当在 OnCreateView 中，位图（来自 SharedPreferences 的路径）由 onBindViewHolder 设置时，片段卡住
Fragment stucks when, in OnCreateView, a Bitmap (path from SharedPreferences) is set by onBindViewHolder
我会尝试更具体地说明我的问题。我开始说我已经看到 显示了同样的问题，我想，但我并没有真正理解正确的解决方案。
注意：我在创建新项目步骤
中从模板创建了抽屉activity和所有导航依赖项
最初，我发现当我在 ShowProfileFragment 中尝试更新导航抽屉的 header 时，同样的问题发生了，所以当我放置 if 语句时（见下面的代码) 仅在必要时更新它，问题似乎消失了（因为从抽屉中打开此片段不再执行此操作）。
现在，当我在 ItemListFragment 中添加我所有的 objects，从 SharedPreferences 到传递给适配器（ItemCardsAdapter）的 ArrayList 时一切正常，直到 onBindViewHolder 我在 ImageView 上执行 setImageBitmap。加载位图似乎在浪费时间...
注意：当我在真实设备上 运行 应用程序（我的 phone）时，问题非常突出，这与我电脑上的模拟器中发生的情况不同（此处,一开始就高亮了,当issue是抽屉里头像更新的时候header)
这是我的代码：
MainActivity.kt
import ...
class MainActivity : AppCompatActivity() {
private lateinit var appBarConfiguration: AppBarConfiguration
private var host: NavHostFragment? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val toolbar: Toolbar = findViewById(R.id.toolbar)
setSupportActionBar(toolbar)
host = supportFragmentManager.findFragmentById(R.id.nav_host_fragment) as NavHostFragment?
val drawerLayout: DrawerLayout = findViewById(R.id.drawer_layout)
val navView: NavigationView = findViewById(R.id.nav_view)
var navController = host?.navController //findNavController(R.id.nav_host_fragment)
// Passing each menu ID as a set of Ids because each
// menu should be considered as top level destinations.
// if (savedInstanceState != null) {
// //Restore the fragment's instance
// navController = (supportFragmentManager.getFragment(savedInstanceState, "myFragmentEdit")!! as NavHostFragment?)!!.navController
// }
appBarConfiguration = AppBarConfiguration(setOf(R.id.nav_showprofile, R.id.nav_itemlist), drawerLayout)
setupActionBarWithNavController(navController!!, appBarConfiguration)
navView.setupWithNavController(navController)
/*short info in drawer's header taken from SharedPrefs*/
val sharedPref = getSharedPreferences(getString(R.string.shared_pref_key), Context.MODE_PRIVATE)
val parsedData = sharedPref.getString(getString(R.string.profile_json),"missing data")
if(parsedData != "missing data")
{
val json = Json(JsonConfiguration.Stable)
val obj = json.parse(User.serializer(),parsedData!!)
if(obj.photoPath != "")
navView.getHeaderView(0).header_userpic.setImageBitmap(getCircledBitmap(decodeSampledBitmapFromResource(obj.photoPath,256,256)))
navView.getHeaderView(0).header_username.text = obj.name
navView.getHeaderView(0).header_usermail.text = obj.email
}
else
{
//profile pic path as for as other info are taken from resources here
navView.getHeaderView(0).header_username.text = getString(R.string.user_name)
navView.getHeaderView(0).header_usermail.text = getString(R.string.user_mail)
}
}
// override fun onSaveInstanceState(outState: Bundle) {
// super.onSaveInstanceState(outState)
// supportFragmentManager.putFragment(outState, "myFragmentEdit", host!!)
