Question

我有三个fragments，它们使用新的导航组件版本，在其中您可以共享连接到某些流的ViewModel。无论如何，第三个fragment可以导航回到第一个，我需要清除ViewModel

我已经检查了this的答案，但是由于某种原因，viewModelStore.clear()并没有清除任何内容

第一个片段：

class FirstFragment : Fragment() {

    private val viewModel: ShareViewModel by viewModels()

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        //it does nothing
        viewModelStore.clear()
    }

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        //here the lpn must be null
        vehicle_lpn.text = (vehicle_lpn.text as String).plus(viewModel.vehicleLpn.value)
        button.setOnClickListener {
            viewModel.setVehicleLpn("Hey")
            findNavController().navigate(R.id.action_firstFragment_to_secondFragment)
        }
    }

}

第二个片段：

class SecondFragment : Fragment() {

    private val viewModel: ShareViewModel by navGraphViewModels(R.id.navigation_main)

}

第三片段：

class ThirdFragment : Fragment() {

    private val viewModel: ShareViewModel by navGraphViewModels(R.id.navigation_main)

    override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
        super.onViewCreated(view, savedInstanceState)
        vehicle_lpn.text = "VEHICLE LPN: " + viewModel.vehicleLpn.value
        button.setOnClickListener { findNavController().navigate(R.id.action_thirdFragment_to_firstFragment) }
    }
}

如何清除片段之间共享的ViewModel

0 个答案: