使用适配器从RecyclerView筛选searchView

Question

适配器类

class AppListAdapter(private val context: Context, initialChecked: ArrayList<String> = arrayListOf()) :  RecyclerView.Adapter<AppListAdapter.AppViewHolder>() {
public val appList = arrayListOf<ApplicationInfo>()
private val checkedAppList = arrayListOf<Boolean>()
private val packageManager: PackageManager = context.packageManager
init {
context.packageManager.getInstalledApplications(PackageManager.GET_META_DATA).sortedBy { it.loadLabel(packageManager).toString() }.forEach { info ->
if (info.packageName != context.packageName) {
if (info.flags and ApplicationInfo.FLAG_SYSTEM == 0) {
appList.add(info)
checkedAppList.add(initialChecked.contains(info.packageName))
}
}
}
}
inner class AppViewHolder(private val item: ItemAppBinding) : RecyclerView.ViewHolder(item.root) {
fun bind(data: ApplicationInfo, position: Int) {
item.txApp.text = data.loadLabel(packageManager)
item.imgIcon.setImageDrawable(data.loadIcon(packageManager))
item.cbApp.isChecked = checkedAppList[position]
item.cbApp.setOnCheckedChangeListener { _, checked ->
checkedAppList[position] = checked
}
}
}
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): AppViewHolder {
return AppViewHolder(ItemAppBinding.inflate(LayoutInflater.from(context), parent, false))
}
override fun onBindViewHolder(holder: AppViewHolder, position: Int) {
holder.bind(appList[position], position)
}
override fun getItemCount(): Int {
return appList.size
}

关于主活动

binding.searchView2.setOnQueryTextListener(object : SearchView.OnQueryTextListener{
override fun onQueryTextSubmit(query: String?): Boolean {
binding.searchView2.clearFocus()
// how to write code filtered by query?
return false
}
override fun onQueryTextChange(newText: String?): Boolean {
// how to write code filtered by newText?
return false
}
})

Answer 1

我相信你想用"ApplicationInfo.txApp"；，所以我会为它编写代码。
首先，你需要你的适配器类来扩展Filterable，如下所示，并添加一个列表来容纳所有项目：

class AppListAdapter(private val context: Context, initialChecked: ArrayList<String> = arrayListOf()) :  RecyclerView.Adapter<AppListAdapter.AppViewHolder>(), Filterable {
public val appList = arrayListOf<ApplicationInfo>()
public val appListFull = ArrayList<ApplicationInfo>(appList)
// This full list because of when you delete all the typing to searchView
// so it will get back to that full form.

然后覆盖它的功能并编写自己的过滤器以工作，将此代码粘贴到您的适配器：

override fun getFilter(): Filter {
return exampleFilter
}
private val exampleFilter = object : Filter() {
override fun performFiltering(constraint: CharSequence?): FilterResults? {
val filteredList: ArrayList<ApplicationInfo> = ArrayList()
if (constraint == null || constraint.isEmpty()) {
// when searchview is empty
filteredList.addAll(appListFull)
} else {
// when you type something
// it also uses Locale in case capital letters different.
val filterPattern = constraint.toString().lowercase(Locale.getDefault()).trim()
for (item in appListFull) {
val txApp = item.txApp
if (txApp.lowercase(Locale.getDefault()).contains(filterPattern)) {
filteredList.add(item)
}
}
}
val results = FilterResults()
results.values = filteredList
return results
}
@SuppressLint("NotifyDataSetChanged") @Suppress("UNCHECKED_CAST")
override fun publishResults(constraint: CharSequence?, results: FilterResults?) {
appList.clear()
appList.addAll(results!!.values as ArrayList<ApplicationInfo>)
notifyDataSetChanged()
}
}

最后在您的搜索视图中调用这个过滤方法：

binding.searchView2.setOnQueryTextListener(object : SearchView.OnQueryTextListener{
override fun onQueryTextSubmit(query: String?): Boolean {
yourAdapter.filter.filter(query)
yourAdapter.notifyDataSetChanged()
binding.searchView2.clearFocus()
return false
}
override fun onQueryTextChange(newText: String?): Boolean {
yourAdapter.filter.filter(newText)
yourAdapter.notifyDataSetChanged()
return false
}
})

如果不让我知道这个问题的话，我正在使用类似的东西。