// }
override fun onSupportNavigateUp(): Boolean {
val navController = findNavController(R.id.nav_host_fragment)
return navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()
}
override fun onBackPressed() {
super.onBackPressed()
}
}
ShowProfileFragment.kt
import ...
class ShowProfileFragment : Fragment() {
companion object {
fun newInstance() = ShowProfileFragment()
}
private lateinit var viewModel: ShowProfileViewModel
@SuppressLint("RestrictedApi")
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val root = inflater.inflate(R.layout.show_profile_fragment, container, false)
viewModel = ViewModelProviders.of(this).get(ShowProfileViewModel::class.java)
/*get User info from SharedPrefs*/
val sharedPref = this.activity!!.getSharedPreferences(getString(R.string.shared_pref_key), Context.MODE_PRIVATE)
val parsedData = sharedPref.getString(getString(R.string.profile_json),"missing data")
if(parsedData != "missing data")
{
val json = Json(JsonConfiguration.Stable)
val obj = json.parse(User.serializer(),parsedData!!)
/*update header info after user clicks save*/
val header = activity!!.findViewById(R.id.nav_view) as NavigationView
header.getHeaderView(0).header_username.text = obj.name
header.getHeaderView(0).header_usermail.text = obj.email
if(obj.photoPath != "")
{
if(arguments?.getString("headerPic") == "update") /*I mean this statement*/
header.getHeaderView(0).header_userpic.setImageBitmap(getCircledBitmap(decodeSampledBitmapFromResource(obj.photoPath,256,256)))
root.photo.setImageBitmap(getCircledBitmap(decodeSampledBitmapFromResource(obj.photoPath,256,256)))
}
viewModel.userKey = obj.userId
root.full_name.text = obj.name
root.nickname.text = obj.nickname
root.email.text = obj.email
root.geographic_area.text = obj.country
//Log.d("kkk","header info from showProfile: name = ${header.getHeaderView(0).header_username.text}")
}
val storageDir = activity!!.getExternalFilesDir(Environment.DIRECTORY_PICTURES)!!
removeIllegalProfilePic(storageDir,sharedPref)
setHasOptionsMenu(true)
return root
}
override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
inflater.inflate(R.menu.edit_profile, menu)
}
override fun onOptionsItemSelected(item: MenuItem): Boolean {
return when(item.itemId){
R.id.editProfileFragment -> {
val bundle = bundleOf("userKey" to viewModel.userKey)
findNavController().navigate(R.id.action_nav_showprofile_to_editProfileFragment, bundle)
true
}
else -> {
super.onOptionsItemSelected(item)
}
}
//return NavigationUI.onNavDestinationSelected(item, view!!.findNavController()) || super.onOptionsItemSelected(item)
}
@SuppressLint("SimpleDateFormat")
private fun removeIllegalProfilePic(root: File, sPrefs: SharedPreferences){
/*check for illegal 0B file, caused of app termination from the camera activity*/
/*and for illegal file generated by any Activity.RESULT_OK caused of app termination from EditProfileActivity*/
val illegalProfilePic = sPrefs.getString(getString(R.string.illegal_profile_pic_key),"saved")
for(f in root.listFiles()!!)
if (f.length() <= 0 || f.absolutePath == illegalProfilePic)
f.delete()
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
viewModel = ViewModelProviders.of(this).get(ShowProfileViewModel::class.java)
// TODO: Use the ViewModel
}
}
ItemListFragment.kt
import ...
