[英]Change RecyclerView Layout (from Linear to Grid and reverse) when rotate device automatically
我有 4 个不同的“卡片列表” 、“卡片杂志” 、 “标题”和“网格” ，每个视图持有者都相关，请在此处查看我的其他问题。
现在我试图在设备旋转时自动更改布局，因此当方向为纵向时，布局为 LinearLayout“卡片布局”，当方向更改为横向时，布局将为 GridLayout，我还有一个changeAndSaveLayout方法让用户选择选项菜单中的每个布局之间
然后我使用DataStore和Flow将布局保存在ViewModel中，
当我旋转设备时，RecyclerView 和列表消失了，我看到空屏幕，当我回到纵向时，列表又回来了，它又回到了默认布局“cardLayout”
我在更改布局后尝试了多种方法，例如notifyDataSetChanged并处理onConfigurationChanged方法中的更改，但所有这些方法都失败了
DataStore class 代码saveRecyclerViewLayout和readRecyclerViewLayout
private val Context.dataStore by preferencesDataStore("user_preferences")
private const val TAG = "DataStoreRepository"
@ActivityRetainedScoped
class DataStoreRepository @Inject constructor(@ApplicationContext private val context: Context) {
suspend fun saveRecyclerViewLayout(
recyclerViewLayout: String,
) {
datastore.edit { preferences ->
preferences[PreferencesKeys.RECYCLER_VIEW_LAYOUT_KEY] = recyclerViewLayout
}
}
val readRecyclerViewLayout:
Flow<String> = datastore.data.catch { ex ->
if (ex is IOException) {
ex.message?.let { Log.e(TAG, it) }
emit(emptyPreferences())
} else {
throw ex
}
}.map { preferences ->
val recyclerViewLayout: String =
preferences[PreferencesKeys.RECYCLER_VIEW_LAYOUT_KEY] ?: "cardLayout"
recyclerViewLayout
}
}
我在ViewModel中使用它，如下所示
@HiltViewModel
class PostViewModel @Inject constructor(
private val mainRepository: MainRepository,
private val dataStoreRepository: DataStoreRepository,
application: Application
) :
AndroidViewModel(application) {
val recyclerViewLayout = dataStoreRepository.readRecyclerViewLayout.asLiveData()
fun saveRecyclerViewLayout(layout: String) {
viewModelScope.launch {
dataStoreRepository.saveRecyclerViewLayout(layout)
}
}
}
邮政适配器 Class
class PostAdapter(
private val titleAndGridLayout: TitleAndGridLayout,
) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {
var viewType = 0
private val differCallback = object : DiffUtil.ItemCallback<Item>() {
override fun areItemsTheSame(oldItem: Item, newItem: Item): Boolean {
return (oldItem.id == newItem.id)
}
override fun areContentsTheSame(oldItem: Item, newItem: Item): Boolean {
return (oldItem == newItem)
}
}
val differ = AsyncListDiffer(this, differCallback)
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
return when (this.viewType) {
CARD -> {
fromCardViewHolder(parent)
}
CARD_MAGAZINE -> {
fromCardMagazineViewHolder(parent)
}
TITLE -> {
fromTitleViewHolder(parent)
}
else -> {
fromGridViewHolder(parent)
}
}
}
override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
val item: Item = differ.currentList[position]
when (this.viewType) {
CARD -> if (holder is CardViewHolder) {
holder.bind(item)
}
CARD_MAGAZINE -> if (holder is CardMagazineViewHolder) {
holder.bind(item)
}
TITLE -> if (holder is TitleViewHolder) {
holder.bind(item)
if (position == itemCount - 1)
titleAndGridLayout.tellFragmentToGetItems()
}
GRID -> if (holder is GridViewHolder) {
holder.bind(item)
if (position == itemCount - 1)
titleAndGridLayout.tellFragmentToGetItems()
}
}
}
override fun getItemCount(): Int {
return differ.currentList.size
}
override fun getItemId(position: Int): Long {
return position.toLong()
}
class CardViewHolder(private val cardLayoutBinding: CardLayoutBinding) :
RecyclerView.ViewHolder(cardLayoutBinding.root) {
fun bind(item: Item) {
val document = Jsoup.parse(item.content)
val elements = document.select("img")
var date: Date? = Date()
val format = SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ", Locale.getDefault())
cardLayoutBinding.postTitle.text = item.title
try {
Glide.with(cardLayoutBinding.root).load(elements[0].attr("src"))
.transition(DrawableTransitionOptions.withCrossFade(600))
.placeholder(R.drawable.loading_animation)
.error(R.drawable.no_image)
.into(cardLayoutBinding.postImage)
