Migrate from ViewPager to ViewPager2 (#1601)

app/src/main/java/io/github/wulkanowy/ui/base/BaseFragmentPagerAdapter.kt

@@ -2,32 +2,33 @@ package io.github.wulkanowy.ui.base
 
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.FragmentManager
-import androidx.fragment.app.FragmentPagerAdapter
+import androidx.lifecycle.Lifecycle
+import androidx.viewpager2.adapter.FragmentStateAdapter
+import com.google.android.material.tabs.TabLayout
+import com.google.android.material.tabs.TabLayoutMediator
 
-//TODO  Use ViewPager2
+class BaseFragmentPagerAdapter(
-class BaseFragmentPagerAdapter(private val fragmentManager: FragmentManager) :
+    private val fragmentManager: FragmentManager,
-    FragmentPagerAdapter(fragmentManager, BEHAVIOR_RESUME_ONLY_CURRENT_FRAGMENT) {
+    private val pagesCount: Int,
+    lifecycle: Lifecycle,
+) : FragmentStateAdapter(fragmentManager, lifecycle), TabLayoutMediator.TabConfigurationStrategy {
 
-    private val pages = mutableMapOf<Fragment, String?>()
+    lateinit var itemFactory: (position: Int) -> Fragment
+
+    var titleFactory: (position: Int) -> String? = { "" }
 
     var containerId = 0
 
     fun getFragmentInstance(position: Int): Fragment? {
         require(containerId != 0) { "Container id is 0" }
-        return fragmentManager.findFragmentByTag("android:switcher:$containerId:$position")
+        return fragmentManager.findFragmentByTag("f$position")
     }
 
-    fun addFragments(fragments: List<Fragment>) {
+    override fun createFragment(position: Int): Fragment = itemFactory(position)
-        fragments.forEach { pages[it] = null }
+
+    override fun getItemCount() = pagesCount
+
+    override fun onConfigureTab(tab: TabLayout.Tab, position: Int) {
+        tab.text = titleFactory(position)
     }
-
-    fun addFragmentsWithTitle(pages: Map<Fragment, String>) {
-        this.pages.putAll(pages)
-    }
-
-    override fun getItem(position: Int) = pages.keys.elementAt(position)
-
-    override fun getCount() = pages.size
-
-    override fun getPageTitle(position: Int) = pages.values.elementAt(position)
 }

app/src/main/java/io/github/wulkanowy/ui/modules/grade/GradeFragment.kt

@@ -8,6 +8,7 @@ import android.view.View
 import android.view.View.INVISIBLE
 import android.view.View.VISIBLE
 import androidx.appcompat.app.AlertDialog
+import com.google.android.material.tabs.TabLayoutMediator
 import dagger.hilt.android.AndroidEntryPoint
 import io.github.wulkanowy.R
 import io.github.wulkanowy.data.db.entities.Semester
@@ -29,7 +30,13 @@ class GradeFragment : BaseFragment<FragmentGradeBinding>(R.layout.fragment_grade
     @Inject
     lateinit var presenter: GradePresenter
 
-    private val pagerAdapter by lazy { BaseFragmentPagerAdapter(childFragmentManager) }
+    private val pagerAdapter by lazy {
+        BaseFragmentPagerAdapter(
+            fragmentManager = childFragmentManager,
+            pagesCount = 3,
+            lifecycle = lifecycle,
+        )
+    }
 
     private var semesterSwitchMenu: MenuItem? = null
 
@@ -62,25 +69,34 @@ class GradeFragment : BaseFragment<FragmentGradeBinding>(R.layout.fragment_grade
     }
 
     override fun initView() {
-        with(pagerAdapter) {
-            containerId = binding.gradeViewPager.id
-            addFragmentsWithTitle(
-                mapOf(
-                    GradeDetailsFragment.newInstance() to getString(R.string.all_details),
-                    GradeSummaryFragment.newInstance() to getString(R.string.grade_menu_summary),
-                    GradeStatisticsFragment.newInstance() to getString(R.string.grade_menu_statistics)
-                )
-            )
-        }
-
         with(binding.gradeViewPager) {
             adapter = pagerAdapter
             offscreenPageLimit = 3
             setOnSelectPageListener(presenter::onPageSelected)
         }
 
