If ConstraintsSet is empty, it takes all the constraints defined in your layout xml file.

@@xBlaqs But it's the end result. Not the beginning. Wouldn't it make more sense to have those set in the beginning, and animate to the new state that it more defined? Or both ways are possible? Meaning that for both start and end state, they take all from the layout xml as default, and only if you change, it changes for where you've put the values?

@@LiranBarsisa That's right. It's default for both. I think sometimes it's easier to animate to your target state. Go to 2:00. It's all explained in the video.

@@xBlaqs OK thanks. I do wonder though: Do app developers use this mechanism a lot? Sure it could be nice in some cases, but in others I might think "That's too much for something simple". I once asked about adding some basic functionality of ViewAnimator/ViewSwitcher (to switch easily between states of loading and showing content), and was told that those aren't recommended to be used, but I don't get how I could have used something more suitable, as there aren't always moving parts that I need/can animate between them. Just switching of views...