ViewModel

What is the ViewModel

• A data store component with host lifecycle awareness

• The ViewModel holds data that persists after the page is destroyed and rebuilt due to configuration changes

  Configuration changes: horizontal and vertical screen switch, resolution adjustment, permission change, system font style change

The use of the ViewModel

Changed the implementation principle of ViewModel reuse

ViewModel data reuse advanced SaveState

• SavedStatedHandle Data storage and recovery. Even if the ViewModel is not the same instance, the data it stores can be reused
• SavedStateRegistryController: used to create SaveStatedRegistry
• SavedStatedRegistry Data storage and recovery center.
• SavedStateHandle: Single ViewModel data storage and recovery.