class ItemListFragment : Fragment() {
companion object {
fun newInstance() = ItemListFragment()
}
private lateinit var viewModel: ItemListViewModel
//var itemCardsArray= ArrayList<Item>()
lateinit var mAdapter : ItemCardsAdapter
@SuppressLint("RestrictedApi")
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
viewModel = ViewModelProviders.of(this).get(ItemListViewModel::class.java)
val root = inflater.inflate(R.layout.item_list_fragment, container, false)
val viewManagerPortrait = LinearLayoutManager(activity)
val viewManagerLandscape = GridLayoutManager(activity, 3)
/*adapter -> taken from SharedPrefs*/
var itemCardsArray= ArrayList<Item>()
//itemCardsArray.add( Item("path","Teddy Bear","Sweet Bear baby peluche","13.49","Toddler Toys","Turin","20/12/2020") )
val sharedPref = this.activity!!.getSharedPreferences(getString(R.string.shared_pref_key), Context.MODE_PRIVATE)
val itemCount = sharedPref.getInt(getString(R.string.item_count), 0)
if(itemCount == 0)
root.listItems.visibility = View.GONE
else
{
root.emptyAds.visibility = View.GONE
mAdapter = ItemCardsAdapter(itemCardsArray, this)
//viewAdapter.notifyDataSetChanged()
root.listItems.apply {
setHasFixedSize(true)
// use a linear layout manager if portrait, grid one else
layoutManager = if(activity!!.resources.configuration.orientation == Configuration.ORIENTATION_LANDSCAPE)
viewManagerLandscape
else
viewManagerPortrait
// specify an viewAdapter (see also next example)
adapter = mAdapter
//adapter!!.notifyDataSetChanged()
}
for(i in 1..itemCount)
{
val parsedData = sharedPref.getString(getString(R.string.item_json)+i.toString(),"missing data")
if(parsedData != "missing data")
{
val json = Json(JsonConfiguration.Stable)
val obj = json.parse(Item.serializer(),parsedData!!)
itemCardsArray.add(i-1, obj)
mAdapter.notifyItemInserted(i-1)
}
}
}
root.fab_addItem.setOnClickListener {
Snackbar.make(it, "Creating new advertisement...", Snackbar.LENGTH_LONG)
.setAction("Action", null).show()
findNavController().navigate(R.id.action_nav_itemlist_to_itemEditFragment)
}
return root
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
viewModel = ViewModelProviders.of(this).get(ItemListViewModel::class.java)
// TODO: Use the ViewModel
}
}
ItemCardsAdapter.kt
import ...
class ItemCardsAdapter(private val myDataset: ArrayList<Item>, private val f: Fragment) : RecyclerView.Adapter<ItemCardsAdapter.MyViewHolder>() {
class MyViewHolder(viewItem: View) : RecyclerView.ViewHolder(viewItem){
val itemphoto = viewItem.itemphoto
val itemtitle = viewItem.title
val itemprice = viewItem.itemprice
val itemlocation = viewItem.itemlocation
val editpencil = viewItem.editCard
}
// Create new views (invoked by the layout manager)
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
// create a new view
val viewItem = LayoutInflater.from(parent.context).inflate(R.layout.item_card, parent, false)
// set the view's size, margins, paddings and layout parameters
return MyViewHolder(viewItem)
}
// Replace the contents of a view (invoked by the layout manager)
override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
holder.itemtitle.text = myDataset[position].title
holder.itemprice.text = myDataset[position].price
holder.itemlocation.text = myDataset[position].location
if(myDataset[position].photoPath != "") /*Here it stucks on load !?*/
holder.itemphoto.setImageBitmap(decodeSampledBitmapFromResource(myDataset[position].photoPath,256,256))
//holder.View.startAnimation(AnimationUtils.loadLayoutAnimation(this,R.anim.layout_animation))
val bundle = bundleOf("itemAdKey" to myDataset[position].adId)
holder.editpencil.setOnClickListener {
bundle.putString("nav", "editCard")
f.findNavController().navigate(R.id.action_nav_itemlist_to_itemEditFragment, bundle)
}
holder.itemView.setOnClickListener {
f.findNavController().navigate(R.id.action_nav_itemlist_to_nav_itemdetails, bundle)
}
}
// Return the size of your dataset (invoked by the layout manager)
override fun getItemCount() = myDataset.size
}
我按照官方文档找到了解决方案：
https://developer.android.com/topic/performance/graphics
建议使用此外部库来解决此类内存缓存问题：Glide
所以，我改变了，例如，这个
ItemCardsAdapter.kt
holder.itemphoto.setImageBitmap(decodeSampledBitmapFromResource(myDataset[position].photoPath,256,256))
有了这个
Glide.with(f.activity!!).load(myDataset[position].photoPath).into(holder.itemphoto)
我会尝试更具体地说明我的问题。我开始说我已经看到
注意：我在创建新项目步骤
中从模板创建了抽屉activity和所有导航依赖项最初，我发现当我在 ShowProfileFragment 中尝试更新导航抽屉的 header 时，同样的问题发生了，所以当我放置 if 语句时（见下面的代码) 仅在必要时更新它，问题似乎消失了（因为从抽屉中打开此片段不再执行此操作）。
现在，当我在 ItemListFragment 中添加我所有的 objects，从 SharedPreferences 到传递给适配器（ItemCardsAdapter）的 ArrayList 时一切正常，直到 onBindViewHolder 我在 ImageView 上执行 setImageBitmap。加载位图似乎在浪费时间...