} catch (e: IndexOutOfBoundsException) {
cardLayoutBinding.postImage.setImageResource(R.drawable.no_image)
}
cardLayoutBinding.postDescription.text = document.text()
try {
date = format.parse(item.published)
} catch (e: ParseException) {
e.printStackTrace()
}
val prettyTime = PrettyTime()
cardLayoutBinding.postDate.text = prettyTime.format(date)
}
}
class CardMagazineViewHolder(private val cardMagazineBinding: CardMagazineBinding) :
RecyclerView.ViewHolder(cardMagazineBinding.root) {
fun bind(item: Item) {
val document = Jsoup.parse(item.content)
val elements = document.select("img")
var date: Date? = Date()
val format = SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ", Locale.getDefault())
cardMagazineBinding.postTitle.text = item.title
try {
Glide.with(itemView.context).load(elements[0].attr("src"))
.transition(DrawableTransitionOptions.withCrossFade(600))
.placeholder(R.drawable.loading_animation)
.error(R.drawable.no_image)
.into(cardMagazineBinding.postImage)
} catch (e: IndexOutOfBoundsException) {
cardMagazineBinding.postImage.setImageResource(R.drawable.no_image)
}
try {
date = format.parse(item.published)
} catch (e: ParseException) {
e.printStackTrace()
}
val prettyTime = PrettyTime()
cardMagazineBinding.postDate.text = prettyTime.format(date)
}
}
class TitleViewHolder(private val binding: TitleLayoutBinding) :
RecyclerView.ViewHolder(binding.root) {
fun bind(item: Item) {
val document = Jsoup.parse(item.content)
val elements = document.select("img")
binding.postTitle.text = item.title
try {
Glide.with(itemView.context).load(elements[0].attr("src"))
.transition(DrawableTransitionOptions.withCrossFade(600))
.placeholder(R.drawable.loading_animation)
.error(R.drawable.no_image)
.into(binding.postImage)
} catch (e: IndexOutOfBoundsException) {
binding.postImage.setImageResource(R.drawable.no_image)
}
}
}
class GridViewHolder constructor(private val binding: GridLayoutBinding) :
RecyclerView.ViewHolder(binding.root) {
fun bind(item: Item) {
val document = Jsoup.parse(item.content)
val elements = document.select("img")
binding.postTitle.text = item.title
try {
Glide.with(itemView.context).load(elements[0].attr("src"))
.transition(DrawableTransitionOptions.withCrossFade(600))
.placeholder(R.drawable.loading_animation)
.error(R.drawable.no_image)
.into(binding.postImage)
} catch (e: IndexOutOfBoundsException) {
binding.postImage.setImageResource(R.drawable.no_image)
}
}
}
companion object {
private const val CARD = 0
private const val CARD_MAGAZINE = 1
private const val TITLE = 2
private const val GRID = 3
private const val TAG = "POST_ADAPTER"
fun fromCardViewHolder(parent: ViewGroup): CardViewHolder {
val cardLayoutBinding: CardLayoutBinding =
CardLayoutBinding.inflate(LayoutInflater.from(parent.context), parent, false)
return CardViewHolder(cardLayoutBinding)
}
fun fromCardMagazineViewHolder(parent: ViewGroup): CardMagazineViewHolder {
val cardMagazineBinding: CardMagazineBinding =
CardMagazineBinding.inflate(
LayoutInflater.from(parent.context),
parent,
false
)
return CardMagazineViewHolder(cardMagazineBinding)
}
fun fromTitleViewHolder(parent: ViewGroup): TitleViewHolder {
val titleLayoutBinding: TitleLayoutBinding =
TitleLayoutBinding.inflate(LayoutInflater.from(parent.context), parent, false)
return TitleViewHolder(titleLayoutBinding)
}
fun fromGridViewHolder(
parent: ViewGroup
): GridViewHolder {
val gridLayoutBinding: GridLayoutBinding =
GridLayoutBinding.inflate(LayoutInflater.from(parent.context), parent, false)
return GridViewHolder(gridLayoutBinding)
}
}
init {
setHasStableIds(true)
}
}
最后是HomeFragment
@AndroidEntryPoint
class HomeFragment : Fragment(), TitleAndGridLayout, MenuProvider {
private var _binding: FragmentHomeBinding? = null
private val binding get() = _binding!!
