how to create a menu button like google keep app android, with action: after pressing the menu button show the other options of menu.
how keep the menu button be always visible on the screen?
how to create that effect after the click?
this image can clarify things https://drive.google.com/file/d/0B9ZjtpUDZajFNFM2bnBuOTNsX2c/view?usp=sharing
If you are talking about a floating action button (elevated circular button at the bottom rigth), this library provides a nice implementation of it called
FloatingActionsMenu. You can find some other libraries as well like this.
Take a look at Android Guidelines by Google.