注意：当我在真实设备上 运行 应用程序（我的 phone）时，问题非常突出，这与我电脑上的模拟器中发生的情况不同（此处,一开始就高亮了,当issue是抽屉里头像更新的时候header)
这是我的代码：
MainActivity.kt
import ...
class MainActivity : AppCompatActivity() {
private lateinit var appBarConfiguration: AppBarConfiguration
private var host: NavHostFragment? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val toolbar: Toolbar = findViewById(R.id.toolbar)
setSupportActionBar(toolbar)
host = supportFragmentManager.findFragmentById(R.id.nav_host_fragment) as NavHostFragment?
val drawerLayout: DrawerLayout = findViewById(R.id.drawer_layout)
val navView: NavigationView = findViewById(R.id.nav_view)
var navController = host?.navController //findNavController(R.id.nav_host_fragment)
// Passing each menu ID as a set of Ids because each
// menu should be considered as top level destinations.
// if (savedInstanceState != null) {
// //Restore the fragment's instance
// navController = (supportFragmentManager.getFragment(savedInstanceState, "myFragmentEdit")!! as NavHostFragment?)!!.navController
// }
appBarConfiguration = AppBarConfiguration(setOf(R.id.nav_showprofile, R.id.nav_itemlist), drawerLayout)
setupActionBarWithNavController(navController!!, appBarConfiguration)
navView.setupWithNavController(navController)
/*short info in drawer's header taken from SharedPrefs*/
val sharedPref = getSharedPreferences(getString(R.string.shared_pref_key), Context.MODE_PRIVATE)
val parsedData = sharedPref.getString(getString(R.string.profile_json),"missing data")
if(parsedData != "missing data")
{
val json = Json(JsonConfiguration.Stable)
val obj = json.parse(User.serializer(),parsedData!!)
if(obj.photoPath != "")
navView.getHeaderView(0).header_userpic.setImageBitmap(getCircledBitmap(decodeSampledBitmapFromResource(obj.photoPath,256,256)))
navView.getHeaderView(0).header_username.text = obj.name
navView.getHeaderView(0).header_usermail.text = obj.email
}
else
{
//profile pic path as for as other info are taken from resources here
navView.getHeaderView(0).header_username.text = getString(R.string.user_name)
navView.getHeaderView(0).header_usermail.text = getString(R.string.user_mail)
}
}
// override fun onSaveInstanceState(outState: Bundle) {
// super.onSaveInstanceState(outState)
// supportFragmentManager.putFragment(outState, "myFragmentEdit", host!!)
// }
override fun onSupportNavigateUp(): Boolean {
val navController = findNavController(R.id.nav_host_fragment)
return navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()
}
override fun onBackPressed() {
super.onBackPressed()
}
}
ShowProfileFragment.kt
import ...
class ShowProfileFragment : Fragment() {
companion object {
fun newInstance() = ShowProfileFragment()
}
private lateinit var viewModel: ShowProfileViewModel
@SuppressLint("RestrictedApi")
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val root = inflater.inflate(R.layout.show_profile_fragment, container, false)
viewModel = ViewModelProviders.of(this).get(ShowProfileViewModel::class.java)
/*get User info from SharedPrefs*/
val sharedPref = this.activity!!.getSharedPreferences(getString(R.string.shared_pref_key), Context.MODE_PRIVATE)
val parsedData = sharedPref.getString(getString(R.string.profile_json),"missing data")
if(parsedData != "missing data")
{
val json = Json(JsonConfiguration.Stable)
val obj = json.parse(User.serializer(),parsedData!!)