private var itemArrayList = arrayListOf<Item>()
private var searchItemList = arrayListOf<Item>()
private val postViewModel: PostViewModel by viewModels()
private var linearLayoutManager: LinearLayoutManager? = null
private val titleLayoutManager: GridLayoutManager by lazy {
GridLayoutManager(requireContext(), 2)
}
private val gridLayoutManager: GridLayoutManager by lazy {
GridLayoutManager(requireContext(), 3)
}
private var menuHost: MenuHost? = null
private lateinit var networkListener: NetworkListener
private lateinit var adapter:PostAdapter
private var isScrolling = false
var currentItems = 0
var totalItems: Int = 0
var scrollOutItems: Int = 0
private var postsAPiFlag = false
private val recyclerStateKey = "recycler_state"
private val mBundleRecyclerViewState by lazy { Bundle() }
private var keyword: String? = null
private var orientation: Int? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
postViewModel.finalURL.value = "$BASE_URL?key=$API_KEY"
networkListener = NetworkListener()
}
// This property is only valid between onCreateView and
// onDestroyView.
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View {
adapter = PostAdapter(this)
orientation = resources.configuration.orientation
_binding = FragmentHomeBinding.inflate(inflater, container, false)
menuHost = requireActivity()
menuHost?.addMenuProvider(this, viewLifecycleOwner, Lifecycle.State.CREATED)
postViewModel.recyclerViewLayout.observe(viewLifecycleOwner) { layout ->
linearLayoutManager = LinearLayoutManager(context, LinearLayoutManager.VERTICAL, false)
Log.w(TAG, "getSavedLayout called")
Log.w(TAG, "getSavedLayout: orientation ${orientation.toString()}", )
if (orientation == Configuration.ORIENTATION_PORTRAIT) {
when (layout) {
"cardLayout" -> {
//
adapter.viewType = 0
binding.apply {
homeRecyclerView.layoutManager = linearLayoutManager
homeRecyclerView.adapter = adapter
}
}
"cardMagazineLayout" -> {
// binding.loadMoreBtn.visibility = View.VISIBLE
binding.homeRecyclerView.layoutManager = linearLayoutManager
adapter.viewType = 1
binding.homeRecyclerView.adapter = adapter
}
}
} else if (orientation == Configuration.ORIENTATION_LANDSCAPE) {
when (layout) {
"titleLayout" -> {
// binding.loadMoreBtn.visibility = View.GONE
binding.homeRecyclerView.layoutManager = titleLayoutManager
adapter.viewType = 2
binding.homeRecyclerView.adapter = adapter
}
"gridLayout" -> {
binding.homeRecyclerView.layoutManager = gridLayoutManager
adapter.viewType = 3
binding.homeRecyclerView.adapter = adapter
}
}
}
override fun onMenuItemSelected(menuItem: MenuItem): Boolean {
return if (menuItem.itemId == R.id.change_layout) {
changeAndSaveLayout()
true
} else false
}
private fun changeAndSaveLayout() {
// Log.w(TAG, "changeAndSaveLayout: called")
val builder = AlertDialog.Builder(requireContext())
builder.setTitle(getString(R.string.choose_layout))
val recyclerViewPortraitLayout =
resources.getStringArray(R.array.RecyclerViewPortraitLayout)
val recyclerViewLandscapeLayout =
resources.getStringArray(R.array.RecyclerViewLandscapeLayout)
// SharedPreferences.Editor editor = sharedPreferences.edit();
Log.d(TAG, "changeAndSaveLayout: ${orientation.toString()}")
if (orientation == 1) {
builder.setItems(
recyclerViewPortraitLayout
) { _: DialogInterface?, index: Int ->
try {
when (index) {
0 -> {
adapter.viewType = 0
binding.homeRecyclerView.layoutManager = linearLayoutManager
binding.homeRecyclerView.adapter = adapter
