Sorry, my English is not good. How can I show fragments side by side so that when the user clicks a button in fragment A, fragment B is shown (80%)?

Sorry, my English is not good. How can I show fragments side by side so that when the user clicks a button in fragment A, fragment B is shown (80%)?

Go through the below links. It may help you
https://github.com/gitgrimbo/android-sliding-menu-demo
https://github.com/jfeinstein10/SlidingMenu
If you are looking to put a side menu in there that can be moved in and out you could try the Navigation Drawer by Google and it should do the job. Read about it here: Creating a Navigation Drawer
I assume that you want to display a fragment on a button click. You can simply use replace function to replace the fragment on button click like this:
FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.replace("layoutName",fragmentB)