[Unity] Some convenient knowledge of Unity operation

1. Press and hold Alt and then click the small triangle to the left of an object on the Hierarchy to expand all sub-contents under the object.
2. If you need to present some kind of dynamic icon effect, you can use the Slider component of the UI to delete all unnecessary Handle and Background, leaving only Fill, and then replace the default sprite with your own sprite to generate the shape, and finally set the fill mode.
3. If the Slider is only used as an animation icon and does not need to be actively manipulated by the user, uncheck Interactable and set Transition to None.
4. The specific way to replace the shape of the Slider is to replace the Fill sub-object in the Slider with a Sprite made by yourself.
5. Certain empty objects whose shapes cannot be seen directly, can set gizmos. A gizmo is a two-dimensional icon that shows the location and name of an object. The position is in the upper left corner of each object Inspector.
   
   The effect is like this