postViewModel.saveRecyclerViewLayout("cardLayout")
}
1 -> {
adapter.viewType = 1
binding.homeRecyclerView.layoutManager = linearLayoutManager
binding.homeRecyclerView.adapter = adapter
postViewModel.saveRecyclerViewLayout("cardMagazineLayout")
}
}
} catch (e: Exception) {
Log.e(TAG, "changeAndSaveLayout: " + e.message)
Log.e(TAG, "changeAndSaveLayout: " + e.cause)
}
}
} else if (orientation == 2) {
builder.setItems(
recyclerViewLandscapeLayout
) { _: DialogInterface?, index: Int ->
try {
when (index) {
2 -> {
adapter.viewType = 2
binding.homeRecyclerView.layoutManager = titleLayoutManager
binding.homeRecyclerView.adapter = adapter
postViewModel.saveRecyclerViewLayout("titleLayout")
}
3 -> {
adapter.viewType = 3
binding.homeRecyclerView.layoutManager = gridLayoutManager
binding.homeRecyclerView.adapter = adapter
postViewModel.saveRecyclerViewLayout("gridLayout")
}
}
} catch (e: Exception) {
Log.e(TAG, "changeAndSaveLayout: " + e.message)
Log.e(TAG, "changeAndSaveLayout: " + e.cause)
}
}
}
val alertDialog = builder.create()
alertDialog.show()
}
}
显示问题的 GIF
很长一段时间以来我一直在寻找一个灵魂，我找到了它并将它添加到我的旧项目中，我使用的是共享偏好但在你的情况下我的意思是数据存储它会正常工作
<?xml version="1.0" encoding="utf-8"?>
<resources>
<array name="recyclerViewPortraitList">
<item>Card List</item>
<item>Card Magazine</item>
<item>Title</item>
</array>
<array name="recyclerViewLandscapeList">
<item>Grid with 3 Span</item>
<item>Grid with 4 Span</item>
</array>
</resources>
private object PreferencesKeys {
var RECYCLER_VIEW_PORTRAIT_LAYOUT_KEY = stringPreferencesKey("recyclerViewPortraitLayout")
var RECYCLER_VIEW_LANDSCAPE_LAYOUT_KEY = stringPreferencesKey("recyclerViewLandscapeLayout")
}
suspend fun saveRecyclerViewPortraitLayout(
recyclerViewLayout: String,
) {
datastore.edit { preferences ->
preferences[PreferencesKeys.RECYCLER_VIEW_PORTRAIT_LAYOUT_KEY] = recyclerViewLayout
}
}
suspend fun saveRecyclerViewLandscapeLayout(recyclerViewLayout: String) {
datastore.edit { preferences ->
preferences[PreferencesKeys.RECYCLER_VIEW_LANDSCAPE_LAYOUT_KEY] = recyclerViewLayout
}
}
val readRecyclerViewPortraitLayout:
Flow<String> = datastore.data.catch { ex ->
if (ex is IOException) {
ex.message?.let { Log.e(TAG, it) }
emit(emptyPreferences())
} else {
throw ex
}
}.map { preferences ->
val recyclerViewLayout: String =
preferences[PreferencesKeys.RECYCLER_VIEW_PORTRAIT_LAYOUT_KEY] ?: "cardLayout"
recyclerViewLayout
}
val readRecyclerViewLandscpaeLayout:
Flow<String> = datastore.data.catch { ex ->
if (ex is IOException) {
ex.message?.let { Log.e(TAG, it) }
emit(emptyPreferences())
} else {
throw ex
}
}.map { preferences ->
val recyclerViewLayout: String =
preferences[PreferencesKeys.RECYCLER_VIEW_LANDSCAPE_LAYOUT_KEY] ?: "gridWith3Span"
recyclerViewLayout
}
val readRecyclerViewPortraitLayout =
dataStoreRepository.readRecyclerViewPortraitLayout.asLiveData()
val readRecyclerViewLandscapeLayout =
dataStoreRepository.readRecyclerViewLandscpaeLayout.asLiveData()
fun saveRecyclerViewPortraitLayout(layout: String) {
viewModelScope.launch {
dataStoreRepository.saveRecyclerViewPortraitLayout(layout)
}
}
fun saveRecyclerViewLandscapeLayout(layout: String) {
viewModelScope.launch {
dataStoreRepository.saveRecyclerViewLandscapeLayout(layout)
}
}
companion object {
private const val CARD = 0
private const val CARD_MAGAZINE = 1
private const val TITLE = 2
private const val GRID_WITH_3_SPAN = 3
private const val GRID_WITH_4_SPAN = 4
}
5.最后在片段或活动中你可以像下面这样使用它
private fun setUpRecyclerViewLayout() {