/*update header info after user clicks save*/
val header = activity!!.findViewById(R.id.nav_view) as NavigationView
header.getHeaderView(0).header_username.text = obj.name
header.getHeaderView(0).header_usermail.text = obj.email
if(obj.photoPath != "")
{
if(arguments?.getString("headerPic") == "update") /*I mean this statement*/
header.getHeaderView(0).header_userpic.setImageBitmap(getCircledBitmap(decodeSampledBitmapFromResource(obj.photoPath,256,256)))
root.photo.setImageBitmap(getCircledBitmap(decodeSampledBitmapFromResource(obj.photoPath,256,256)))
}
viewModel.userKey = obj.userId
root.full_name.text = obj.name
root.nickname.text = obj.nickname
root.email.text = obj.email
root.geographic_area.text = obj.country
//Log.d("kkk","header info from showProfile: name = ${header.getHeaderView(0).header_username.text}")
}
val storageDir = activity!!.getExternalFilesDir(Environment.DIRECTORY_PICTURES)!!
removeIllegalProfilePic(storageDir,sharedPref)
setHasOptionsMenu(true)
return root
}
override fun onCreateOptionsMenu(menu: Menu, inflater: MenuInflater) {
inflater.inflate(R.menu.edit_profile, menu)
}
override fun onOptionsItemSelected(item: MenuItem): Boolean {
return when(item.itemId){
R.id.editProfileFragment -> {
val bundle = bundleOf("userKey" to viewModel.userKey)
findNavController().navigate(R.id.action_nav_showprofile_to_editProfileFragment, bundle)
true
}
else -> {
super.onOptionsItemSelected(item)
}
}
//return NavigationUI.onNavDestinationSelected(item, view!!.findNavController()) || super.onOptionsItemSelected(item)
}
@SuppressLint("SimpleDateFormat")
private fun removeIllegalProfilePic(root: File, sPrefs: SharedPreferences){
/*check for illegal 0B file, caused of app termination from the camera activity*/
/*and for illegal file generated by any Activity.RESULT_OK caused of app termination from EditProfileActivity*/
val illegalProfilePic = sPrefs.getString(getString(R.string.illegal_profile_pic_key),"saved")
for(f in root.listFiles()!!)
if (f.length() <= 0 || f.absolutePath == illegalProfilePic)
f.delete()
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
viewModel = ViewModelProviders.of(this).get(ShowProfileViewModel::class.java)
// TODO: Use the ViewModel
}
}
ItemListFragment.kt
import ...
