从RecyclerViewAdapter获取项目的默认值

Question

我有一个活动，有一个recyclerview。recycleview的每一项都有3个组件:spinner, EditText和ImageButton

在活动中，有一个"添加用户"按钮，应该保存所有的信息在recycleViewer到DB。为了提供更多的上下文，还有一个"添加用户"。按钮，将另一项添加到recycleViewer。

问题是，当我从活动中调用saveUsers函数时，谁调用newUserAdapter.getUsers()，该函数总是返回RecycleView空的项目列表(editText和Spinner)，即使用户修改了RecycleView

上的信息这是我的活动

class AddUser : AppCompatActivity() {
private lateinit var binding: ActivityAddUserBinding
private lateinit var newUserAdapter : AddUserRecyclerViewAdapter
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = ActivityAddUserBinding.inflate(layoutInflater)
newUserAdapter = AddUserRecyclerViewAdapter()
val b = User("","")
newUserAdapter.addItem(b)
binding.recyclerViewUser.adapter = newUserAdapter
setContentView(binding.root)
}
fun addNewUserRow(view: View) {
Timber.i("AddUser addNewUserRow called")
val b = User("","")
newUserAdapter.addItem(b)
}

fun saveUsers(view: View) {
if(newUserAdapter.itemCount > 0)
{
var usr = newUserAdapter.getUsers()
//TODO: save usr to DataBase
}
else
{
Snackbar.make(view, R.string.delete_user, Snackbar.LENGTH_LONG).show()
}
}
}

这是我的用户数据类:

data class User (
var name: String = String(),
var department: String = String()
)

和我的RecycleViewAdapter:

class AddUserRecyclerViewAdapter : RecyclerView.Adapter<AddUserRecyclerViewAdapter.AddUserViewHolder>() {
private var allUsers = ArrayList<User>()
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): AddUserViewHolder {
Timber.i("User onCreateViewHolder")
val view = AddUserItemBinding.inflate(
LayoutInflater.from(parent.context),
parent,
false
)
val tempUser = AddUserViewHolder(view)
tempUser.deleteBtn.setOnClickListener {
Timber.i("NewUser setOnClickListener " + tempUser.bindingAdapterPosition)
if (this.itemCount > 1)
{
deleteItem(tempUser.bindingAdapterPosition)
}
else
{
//At least one item, we don't let delete the last one
Snackbar.make(it, R.string.delete_user, Snackbar.LENGTH_LONG).show()
}
}
return tempUser
}
override fun onBindViewHolder(holderUser: AddUserViewHolder, position: Int) {
Timber.i("NewUser onBindViewHolder $position")
val item = allUsers[position]
holderUser.nameEt.setText(item.name.toString())
}
private fun deleteItem(pos: Int) {
Timber.i("NewUser deleteItem $pos")
allUsers.removeAt(pos)
// call notifyDataSetChanged() to notify our adapter.
notifyItemRemoved(pos)
}
fun addItem(item: User) {
allUsers.add(item)
// call notifyDataSetChanged() to notify our adapter.
notifyItemInserted(allUsers.size -1)
}
fun getUsers(): ArrayList<User> {
return allUsers
}
override fun getItemCount(): Int {
Timber.i("NewUser getItemCount called" + allUsers.size)
return allUsers.size
}
inner class AddUserViewHolder(binding: AddUserItemBinding) :
RecyclerView.ViewHolder(binding.root) {
var nameEt: EditText = binding.etName
var deleteBtn : ImageButton = binding.btnDelete
var spinnerDepartment : Spinner = binding.spinnerDepartment
}
}

编辑

似乎有人因为缺乏信息而拒绝投票，让我用不同的话来说。这是RecycleViewAdapter中的函数:

fun getUsers(): ArrayList<User> {
return allUsers
}

从活动中单击按钮时调用的对象:

fun saveUsers(view: View) {
if(newUserAdapter.itemCount > 0)
{
var usr = newUserAdapter.getUsers()
//TODO: save usr to DataBase
}
else
{
Snackbar.make(view, R.string.delete_user, Snackbar.LENGTH_LONG).show()
}
}

所以var usr是我得到空用户列表的地方，我希望得到一个用户列表，其中的信息填充在RecycleView中。

Answer 1

当你用addTextChangedListener更改文本时，你应该在ArrayList中更新用户的属性

override fun onBindViewHolder(holderUser: AddUserViewHolder, position: Int) {
Timber.i("NewUser onBindViewHolder $position")
val item = allUsers[position]
holderUser.nameEt.setText(item.name.toString())
holderUser.nameEt.addTextChangedListener(object : TextWatcher {
override fun afterTextChanged(p0: Editable?) { }
override fun beforeTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) { }
override fun onTextChanged(text: CharSequence?, p1: Int, p2: Int, p3: Int) {
// Update user instance in allUsers
allUsers[position].name = text.toString()
}
})
}

你可能还想在Spinner上定义一个onItemSelectedListener来更新所选的部门。