使用 Recycler 视图在片段中实现 Viewpager2
Implementing Viewpager2 in a fragment with Recycler view
我正在尝试在片段中实现 viewpager2,该片段显示带有 Recycler View 的笔记列表。我尝试了不同的解决方案,但我无法弄明白。
这是我的 fragment_notes_list.xml :
<androidx.recyclerview.widget.RecyclerView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/notes_recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
list_item_notes.xml用于显示recycler view viewholder:
<androidx.cardview.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:id="@+id/card_pertanyaan"
android:layout_width="match_parent"
android:layout_height="96dp"
android:layout_marginLeft="16dp"
android:layout_marginTop="12dp"
android:layout_marginRight="16dp"
android:clickable="true"
android:foreground="?selectableItemBackground"
card_view:cardBackgroundColor="#595959"
card_view:cardCornerRadius="8dp"
card_view:contentPadding="10dp">
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/linearLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="@+id/notes_title"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="8dp"
android:text="Title"
android:textColor="@color/white"
app:layout_constraintBottom_toTopOf="@+id/notes_body"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_chainStyle="packed" />
<TextView
android:id="@+id/notes_body"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:textColor="@color/white"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/notes_title" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
来自片段 class NotesListFragment.kt 的相关片段:
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val view = inflater.inflate(R.layout.fragment_notes_list, container, false)
notesRecyclerView =
view.findViewById(R.id.notes_recycler_view) as RecyclerView
registerForContextMenu(notesRecyclerView)
notesRecyclerView.layoutManager = LinearLayoutManager(context)
notesRecyclerView.adapter = adapter
return view
}
private inner class ScreenSlidePagerAdapter(fa: Fragment) : FragmentStateAdapter(fa) {
override fun getItemCount(): Int = NUM_PAGES
override fun createFragment(position: Int): Fragment {
return if (position == 0) {
NotesListFragment()
} else {
CalenderFragment()
}
}
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
notesListViewModel.notesListLiveData.observe(
viewLifecycleOwner,
Observer { notes ->
notes?.let {
Log.i(TAG, "got notes")
updateUI(notes)
}
})
}
private inner class NotesAdapter(var notes: List<Notes>) : RecyclerView.Adapter<NotesHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): NotesHolder {
val view = layoutInflater.inflate(R.layout.list_item_notes, parent, false)
/* viewPager = view.findViewById(R.id.pager)
val pagerAdapter = ScreenSlidePagerAdapter(this@NotesListFragment)
viewPager.adapter = pagerAdapter */
return NotesHolder(view)
}
override fun getItemCount() = notes.size
override fun onBindViewHolder(holder: NotesHolder, position: Int) {
val note = notes[position]
holder.bind(note)
}
}
我很困惑是否应该在 list_item_notes.xml 中添加 ViewPager2 和 FrameLayout?
但是我该如何为它实现 ScreenSliderPagerAdapter 呢?
我假设您想要 2 个片段:列表和日历,这就是您需要实现 ViewPager2 的原因。您的 NotesListFragment 看起来不错。你有 recyclerview 那里有注释,但你现在想要的是提供 NotesListFragment 和 CalendarFragment 的列表,它们可以在 left/right 方向滚动。首先,在片段代码之外提取 ScreenSlidePagerAdapter。接下来,您必须将 ViewPager2 添加到 parent activity/fragment
<androidx.viewpager2.widget.ViewPager2
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent" />
然后在您的 parent activity/fragment 中像这样将它与适配器配对:
val viewPager = findViewById(R.id.pager)
val pagerAdapter = ScreenSlidePagerAdapter(this)
viewPager.adapter = pagerAdapter
您可以在官方文档中阅读更多相关信息:https://developer.android.com/training/animation/screen-slide-2
我之前也曾尝试在 Main Activity 中实现 ViewPager。但是这样我就无法关闭 viewpager 片段,因为它们始终可见。我该如何解决这个问题?
