keep your code inside that margin, to guarantee much portability.
But.. nowadays in the real life it makes no sense to me! Because we always use advanced editors, bigger displays, and I never needed to print any single line of code..
So, if you want do it:
Newer versions
Editor -> General -> Appearance -> Show hard wrap guide
Older versions
Editor -> General -> Appearance -> Show right margin
or
Editor -> Appearance -> Show right margin
回答2:
It is as follows in the newer version of Android Studio:
Editor -> General -> Appearance -> Show hard wrap guide
来源：https://stackoverflow.com/questions/41585002/vertical-line-in-android-studio