+        with(pagerAdapter) {
+            containerId = binding.gradeViewPager.id
+            titleFactory = {
+                when (it) {
+                    0 -> getString(R.string.all_details)
+                    1 -> getString(R.string.grade_menu_summary)
+                    2 -> getString(R.string.grade_menu_statistics)
+                    else -> throw IllegalStateException()
+                }
+            }
+            itemFactory = {
+                when (it) {
+                    0 -> GradeDetailsFragment.newInstance()
+                    1 -> GradeSummaryFragment.newInstance()
+                    2 -> GradeStatisticsFragment.newInstance()
+                    else -> throw IllegalStateException()
+                }
+            }
+            TabLayoutMediator(binding.gradeTabLayout, binding.gradeViewPager, this).attach()
+        }
+
         with(binding.gradeTabLayout) {
-            setupWithViewPager(binding.gradeViewPager)
             setElevationCompat(context.dpToPx(4f))
         }
 

app/src/main/java/io/github/wulkanowy/ui/modules/grade/GradePresenter.kt

@@ -101,7 +101,6 @@ class GradePresenter @Inject constructor(
     private fun loadData() {
         flowWithResource {
             val student = studentRepository.getCurrentStudent()
-            delay(200)
             semesterRepository.getSemesters(student, refreshOnNoCurrent = true)
         }.onEach {
             when (it.status) {

app/src/main/java/io/github/wulkanowy/ui/modules/login/LoginActivity.kt

@@ -24,7 +24,13 @@ class LoginActivity : BaseActivity<LoginPresenter, ActivityLoginBinding>(), Logi
     @Inject
     override lateinit var presenter: LoginPresenter
 
-    private val loginAdapter = BaseFragmentPagerAdapter(supportFragmentManager)
+    private val pagerAdapter by lazy {
+        BaseFragmentPagerAdapter(
+            fragmentManager = supportFragmentManager,
+            pagesCount = 5,
+            lifecycle = lifecycle,
+        )
+    }
 
     @Inject
     lateinit var updateHelper: UpdateHelper
@@ -65,24 +71,26 @@ class LoginActivity : BaseActivity<LoginPresenter, ActivityLoginBinding>(), Logi
             setDisplayShowTitleEnabled(false)
         }
 
-        with(loginAdapter) {
-            containerId = binding.loginViewpager.id
-            addFragments(
-                listOf(
-                    LoginFormFragment.newInstance(),
-                    LoginSymbolFragment.newInstance(),
-                    LoginStudentSelectFragment.newInstance(),
-                    LoginAdvancedFragment.newInstance(),
-                    LoginRecoverFragment.newInstance()
-                )
-            )
-        }
-
         with(binding.loginViewpager) {
             offscreenPageLimit = 2
-            adapter = loginAdapter
+            adapter = pagerAdapter
+            isUserInputEnabled = false
             setOnSelectPageListener(presenter::onViewSelected)
         }
+
+        with(pagerAdapter) {
+            containerId = binding.loginViewpager.id
+            itemFactory = {
+                when (it) {
+                    0 -> LoginFormFragment.newInstance()
+                    1 -> LoginSymbolFragment.newInstance()
+                    2 -> LoginStudentSelectFragment.newInstance()
+                    3 -> LoginAdvancedFragment.newInstance()
+                    4 -> LoginRecoverFragment.newInstance()
+                    else -> throw IllegalStateException()
+                }
+            }
+        }
     }
 
     override fun onOptionsItemSelected(item: MenuItem): Boolean {
@@ -103,12 +111,12 @@ class LoginActivity : BaseActivity<LoginPresenter, ActivityLoginBinding>(), Logi
     }
 
     override fun notifyInitSymbolFragment(loginData: Triple<String, String, String>) {
-        (loginAdapter.getFragmentInstance(1) as? LoginSymbolFragment)
+        (pagerAdapter.getFragmentInstance(1) as? LoginSymbolFragment)
             ?.onParentInitSymbolFragment(loginData)
     }
 
     override fun notifyInitStudentSelectFragment(studentsWithSemesters: List<StudentWithSemesters>) {
-        (loginAdapter.getFragmentInstance(2) as? LoginStudentSelectFragment)
+        (pagerAdapter.getFragmentInstance(2) as? LoginStudentSelectFragment)
             ?.onParentInitStudentSelectFragment(studentsWithSemesters)
     }
 

app/src/main/java/io/github/wulkanowy/ui/modules/message/MessageFragment.kt

@@ -4,6 +4,7 @@ import android.os.Bundle
 import android.view.View
 import android.view.View.INVISIBLE
 import android.view.View.VISIBLE
+import com.google.android.material.tabs.TabLayoutMediator
 import dagger.hilt.android.AndroidEntryPoint
 import io.github.wulkanowy.R
 import io.github.wulkanowy.data.enums.MessageFolder.RECEIVED
@@ -26,7 +27,13 @@ class MessageFragment : BaseFragment<FragmentMessageBinding>(R.layout.fragment_m
     @Inject
     lateinit var presenter: MessagePresenter
 
