android - 如何在对 recyclerview 项目执行单击时更新 viewModel 的实时数据

Question

我是 Kotlin 的新手，我正在尝试使用 MVVM 创建一个应用程序。所以我想做的是在存储库中使用改造进行网络调用，并将数据返回到 View 模型，然后观察 fragment 中的数据，一旦数据发生变化，我就会将它通知给回收器 View 适配器，一切都是工作正常。现在，问题是我想从 recyclerview 更新 ViewHolder 的实时数据。当我单击 recyclerView 中的 CheckBox 时，数据应该会更新。但我不知道这样做的实际方法是什么。

这是我的 ViewHolder。

class MainActivityViewModel : ViewModel() {

private var mutableLiveGitUsers: MutableLiveData<ArrayList<GitUsers>>? = null
private lateinit var gitUsersRepository: GitUsersRepository
var allUsersListener: AllUsersListener? = null

fun init() {

    gitUsersRepository = GitUsersRepository()
    allUsersListener?.onStarted()
    mutableLiveGitUsers = gitUsersRepository.getGitUsers()
    allUsersListener?.onSuccess(mutableLiveGitUsers!!)
}

fun getGitUsersData(): MutableLiveData<ArrayList<GitUsers>>? {
    return mutableLiveGitUsers
}

这是我观察 fragment 变化的方式

mutableLiveGitUsers.observe(this, Observer {
        progressBar.hide()
        rvAllUsersAdapter = AllUsersAdapter(mainActivityViewModel.getGitUsersData()?.value!!)
        rvAllUsers.adapter = rvAllUsersAdapter
        rvAllUsersAdapter.notifyDataSetChanged()
    })

RecylerView 适配器

class AllUsersAdapter(private var gitUsersArrayList: ArrayList<GitUsers>) :
RecyclerView.Adapter<AllUsersAdapter.AllUsersViewHolder>() {

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): AllUsersViewHolder {
    val inflater: LayoutInflater = LayoutInflater.from(parent.context)
    val v: View = inflater.inflate(R.layout.items_all_users, parent, false)
    return AllUsersViewHolder(v)
}

override fun getItemCount(): Int {
    return gitUsersArrayList.size
}

override fun onBindViewHolder(holder: AllUsersViewHolder, position: Int) {

    holder.tvUserName.text = gitUsersArrayList[position].login

    Glide.with(holder.itemView.context)
        .load(gitUsersArrayList[position].avatarUrl)
        .centerCrop()
        .into(holder.imageView)

    holder.checkBox.isSelected = gitUsersArrayList.get(position).isSelected

    holder.checkBox.setOnCheckedChangeListener{compoundButton, isChecked ->

        if (isChecked){
    /* Here I want to change the live data so I can observe that changes in my 
fragment and can have an effect in UI*/

            Log.d("TESTC","AllUsersAdapter IsChecked")
        }else{
            Log.d("TESTC","AllUsersAdapter UnChecked")
        }
    }

}

class AllUsersViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {

    var tvUserName: TextView = itemView.findViewById(R.id.tvUserName)
    var imageView: ImageView = itemView.findViewById(R.id.imageView)
    var checkBox: CheckBox = itemView.findViewById(R.id.checkBox)
}
}

Answer 1

1. 向您的适配器引入项目点击回调:

class AllUsersAdapter(private var gitUsersArrayList: ArrayList<GitUsers>,
 private val itemClickCallback: ((Boolean) -> Unit)?) :
RecyclerView.Adapter<AllUsersAdapter.AllUsersViewHolder>() {

override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): AllUsersViewHolder {
    val inflater: LayoutInflater = LayoutInflater.from(parent.context)
    val v: View = inflater.inflate(R.layout.items_all_users, parent, false)
    return AllUsersViewHolder(v)
}

override fun getItemCount(): Int {
    return gitUsersArrayList.size
}

override fun onBindViewHolder(holder: AllUsersViewHolder, position: Int) {

    holder.tvUserName.text = gitUsersArrayList[position].login

    Glide.with(holder.itemView.context)
        .load(gitUsersArrayList[position].avatarUrl)
        .centerCrop()
        .into(holder.imageView)

    holder.checkBox.isSelected = gitUsersArrayList.get(position).isSelected

    holder.checkBox.setOnCheckedChangeListener{compoundButton, isChecked ->

        if (isChecked){
    /* Here I want to change the live data so I can observe that changes in my 
fragment and can have an effect in UI*/

            Log.d("TESTC","AllUsersAdapter IsChecked")
 itemClickCallback?.invoke(true)
        }else{
            Log.d("TESTC","AllUsersAdapter UnChecked")
 itemClickCallback?.invoke(false)
        }
    }

}

class AllUsersViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {

    var tvUserName: TextView = itemView.findViewById(R.id.tvUserName)
    var imageView: ImageView = itemView.findViewById(R.id.imageView)
    var checkBox: CheckBox = itemView.findViewById(R.id.checkBox)
}
}

1. 在您初始化适配器的 fragment onViewCreated() 中处理点击事件

 val rvAdapter = AllUsersAdapter(
            gitUsersArrayList = gitUsersArrayList, itemClickCallback = fun(status: Boolean) {
                navController().navigate(
                    viewModel.updateValue(status)
                )
            }
        )

1. 创建所需的 ViewModel 函数:

class MainActivityViewModel : ViewModel() {

private var mutableLiveGitUsers: MutableLiveData<ArrayList<GitUsers>>? = null
private lateinit var gitUsersRepository: GitUsersRepository
var allUsersListener: AllUsersListener? = null

fun init() {

    gitUsersRepository = GitUsersRepository()
    allUsersListener?.onStarted()
    mutableLiveGitUsers = gitUsersRepository.getGitUsers()
    allUsersListener?.onSuccess(mutableLiveGitUsers!!)
}

fun getGitUsersData(): MutableLiveData<ArrayList<GitUsers>>? {
    return mutableLiveGitUsers
}

fun updateValue(status: Boolean) {
//@Todo Set new value based on status received
     // mutableLiveGitUsers.value = 
}
}