How to refresh preview on Android Studio 2.2?

Refresh feature is not removed, it is there; It's pretty simple to refresh:

Click on the preview screen to make sure preview window has the focus and press R. It should display the progress in the right-top corner while refreshing.

If it doesn't work for any reason, switch to design tab and press R, it refreshes the layout instantly.

I think it is a small bug. But I find a hack solution to resolve the problem, you can modify the a resource id to a wrong name, for example, you have a resource named 'ic_launcher', when you input 'ic_launcher1', you can find the interface like that:

next step, click refresh icon(sometimes it is 'clear cache' label). it is works for me.

I have try to change the orientation, but it not works when I replace a exist image file.

May your problem is same as : http://stackoverflow.com/questions/39646639/android-studio-2-2-layout-editor-refresh-button

Display again?

I guess you cant. Apparently the refresh functionality has been removed because they think the processing will happen much faster and will auto-refresh the previews real time. The Layout Editor's document has no mention of refresh functionality.

Shortcut?

If you are faster in making changes to your layout than Android-studio refreshes, you could try toggling between the design and blueprint views using the shortcut B

Refer the Layout Editor Official Documentation for other shortcuts you might feel comfortable with or works for you.