-    private val pagerAdapter by lazy { BaseFragmentPagerAdapter(childFragmentManager) }
+    private val pagerAdapter by lazy {
+        BaseFragmentPagerAdapter(
+            fragmentManager = childFragmentManager,
+            pagesCount = 3,
+            lifecycle = lifecycle,
+        )
+    }
 
     companion object {
         fun newInstance() = MessageFragment()
@@ -43,23 +50,34 @@ class MessageFragment : BaseFragment<FragmentMessageBinding>(R.layout.fragment_m
     }
 
     override fun initView() {
-        with(pagerAdapter) {
-            containerId = binding.messageViewPager.id
-            addFragmentsWithTitle(mapOf(
-                MessageTabFragment.newInstance(RECEIVED) to getString(R.string.message_inbox),
-                MessageTabFragment.newInstance(SENT) to getString(R.string.message_sent),
-                MessageTabFragment.newInstance(TRASHED) to getString(R.string.message_trash)
-            ))
-        }
-
         with(binding.messageViewPager) {
             adapter = pagerAdapter
             offscreenPageLimit = 2
             setOnSelectPageListener(presenter::onPageSelected)
         }
 
+        with(pagerAdapter) {
+            containerId = binding.messageViewPager.id
+            titleFactory = {
+                when (it) {
+                    0 -> getString(R.string.message_inbox)
+                    1 -> getString(R.string.message_sent)
+                    2 -> getString(R.string.message_trash)
+                    else -> throw IllegalStateException()
+                }
+            }
+            itemFactory = {
+                when (it) {
+                    0 -> MessageTabFragment.newInstance(RECEIVED)
+                    1 -> MessageTabFragment.newInstance(SENT)
+                    2 -> MessageTabFragment.newInstance(TRASHED)
+                    else -> throw IllegalStateException()
+                }
+            }
+            TabLayoutMediator(binding.messageTabLayout, binding.messageViewPager, this).attach()
+        }
+
         with(binding.messageTabLayout) {
-            setupWithViewPager(binding.messageViewPager)
             setElevationCompat(context.dpToPx(4f))
         }
 

app/src/main/java/io/github/wulkanowy/ui/modules/message/MessagePresenter.kt

@@ -16,7 +16,6 @@ class MessagePresenter @Inject constructor(
     override fun onAttachView(view: MessageView) {
         super.onAttachView(view)
         presenterScope.launch {
-            delay(150)
             view.initView()
             Timber.i("Message view was initialized")
             loadData()

app/src/main/java/io/github/wulkanowy/ui/modules/schoolandteachers/SchoolAndTeachersFragment.kt

@@ -4,6 +4,7 @@ import android.os.Bundle
 import android.view.View
 import android.view.View.INVISIBLE
 import android.view.View.VISIBLE
+import com.google.android.material.tabs.TabLayoutMediator
 import dagger.hilt.android.AndroidEntryPoint
 import io.github.wulkanowy.R
 import io.github.wulkanowy.databinding.FragmentSchoolandteachersBinding
@@ -24,7 +25,13 @@ class SchoolAndTeachersFragment :
     @Inject
     lateinit var presenter: SchoolAndTeachersPresenter
 
-    private val pagerAdapter by lazy { BaseFragmentPagerAdapter(childFragmentManager) }
+    private val pagerAdapter by lazy {
+        BaseFragmentPagerAdapter(
+            fragmentManager = childFragmentManager,
+            pagesCount = 2,
+            lifecycle = lifecycle,
+        )
+    }
 
     companion object {
         fun newInstance() = SchoolAndTeachersFragment()
@@ -41,22 +48,36 @@ class SchoolAndTeachersFragment :
     }
 
     override fun initView() {
-        with(pagerAdapter) {
-            containerId = binding.schoolandteachersViewPager.id
-            addFragmentsWithTitle(mapOf(
-                SchoolFragment.newInstance() to getString(R.string.school_title),
-                TeacherFragment.newInstance() to getString(R.string.teachers_title)
-            ))
-        }
-
         with(binding.schoolandteachersViewPager) {
             adapter = pagerAdapter
             offscreenPageLimit = 2
             setOnSelectPageListener(presenter::onPageSelected)
         }
 