if (requireActivity().resources.configuration.orientation == Configuration.ORIENTATION_PORTRAIT) {
postViewModel.readRecyclerViewPortraitLayout.observe(viewLifecycleOwner) { layout ->
recyclerViewLayout = layout
when (layout) {
"cardLayout" -> {
adapter.viewType = 0
binding.apply {
homeRecyclerView.layoutManager = linearLayoutManager
homeRecyclerView.adapter = adapter
homeRecyclerView.setHasFixedSize(true)
}
}
"cardMagazineLayout" -> {
binding.homeRecyclerView.layoutManager = linearLayoutManager
adapter.viewType = 1
binding.homeRecyclerView.adapter = adapter
}
"titleLayout" -> {
binding.homeRecyclerView.layoutManager = titleLayoutManager
adapter.viewType = 2
binding.homeRecyclerView.adapter = adapter
}
}
}
} else {
postViewModel.readRecyclerViewLandscapeLayout.observe(viewLifecycleOwner) { layout ->
recyclerViewLayout = layout
when (layout) {
"gridWith3Span" -> {
binding.homeRecyclerView.layoutManager = gridWith3SpanLayoutManager
adapter.viewType = 3
binding.homeRecyclerView.adapter = adapter
}
"gridWith4Span" -> {
binding.homeRecyclerView.layoutManager = gridWith4SpanLayoutManager
adapter.viewType = 4
binding.homeRecyclerView.adapter = adapter
}
}
}
}
}
private fun changeAndSaveLayout() {
val builder = AlertDialog.Builder(requireContext())
builder.setTitle(getString(R.string.choose_layout))
// SharedPreferences.Editor editor = sharedPreferences.edit();
if (resources.configuration.orientation == Configuration.ORIENTATION_PORTRAIT) {
builder.setItems(
resources.getStringArray(R.array.recyclerViewPortraitList)
) { _: DialogInterface?, index: Int ->
try {
when (index) {
0 -> {
adapter.viewType = 0
binding.homeRecyclerView.layoutManager = linearLayoutManager
binding.homeRecyclerView.adapter = adapter
postViewModel.saveRecyclerViewPortraitLayout("cardLayout")
}
1 -> {
adapter.viewType = 1
binding.homeRecyclerView.layoutManager = linearLayoutManager
binding.homeRecyclerView.adapter = adapter
postViewModel.saveRecyclerViewPortraitLayout("cardMagazineLayout")
}
2 -> {
adapter.viewType = 2
binding.homeRecyclerView.layoutManager = titleLayoutManager
binding.homeRecyclerView.adapter = adapter
postViewModel.saveRecyclerViewPortraitLayout("titleLayout")
}
else -> {
throw Exception("Unknown layout")
}
}
} catch (e: Exception) {
Log.e(TAG, "changeAndSaveLayout: " + e.message)
Log.e(TAG, "changeAndSaveLayout: " + e.cause)
}
}
} else {
builder.setItems(
resources.getStringArray(R.array.recyclerViewLandscapeList)
) { _: DialogInterface?, index: Int ->
try {
when (index) {
0 -> {
adapter.viewType = 3
binding.homeRecyclerView.layoutManager = gridWith3SpanLayoutManager
binding.homeRecyclerView.adapter = adapter
postViewModel.saveRecyclerViewLandscapeLayout("gridWith3Span")
}
1 -> {
adapter.viewType = 4
binding.homeRecyclerView.layoutManager = gridWith4SpanLayoutManager
binding.homeRecyclerView.adapter = adapter
postViewModel.saveRecyclerViewLandscapeLayout("gridWith4Span")
}
else -> {
throw Exception("Unknown layout")
}
}
} catch (e: Exception) {
Log.e(TAG, "changeAndSaveLayout: " + e.message)
Log.e(TAG, "changeAndSaveLayout: " + e.cause)
}
}
}
val alertDialog = builder.create()
alertDialog.show()
}
如果您在清单中设置配置更改，如android:configChanges="orientation|screenSize"您将需要从onConfigurationChanged调用setUpRecyclerViewLayout()
override fun onConfigurationChanged(newConfig: Configuration) {
super.onConfigurationChanged(newConfig)
setUpRecyclerViewLayout()
}
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