问题描述
我正在使用recyclerView来显示设备中安装的应用程序列表...。请参见下图
image 1 desc->在此，我使用弹出菜单过滤已安装和系统的应用程序
image 2 desc->在此，我表明，我使用imageView找出已安装的程序或系统应用程序...这些由Play商店和电话图标分别指示。
问题 ......排序工作正常，我想过滤列表，并可以在该列表上进行排序
我设法借助适配器类中的布尔值和函数将filteredList发送到适配器，适配器类将新列表分配给原始列表，但是排序在那里不起作用
此外，我还使用了滑动操作进行删除，如果我发送新列表... onSwiped方法不会获得新的过滤位置....因为它拥有原始列表适配器位置
MainActivity.kt
class MainActivity : AppCompatActivity() {
lateinit var adapter: Adapter // create adapter instance
lateinit var applicationList: MutableList<AppData>
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
applicationList = getApps(installedApps()) // initialize applicationList variable
recyclerView.layoutManager = linearlayoutmanager(this)
adapter = Adapter(applicationList) // initialize adapter variable
recyclerView.adapter = adapter // pass adapter to recyclerView
updateNumberOfApps()
sortList()
filterList()
}
private fun sortList() {
Sort_List.setonClickListener {
val popUp = PopupMenu(this,Sort_List)
popUp.menuInflater.inflate(R.menu.sort_menu,popUp.menu)
popUp.setonMenuItemClickListener { myItem ->
when (myItem.itemId) {
R.id.Name_ASC -> {
applicationList.sortBy { it.name }
adapter.notifyDataSetChanged()
scrollToTop()
}
}
true
}
popUp.show()
}
}
private fun filterList() {
Filter_List.setonClickListener {
val popUp = PopupMenu(this,Filter_List)
popUp.menuInflater.inflate(R.menu.filter_menu,popUp.menu)
popUp.setonMenuItemClickListener { myItem ->
when (myItem.itemId) {
R.id.Installed_Apps -> {
applicationList.all { it.category }
adapter.notifyDataSetChanged()
updateNumberOfApps()
scrollToTop()
}
R.id.System_Apps -> {
// PROBLEM IS HERE>>>I WANT FILTER AND SORTING WORKING TOGETHER
applicationList.sortedBy { it.category }
adapter.notifyDataSetChanged()
updateNumberOfApps()
// here I also manage to send list and assign to adapter like
// val list = applicationList.filter { it.category }
// adapter.update(list)
}
}
true
}
popUp.show()
}
}
private fun getApps(List: MutableList<ResolveInfo>): MutableList<AppData> {
// here I get all apps and return list
// In this,I also get Boolean value(named category),which return true on system app and false on the installed app
}
}
}
Adapter.kt
class Adapter(private var listofApps: MutableList<AppData>) :
RecyclerView.Adapter<Adapter.ViewHolder>() {
class ViewHolder(appView: View) : RecyclerView.ViewHolder(appView) {
// call elements from list_apps.xml
val icon: ImageView = appView.App_icon
val name: TextView = appView.App_name
val size: TextView = appView.App_size
}
override fun onCreateViewHolder(parent: ViewGroup,viewType: Int): ViewHolder {
val view = LayoutInflater.from(parent.context).inflate(
R.layout.list_apps,parent,false
)
return ViewHolder(view)
}
override fun getItemCount() = listofApps.size
override fun onBindViewHolder(holder: ViewHolder,position: Int) {
val currentItem = listofApps[position]
holder.icon.setimageDrawable(currentItem.icon)
holder.name.text = currentItem.name
holder.size.text = currentItem.size
}
}
// here I declare function which get list from filter method and assign new list to original list
fun update(newList: MutableList<AppData>){
listofApps = newList
notifyDataSetChanged()
}
}
解决方法
问题是applicationList.all { it.category }不过滤列表。它检查列表并返回true，如果it.category的所有项目都获得true，否则返回false。您应该改用filter。
applicationList = applicationList.filter { it.category }
请注意，filter不是就地操作。因此，您应该将其结果设置为applicationList。
编辑
您应始终保留当前显示列表的状态，并根据这些状态进行填充。我通过添加两个如下所示的布尔值更改了您的代码：
class MainActivity : AppCompatActivity() {
lateinit var adapter: Adapter // create adapter instance
lateinit var applicationList: MutableList<AppData>
private val showingApplicationList: MutableList<AppData> = mutableListOf()
private var isSortedDesc = false
private var isShowingSystemApps = false
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
applicationList = getApps(installedApps()) // initialize applicationList variable
recyclerView.layoutManager = LinearLayoutManager(this)
adapter = Adapter(showingApplicationList) // initialize adapter variable
recyclerView.adapter = adapter // pass adapter to recyclerView
updateNumberOfApps()
sortList()
filterList()
arrangeAppList()
adapter.update(showingApplicationList)
}
private fun sortList() {
Sort_List.setOnClickListener {
val popUp = PopupMenu(this,Sort_List)
popUp.menuInflater.inflate(R.menu.sort_menu,popUp.menu)
popUp.setOnMenuItemClickListener { myItem ->
when (myItem.itemId) {
R.id.Name_ASC -> {
isSortedDesc = false
arrangeAppList()
adapter.update(showingApplicationList)
scrollToTop()
}
R.id.Name_DESC -> {
isSortedDesc = true
arrangeAppList()
adapter.update(showingApplicationList)
scrollToTop()
}
}
true
}
popUp.show()
}
}
private fun filterList() {
Filter_List.setOnClickListener {
val popUp = PopupMenu(this,Filter_List)
popUp.menuInflater.inflate(R.menu.filter_menu,popUp.menu)
popUp.setOnMenuItemClickListener { myItem ->
when (myItem.itemId) {
R.id.Installed_Apps -> {
isShowingSystemApps = false
arrangeAppList()
adapter.update(showingApplicationList)
scrollToTop()
updateNumberOfApps()
}
R.id.System_Apps -> {
isShowingSystemApps = true
arrangeAppList()
adapter.update(showingApplicationList)
scrollToTop()
updateNumberOfApps()
}
}
true
}
popUp.show()
}
}
private fun arrangeAppList() {
showingApplicationList.clear()
showingApplicationList.addAll(
applicationList.filter { it.category == isShowingSystemApps }
)
if (isSortedDesc) {
showingApplicationList.sortByDescending { it.name }
} else {
showingApplicationList.sortBy { it.name }
}
}
private fun getApps(List: MutableList<ResolveInfo>): MutableList<AppData> {
// here I get all apps and return list
// In this,I also get Boolean value(named category),which return true on system app and false on the installed app
}
}