+        with(pagerAdapter) {
+            containerId = binding.schoolandteachersViewPager.id
+            titleFactory = {
+                when (it) {
+                    0 -> getString(R.string.school_title)
+                    1 -> getString(R.string.teachers_title)
+                    else -> throw IllegalStateException()
+                }
+            }
+            itemFactory = {
+                when (it) {
+                    0 -> SchoolFragment.newInstance()
+                    1 -> TeacherFragment.newInstance()
+                    else -> throw IllegalStateException()
+                }
+            }
+            TabLayoutMediator(
+                binding.schoolandteachersTabLayout,
+                binding.schoolandteachersViewPager,
+                this
+            ).attach()
+        }
+
         with(binding.schoolandteachersTabLayout) {
-            setupWithViewPager(binding.schoolandteachersViewPager)
             setElevationCompat(context.dpToPx(4f))
         }
     }
@@ -77,7 +98,8 @@ class SchoolAndTeachersFragment :
     }
 
     override fun notifyChildLoadData(index: Int, forceRefresh: Boolean) {
-        (pagerAdapter.getFragmentInstance(index) as? SchoolAndTeachersChildView)?.onParentLoadData(forceRefresh)
+        (pagerAdapter.getFragmentInstance(index) as? SchoolAndTeachersChildView)
+            ?.onParentLoadData(forceRefresh)
     }
 
     override fun onDestroyView() {

app/src/main/java/io/github/wulkanowy/ui/modules/schoolandteachers/SchoolAndTeachersPresenter.kt

@@ -16,7 +16,6 @@ class SchoolAndTeachersPresenter @Inject constructor(
     override fun onAttachView(view: SchoolAndTeachersView) {
         super.onAttachView(view)
         presenterScope.launch {
-            delay(150)
             view.initView()
             Timber.i("Message view was initialized")
             loadData()

app/src/main/java/io/github/wulkanowy/ui/widgets/SwipeDisabledViewPager.kt

@@ -1,19 +0,0 @@
-package io.github.wulkanowy.ui.widgets
-
-import android.annotation.SuppressLint
-import android.content.Context
-import android.util.AttributeSet
-import android.view.MotionEvent
-import androidx.viewpager.widget.ViewPager
-
-class SwipeDisabledViewPager : ViewPager {
-
-    constructor(context: Context) : super(context)
-
-    constructor(context: Context, attr: AttributeSet) : super(context, attr)
-
-    @SuppressLint("ClickableViewAccessibility")
-    override fun onTouchEvent(ev: MotionEvent) = false
-
-    override fun onInterceptTouchEvent(ev: MotionEvent) = false
-}

app/src/main/java/io/github/wulkanowy/utils/ViewPagerExtension.kt

@@ -1,13 +1,11 @@
 package io.github.wulkanowy.utils
 
-import androidx.viewpager.widget.ViewPager
+import androidx.viewpager2.widget.ViewPager2
 
-inline fun ViewPager.setOnSelectPageListener(crossinline selectListener: (position: Int) -> Unit) {
+inline fun ViewPager2.setOnSelectPageListener(crossinline selectListener: (position: Int) -> Unit) {
-    addOnPageChangeListener(object : ViewPager.OnPageChangeListener {
+    registerOnPageChangeCallback(object : ViewPager2.OnPageChangeCallback() {
         override fun onPageSelected(position: Int) {
             selectListener(position)
         }
-        override fun onPageScrollStateChanged(state: Int) {}
-        override fun onPageScrolled(position: Int, positionOffset: Float, positionOffsetPixels: Int) {}
     })
 }

app/src/main/res/layout/activity_login.xml

@@ -10,7 +10,7 @@
         android:layout_height="wrap_content"
         android:background="@android:color/transparent" />
 
-    <io.github.wulkanowy.ui.widgets.SwipeDisabledViewPager
+    <androidx.viewpager2.widget.ViewPager2
         android:id="@+id/loginViewpager"
         android:layout_width="match_parent"
         android:layout_height="match_parent" />

app/src/main/res/layout/fragment_grade.xml

@@ -17,7 +17,7 @@
         tools:ignore="UnusedAttribute"
         tools:visibility="visible" />
 
-    <androidx.viewpager.widget.ViewPager
+    <androidx.viewpager2.widget.ViewPager2
         android:id="@+id/gradeViewPager"
         android:layout_width="match_parent"
         android:layout_height="match_parent"

app/src/main/res/layout/fragment_message.xml

@@ -20,7 +20,7 @@
         tools:ignore="UnusedAttribute"
         tools:visibility="visible" />
 
-    <androidx.viewpager.widget.ViewPager
+    <androidx.viewpager2.widget.ViewPager2
         android:id="@+id/messageViewPager"
         android:layout_width="match_parent"
         android:layout_height="match_parent"

app/src/main/res/layout/fragment_schoolandteachers.xml

@@ -20,7 +20,7 @@
         tools:ignore="UnusedAttribute"
         tools:visibility="visible" />
 
-    <androidx.viewpager.widget.ViewPager
+    <androidx.viewpager2.widget.ViewPager2
         android:id="@+id/schoolandteachersViewPager"
         android:layout_width="match_parent"
         android:layout_height="match_parent"