LiveData在RecyclerView中的观察者-高岭土
LiveData在RecyclerView中的观察者-高岭土
提问于 2021-04-09 16:11:28
如何在回收器视图中实现LiveData观察者？我有一个全局var‘`someDataChanged’，它是从另一个片段中更新的。任何帮助都将不胜感激！
class GlobalActivity {
companion object {
someDataChanged = MutableLiveData<Int>()
}
}然后在用于Adapter.kt的RecyclerView中，我需要侦听如果是someDataChanged。我有以下代码：
Adapter.kt
var mRecyclerView: RecyclerView? = null
class MainAdapter(val myResponse: MyResponse): RecyclerView.Adapter<CustomViewHolder>(){
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): CustomViewHolder {
//Error: this is not recognized.
GlobalActivity.someDataChanged`.observe(this, Observer{
println("Data Changed")
})
val layoutInflater = LayoutInflater.from(parent?.context)
val cellForRow = layoutInflater.inflate(R.layout.my_custom_cell, parent,false)
return CustomViewHolder(cellForRow)
}
override fun onBindViewHolder(holder: CustomViewHolder, position: Int) {
//some code
class CustomViewHolder(val view: View, var myPass: Passes? = null): RecyclerView.ViewHolder(view){
}
}
}回答 2
Stack Overflow用户
发布于 2021-04-09 16:35:08
不确定我是否理解您的问题，但是如果您想每次更新liveData时更新您的回收器视图，您应该创建如下所示：
class MyActivity : AppCompatActivity() {
private val viewModel: MyViewModel by viewModels()
lateinit var adapter: MyAdapter
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
adapter = MyAdapter()
recyclerView.adapter = adapter
viewModel.myLiveData.observe(this, Observer { newContent ->
adapter.updateContent(newContent)
})
}
}
class MyViewModel: ViewModel() {
private val _myLiveData = MutableLiveData<String>()
val myLiveData: LiveData<String> = _myLiveData
// You should call this to update you liveData
fun updateInfo(newInfo: String) {
_myLiveData.value = newInfo
}
}
class MyAdapter: RecyclerView.Adapter<RecyclerView.ViewHolder>() {
private var content: String = ""
...
fun updateInfo(newString: String) {
content = newString
notifyDataSetChanged() //or you can implement a DiffUtil.Callback
}
}
Stack Overflow用户
发布于 2022-08-02 02:52:42
在RecyclerView.Adapter中需要重写onCreateViewHolder，传递lifeCycleOwner
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ItemViewHolder {
val lifeCycleOwner = parent.context as LifecycleOwner
val view = LayoutInflater.from(parent.context).inflate(R.layout.item_layout, parent, false)
return ItemViewHolder(view, lifeCycleOwner)
}您的内部类构造函数应该以lifecycleOwner作为param。
inner class ItemViewHolder(view: View, private val lifecycleOwner: LifecycleOwner) : RecyclerView.ViewHolder(view) {然后您就可以正常使用代码了。
mutableLiveData.observe(lifecycleOwner) { /** your logic handle **/ }页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/67024618
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