这是我的主要 activity 在您建议的更改之后:
class MainActivity : AppCompatActivity(),
NotesListFragment.Callbacks {
private lateinit var viewPager: ViewPager2
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
viewPager = findViewById(R.id.pager)
val pagerAdapter = ScreenSlidePagerAdapter(this)
viewPager.adapter = pagerAdapter
}
override fun onNotesSelected(notesId: UUID) {
val fragment = NotesFragment.newInstance(notesId)
supportFragmentManager
.beginTransaction()
.replace(R.id.fragment_container, fragment)
.addToBackStack(null)
.commit()
}
fun onNotesDeleted(notes: Notes) {
val fragment = NotesListFragment()
supportFragmentManager
.beginTransaction()
.replace(R.id.fragment_container, fragment)
.commit()
Toast.makeText(this, "Note Deleted", Toast.LENGTH_SHORT).show()
}
mainactivity.xml:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.viewpager2.widget.ViewPager2
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/pager"/>
</FrameLayout>
这里是一些截图,
https://drive.google.com/drive/folders/13ITZqcaeDeydCe0tW2Iu7VoSGSZnrlkg?usp=sharing
问题解决了。
因为我无法添加带有 NotesListFragment 回收视图的 Viewpager,所以我用 viewpager 制作了另一个父片段并将 NotesListFragment 放入其中。
我正在尝试在片段中实现 viewpager2,该片段显示带有 Recycler View 的笔记列表。我尝试了不同的解决方案,但我无法弄明白。
这是我的 fragment_notes_list.xml :
<androidx.recyclerview.widget.RecyclerView
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/notes_recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
list_item_notes.xml用于显示recycler view viewholder:
<androidx.cardview.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:id="@+id/card_pertanyaan"
android:layout_width="match_parent"
android:layout_height="96dp"
android:layout_marginLeft="16dp"
android:layout_marginTop="12dp"
android:layout_marginRight="16dp"
android:clickable="true"
android:foreground="?selectableItemBackground"
card_view:cardBackgroundColor="#595959"
card_view:cardCornerRadius="8dp"
card_view:contentPadding="10dp">
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/linearLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="@+id/notes_title"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="8dp"
android:text="Title"
android:textColor="@color/white"
app:layout_constraintBottom_toTopOf="@+id/notes_body"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_chainStyle="packed" />
<TextView
android:id="@+id/notes_body"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:textColor="@color/white"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/notes_title" />
</androidx.constraintlayout.widget.ConstraintLayout>
</androidx.cardview.widget.CardView>
来自片段 class NotesListFragment.kt 的相关片段:
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
val view = inflater.inflate(R.layout.fragment_notes_list, container, false)
notesRecyclerView =
view.findViewById(R.id.notes_recycler_view) as RecyclerView
registerForContextMenu(notesRecyclerView)
notesRecyclerView.layoutManager = LinearLayoutManager(context)
notesRecyclerView.adapter = adapter
return view
}
private inner class ScreenSlidePagerAdapter(fa: Fragment) : FragmentStateAdapter(fa) {
override fun getItemCount(): Int = NUM_PAGES
override fun createFragment(position: Int): Fragment {
return if (position == 0) {
NotesListFragment()
} else {
CalenderFragment()
}
}
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
notesListViewModel.notesListLiveData.observe(
viewLifecycleOwner,
Observer { notes ->
notes?.let {
Log.i(TAG, "got notes")
updateUI(notes)
}
})
}
private inner class NotesAdapter(var notes: List<Notes>) : RecyclerView.Adapter<NotesHolder>() {
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): NotesHolder {
val view = layoutInflater.inflate(R.layout.list_item_notes, parent, false)
/* viewPager = view.findViewById(R.id.pager)
val pagerAdapter = ScreenSlidePagerAdapter(this@NotesListFragment)
viewPager.adapter = pagerAdapter */
return NotesHolder(view)
}
override fun getItemCount() = notes.size
override fun onBindViewHolder(holder: NotesHolder, position: Int) {
val note = notes[position]
holder.bind(note)
}
}
我很困惑是否应该在 list_item_notes.xml 中添加 ViewPager2 和 FrameLayout? 但是我该如何为它实现 ScreenSliderPagerAdapter 呢?
我假设您想要 2 个片段:列表和日历,这就是您需要实现 ViewPager2 的原因。您的 NotesListFragment 看起来不错。你有 recyclerview 那里有注释,但你现在想要的是提供 NotesListFragment 和 CalendarFragment 的列表,它们可以在 left/right 方向滚动。首先,在片段代码之外提取 ScreenSlidePagerAdapter。接下来,您必须将 ViewPager2 添加到 parent activity/fragment
<androidx.viewpager2.widget.ViewPager2
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent" />
然后在您的 parent activity/fragment 中像这样将它与适配器配对:
val viewPager = findViewById(R.id.pager)
val pagerAdapter = ScreenSlidePagerAdapter(this)
viewPager.adapter = pagerAdapter
您可以在官方文档中阅读更多相关信息:https://developer.android.com/training/animation/screen-slide-2
我之前也曾尝试在 Main Activity 中实现 ViewPager。但是这样我就无法关闭 viewpager 片段,因为它们始终可见。我该如何解决这个问题?
这是我的主要 activity 在您建议的更改之后:
class MainActivity : AppCompatActivity(),
NotesListFragment.Callbacks {
private lateinit var viewPager: ViewPager2
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
viewPager = findViewById(R.id.pager)
val pagerAdapter = ScreenSlidePagerAdapter(this)
viewPager.adapter = pagerAdapter
}
override fun onNotesSelected(notesId: UUID) {
val fragment = NotesFragment.newInstance(notesId)
supportFragmentManager
.beginTransaction()
.replace(R.id.fragment_container, fragment)
.addToBackStack(null)
.commit()
}
fun onNotesDeleted(notes: Notes) {
val fragment = NotesListFragment()
supportFragmentManager
.beginTransaction()
.replace(R.id.fragment_container, fragment)
.commit()
Toast.makeText(this, "Note Deleted", Toast.LENGTH_SHORT).show()
}
mainactivity.xml:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.viewpager2.widget.ViewPager2
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/pager"/>
</FrameLayout>
这里是一些截图,
https://drive.google.com/drive/folders/13ITZqcaeDeydCe0tW2Iu7VoSGSZnrlkg?usp=sharing
问题解决了。
因为我无法添加带有 NotesListFragment 回收视图的 Viewpager,所以我用 viewpager 制作了另一个父片段并将 NotesListFragment 放入其中。