我正在做database应用程序使用room, mvvm, livedata。我已经用一些数据预填充了它。现在我有两个选择，要么我将在应用程序打开时显示预先填充的数据recyclerview或当我使用搜索时显示它SearchView在recyclerView里面。
The Problem当我搜索特定项目时，itw 在我完成单词时显示该项目，并且当我尝试返回我的 resView 为空或它始终保留在该项目上时。我想找个时间试试realtime就像：当我只输入一个字母表时，它显示所有建议都属于字母表，我只想更新livedata
我有什么尝试？
1-> 我已经尝试过了switchMap与liveData但我必须刷新我的活动才能取回我的列表。
2-> 我尝试过 resView 过滤器，但没有成功，因为我正在使用 livedata 来更新我的 UI，并且定期尝试不使用livedata它仍然不起作用。
3-> 我尝试过常规editText只是尝试一下，但我发现它没有用，因为面临同样的问题，我的主要重点是searchView
回收者查看代码 使用可过滤或忽略可过滤部分根本不是一个好的尝试
class MyAdapter(
private var context: Context,
private var dataList: List<SearchPojo>
) : RecyclerView.Adapter<MyAdapter.BaseViewHolder<*>>(), Filterable {
private var exampleListFull: List<SearchPojo>? = null
init {
exampleListFull = ArrayList(dataList)
}
companion object {
const val SEARCH_TYPE = 1
}
abstract class BaseViewHolder<T>(view: View) : RecyclerView.ViewHolder(view) {
abstract fun bind(t: T)
}
inner class SearchViewHolder(view: View) : BaseViewHolder<SearchPojo>(view) {
private val userID: TextView = view.findViewById(R.id.idSearch)
private val userName: TextView = view.findViewById(R.id.nameSearch)
private val userPos: TextView = view.findViewById(R.id.positionSearch)
override fun bind(t: SearchPojo) {
userID.text = t.id
userName.text = t.userName
userPos.text = t.position
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): BaseViewHolder<*> {
return when (viewType) {
SEARCH_TYPE -> {
val view =
LayoutInflater.from(context).inflate(R.layout.layout_show_data, parent, false)
SearchViewHolder(view)
}
else -> {
throw IllegalAccessException("In valid View Type")
}
}
}
override fun getItemCount(): Int {
return dataList.size
}
override fun onBindViewHolder(holder: BaseViewHolder<*>, position: Int) {
val element = dataList[position]
when (holder) {
is SearchViewHolder -> {
holder.bind(element)
}
}
}
override fun getItemViewType(position: Int): Int {
return when (dataList[position]) {
is SearchPojo -> SEARCH_TYPE
else -> throw IllegalAccessException()
}
}
override fun getFilter(): Filter {
return exampleFilter
}
private var exampleFilter = object : Filter() {
override fun performFiltering(constraint: CharSequence?): FilterResults {
val filteredList = ArrayList<SearchPojo>()
if (constraint == null || constraint.isEmpty()) {
filteredList.addAll(exampleListFull as Iterable<SearchPojo>)
} else {
val filterPattern = constraint.toString().toLowerCase().trim { it <= ' ' }
for (item in exampleListFull!!) {
if (item.userName.toLowerCase().contains(filterPattern)) {
filteredList.add(item)
}
}
}
val results = FilterResults()
results.values = filteredList
return results
}
override fun publishResults(constraint: CharSequence, results: FilterResults) {
dataList.clear()
dataList.addAll(results.values as List<SearchPojo>)
notifyDataSetChanged()
}
}
}
主要活动
class MainActivity : AppCompatActivity() {
lateinit var searchViewModel: SearchViewModel
lateinit var myAdapter: MyAdapter
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
if (!::searchViewModel.isInitialized) {
searchViewModel = ViewModelProviders.of(this)[SearchViewModel::class.java]
searchViewModel.getAll().observe(this, Observer {
myAdapter(it)
})
}
searchItems.addTextChangedListener(object : TextWatcher {
override fun afterTextChanged(s: Editable?) {
}
override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {
}
override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) {
nameFromDb(s.toString())
}
})
}
override fun onCreateOptionsMenu(menu: Menu?): Boolean {
menuInflater.inflate(R.menu.search_item, menu)
val searchItem = menu!!.findItem(R.id.search_menu)
val searchView = searchItem.actionView as SearchView
searchView.setOnQueryTextListener(object : SearchView.OnQueryTextListener {
override fun onQueryTextSubmit(query: String?): Boolean {
return false
}
override fun onQueryTextChange(newText: String?): Boolean {
myAdapter.getFilter().filter(newText)
return true
}
})
return super.onCreateOptionsMenu(menu)
}
override fun onOptionsItemSelected(item: MenuItem?): Boolean {
when (item!!.itemId) {
R.id.refresh -> {
val intent = Intent(this, MainActivity::class.java)
startActivity(intent)
}
}
return true
}
private fun nameFromDb(searchTxt: String) {
searchViewModel = ViewModelProviders.of(this)[SearchViewModel::class.java]
searchViewModel.items.observe(this, object : Observer<List<SearchPojo>> {
override fun onChanged(t: List<SearchPojo>?) {
if (t == null) {
return
}
myAdapter(t)
}
})
searchViewModel.searchIt(searchTxt)
}
private fun myAdapter(t: List<SearchPojo>) {
searchResultResView.apply {
layoutManager = LinearLayoutManager(context)
myAdapter = MyAdapter(this@MainActivity, t)
adapter = myAdapter
}
}
}
视图模型
lass SearchViewModel(application: Application) :
AndroidViewModel(application) {
private val repo: SearchRepo = SearchRepo(application)
private val _searchItem : MutableLiveData<String> = MutableLiveData()
val items : LiveData<List<SearchPojo>> = Transformations.switchMap(_searchItem) { myItems ->
repo.searchItem(myItems)
}
init {
_searchItem.value = ""
}
fun searchIt(items: String) {
_searchItem.value = items
}
fun getAll() = repo.allSearch()
}
存储库
class SearchRepo(application: Application) {
private val searchDao: SearchDao
init {
val db = SearchDb.instance(application)
searchDao = db.searchDao()
}
fun searchItem(id: String): LiveData<List<SearchPojo>> {
return searchDao.searchViaID(id)
}
fun allSearch() : LiveData<List<SearchPojo>> {
return searchDao.allSearch()
}
}
Dao
@Dao
abstract class SearchDao : BaseDao<SearchPojo> {
@Query("Select * from SearchPojo")
abstract fun allSearch(): LiveData<List<SearchPojo>>
@Query("Select * from SearchPojo where userName Like :userNameSearch or LOWER(userName) like LOWER(:userNameSearch)")
abstract fun searchViaID(userNameSearch: String) : LiveData<List<SearchPojo>>
@Insert
abstract override fun insert(searchPojo: SearchPojo)
}
