States

States are sets of layer properties and values. You can add, remove or switch between states. State switching can be done with or without an animation, and you can define different animation options for individual states too.
译：状态是一组层属性和值。您可以添加、删除或在状态之间切换。状态切换可以用或不使用一个动画来完成，你也可以定义不同的动画选项，为个别状态。