2.8 overview of ViewModel knowledge

One 、 Based on using

Belong to lifecycle Part of the component library

    implementation 'androidx.lifecycle:lifecycle-viewmodel:2.3.0-alpha05'
    implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.3.0-alpha05'

1. Inherit viewmodel/ or androidViewModel

2. stay Activity/Fragment Use in

   ViewModelProviders.of(getActivity()).get()
   by viewmodel

3. Life cycle auto sensing

   onClear Callback functions handle resource recycling closeWithRuntimeException

   ViewModel Never quote View、Lifecycle Or anything that may contain a pair of Activity Class referenced by context

4. 

5. be used for fragment Data sharing between

6. viewmodel+livedata+room Data perception , draw UI