class ItemListFragment : Fragment() {
companion object {
fun newInstance() = ItemListFragment()
}
private lateinit var viewModel: ItemListViewModel
//var itemCardsArray= ArrayList<Item>()
lateinit var mAdapter : ItemCardsAdapter
@SuppressLint("RestrictedApi")
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
viewModel = ViewModelProviders.of(this).get(ItemListViewModel::class.java)
val root = inflater.inflate(R.layout.item_list_fragment, container, false)
val viewManagerPortrait = LinearLayoutManager(activity)
val viewManagerLandscape = GridLayoutManager(activity, 3)
/*adapter -> taken from SharedPrefs*/
var itemCardsArray= ArrayList<Item>()
//itemCardsArray.add( Item("path","Teddy Bear","Sweet Bear baby peluche","13.49","Toddler Toys","Turin","20/12/2020") )
val sharedPref = this.activity!!.getSharedPreferences(getString(R.string.shared_pref_key), Context.MODE_PRIVATE)
val itemCount = sharedPref.getInt(getString(R.string.item_count), 0)
if(itemCount == 0)
root.listItems.visibility = View.GONE
else
{
root.emptyAds.visibility = View.GONE
mAdapter = ItemCardsAdapter(itemCardsArray, this)
//viewAdapter.notifyDataSetChanged()
root.listItems.apply {
setHasFixedSize(true)
// use a linear layout manager if portrait, grid one else
layoutManager = if(activity!!.resources.configuration.orientation == Configuration.ORIENTATION_LANDSCAPE)
viewManagerLandscape
else
viewManagerPortrait
// specify an viewAdapter (see also next example)
adapter = mAdapter
//adapter!!.notifyDataSetChanged()
}
for(i in 1..itemCount)
{
val parsedData = sharedPref.getString(getString(R.string.item_json)+i.toString(),"missing data")
if(parsedData != "missing data")
{
val json = Json(JsonConfiguration.Stable)
val obj = json.parse(Item.serializer(),parsedData!!)
itemCardsArray.add(i-1, obj)
mAdapter.notifyItemInserted(i-1)
}
}
}
root.fab_addItem.setOnClickListener {
Snackbar.make(it, "Creating new advertisement...", Snackbar.LENGTH_LONG)
.setAction("Action", null).show()
findNavController().navigate(R.id.action_nav_itemlist_to_itemEditFragment)
}
return root
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
viewModel = ViewModelProviders.of(this).get(ItemListViewModel::class.java)
// TODO: Use the ViewModel
}
}
ItemCardsAdapter.kt
import ...
class ItemCardsAdapter(private val myDataset: ArrayList<Item>, private val f: Fragment) : RecyclerView.Adapter<ItemCardsAdapter.MyViewHolder>() {
class MyViewHolder(viewItem: View) : RecyclerView.ViewHolder(viewItem){
val itemphoto = viewItem.itemphoto
val itemtitle = viewItem.title
val itemprice = viewItem.itemprice
val itemlocation = viewItem.itemlocation
val editpencil = viewItem.editCard
}
// Create new views (invoked by the layout manager)
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): MyViewHolder {
// create a new view
val viewItem = LayoutInflater.from(parent.context).inflate(R.layout.item_card, parent, false)
// set the view's size, margins, paddings and layout parameters
return MyViewHolder(viewItem)
}
// Replace the contents of a view (invoked by the layout manager)
override fun onBindViewHolder(holder: MyViewHolder, position: Int) {
holder.itemtitle.text = myDataset[position].title
holder.itemprice.text = myDataset[position].price
holder.itemlocation.text = myDataset[position].location
if(myDataset[position].photoPath != "") /*Here it stucks on load !?*/
holder.itemphoto.setImageBitmap(decodeSampledBitmapFromResource(myDataset[position].photoPath,256,256))
//holder.View.startAnimation(AnimationUtils.loadLayoutAnimation(this,R.anim.layout_animation))
val bundle = bundleOf("itemAdKey" to myDataset[position].adId)
holder.editpencil.setOnClickListener {
bundle.putString("nav", "editCard")
f.findNavController().navigate(R.id.action_nav_itemlist_to_itemEditFragment, bundle)
}
holder.itemView.setOnClickListener {
f.findNavController().navigate(R.id.action_nav_itemlist_to_nav_itemdetails, bundle)
}
}
// Return the size of your dataset (invoked by the layout manager)
override fun getItemCount() = myDataset.size
}
我按照官方文档找到了解决方案：
https://developer.android.com/topic/performance/graphics
建议使用此外部库来解决此类内存缓存问题：Glide
所以，我改变了，例如，这个
ItemCardsAdapter.kt
holder.itemphoto.setImageBitmap(decodeSampledBitmapFromResource(myDataset[position].photoPath,256,256))
有了这个
Glide.with(f.activity!!).load(myDataset[position].photoPath).into(holder.itemphoto)