Components

Openintents Notepad is an open source application notepad that is provided with the Android. Openintents Notepad allows users to create, edit, send, and delete notes. But does not have a undo redo feature.

Proposal

my suggestion for notepad app, the developer should add undo and redo feature.
Undo is a command to cancel a command that has been done before.
Redo is a way to repeat something that has been canceled before.
The redo command is the reverse of the Undo command, the redo command serves to return a canceled command using the Undo command.

Benefits

Benefit of this feature, the user can cancel the command that has been done before. And the user can also repeat something that has been canceled before.
So in conclusion Undo command is used when you want to cancel a command that you have previously done, but with the record commands are not yet save.
While the redo command is used to undo the Undo command.