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Add fix for BottomNavigationView from NavigationAdvancedSample
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PStrelchenko committed Aug 15, 2020
1 parent 7d54b32 commit 56a7894
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59 changes: 46 additions & 13 deletions app/src/main/java/com/aaglobal/jnc_playground/RootActivity.kt
@@ -1,26 +1,59 @@
package com.aaglobal.jnc_playground

import android.os.Bundle
import com.google.android.material.bottomnavigation.BottomNavigationView
import androidx.appcompat.app.AppCompatActivity
import androidx.navigation.findNavController
import androidx.navigation.ui.AppBarConfiguration
import androidx.lifecycle.LiveData
import androidx.lifecycle.Observer
import androidx.navigation.NavController
import androidx.navigation.ui.setupActionBarWithNavController
import androidx.navigation.ui.setupWithNavController
import com.aaglobal.jnc_playground.extensions.setupWithNavController
import com.google.android.material.bottomnavigation.BottomNavigationView

class RootActivity : AppCompatActivity() {

private var currentNavController: LiveData<NavController>? = null


override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_root)
val navView: BottomNavigationView = findViewById(R.id.nav_view)

val 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.
val appBarConfiguration = AppBarConfiguration(setOf(
R.id.navigation_home, R.id.navigation_dashboard, R.id.navigation_notifications))
setupActionBarWithNavController(navController, appBarConfiguration)
navView.setupWithNavController(navController)
if (savedInstanceState == null) {
setupBottomNavigationBar()
} // Else, need to wait for onRestoreInstanceState
}

override fun onRestoreInstanceState(savedInstanceState: Bundle) {
super.onRestoreInstanceState(savedInstanceState)
// Now that BottomNavigationBar has restored its instance state
// and its selectedItemId, we can proceed with setting up the
// BottomNavigationBar with Navigation
setupBottomNavigationBar()
}

/**
* Called on first creation and when restoring state.
*/
private fun setupBottomNavigationBar() {
val bottomNavigationView = findViewById<BottomNavigationView>(R.id.bottom_nav)

val navGraphIds = listOf(R.navigation.home_nav_graph, R.navigation.dashboard_nav_graph, R.navigation.notifications_nav_graph)

// Setup the bottom navigation view with a list of navigation graphs
val controller = bottomNavigationView.setupWithNavController(
navGraphIds = navGraphIds,
fragmentManager = supportFragmentManager,
containerId = R.id.nav_host_container,
intent = intent
)

// Whenever the selected controller changes, setup the action bar.
controller.observe(this, Observer { navController ->
setupActionBarWithNavController(navController)
})
currentNavController = controller
}

override fun onSupportNavigateUp(): Boolean {
return currentNavController?.value?.navigateUp() ?: false
}
}
@@ -0,0 +1,235 @@
package com.aaglobal.jnc_playground.extensions

import android.content.Intent
import android.util.SparseArray
import androidx.core.util.forEach
import androidx.core.util.set
import androidx.fragment.app.FragmentManager
import androidx.lifecycle.LiveData
import androidx.lifecycle.MutableLiveData
import androidx.navigation.NavController
import androidx.navigation.fragment.NavHostFragment
import com.aaglobal.jnc_playground.R
import com.google.android.material.bottomnavigation.BottomNavigationView

/**
* Manages the various graphs needed for a [BottomNavigationView].
*
* This sample is a workaround until the Navigation Component supports multiple back stacks.
*/
fun BottomNavigationView.setupWithNavController(
navGraphIds: List<Int>,
fragmentManager: FragmentManager,
containerId: Int,
intent: Intent
): LiveData<NavController> {

// Map of tags
val graphIdToTagMap = SparseArray<String>()
// Result. Mutable live data with the selected controlled
val selectedNavController = MutableLiveData<NavController>()

var firstFragmentGraphId = 0

// First create a NavHostFragment for each NavGraph ID
navGraphIds.forEachIndexed { index, navGraphId ->
val fragmentTag = getFragmentTag(index)

// Find or create the Navigation host fragment
val navHostFragment = obtainNavHostFragment(
fragmentManager,
fragmentTag,
navGraphId,
containerId
)

// Obtain its id
val graphId = navHostFragment.navController.graph.id

if (index == 0) {
firstFragmentGraphId = graphId
}

// Save to the map
graphIdToTagMap[graphId] = fragmentTag

// Attach or detach nav host fragment depending on whether it's the selected item.
if (this.selectedItemId == graphId) {
// Update livedata with the selected graph
selectedNavController.value = navHostFragment.navController
attachNavHostFragment(fragmentManager, navHostFragment, index == 0)
} else {
detachNavHostFragment(fragmentManager, navHostFragment)
}
}

// Now connect selecting an item with swapping Fragments
var selectedItemTag = graphIdToTagMap[this.selectedItemId]
val firstFragmentTag = graphIdToTagMap[firstFragmentGraphId]
var isOnFirstFragment = selectedItemTag == firstFragmentTag

// When a navigation item is selected
setOnNavigationItemSelectedListener { item ->
// Don't do anything if the state is state has already been saved.
if (fragmentManager.isStateSaved) {
false
} else {
val newlySelectedItemTag = graphIdToTagMap[item.itemId]
if (selectedItemTag != newlySelectedItemTag) {
// Pop everything above the first fragment (the "fixed start destination")
fragmentManager.popBackStack(firstFragmentTag,
FragmentManager.POP_BACK_STACK_INCLUSIVE)
val selectedFragment = fragmentManager.findFragmentByTag(newlySelectedItemTag)
as NavHostFragment

// Exclude the first fragment tag because it's always in the back stack.
if (firstFragmentTag != newlySelectedItemTag) {
// Commit a transaction that cleans the back stack and adds the first fragment
// to it, creating the fixed started destination.
fragmentManager.beginTransaction()
.setCustomAnimations(
R.anim.nav_default_enter_anim,
R.anim.nav_default_exit_anim,
R.anim.nav_default_pop_enter_anim,
R.anim.nav_default_pop_exit_anim)
.attach(selectedFragment)
.setPrimaryNavigationFragment(selectedFragment)
.apply {
// Detach all other Fragments
graphIdToTagMap.forEach { _, fragmentTagIter ->
if (fragmentTagIter != newlySelectedItemTag) {
detach(fragmentManager.findFragmentByTag(firstFragmentTag)!!)
}
}
}
.addToBackStack(firstFragmentTag)
.setReorderingAllowed(true)
.commit()
}
selectedItemTag = newlySelectedItemTag
isOnFirstFragment = selectedItemTag == firstFragmentTag
selectedNavController.value = selectedFragment.navController
true
} else {
false
}
}
}

// Optional: on item reselected, pop back stack to the destination of the graph
setupItemReselected(graphIdToTagMap, fragmentManager)

// Handle deep link
setupDeepLinks(navGraphIds, fragmentManager, containerId, intent)

// Finally, ensure that we update our BottomNavigationView when the back stack changes
fragmentManager.addOnBackStackChangedListener {
if (!isOnFirstFragment && !fragmentManager.isOnBackStack(firstFragmentTag)) {
this.selectedItemId = firstFragmentGraphId
}

// Reset the graph if the currentDestination is not valid (happens when the back
// stack is popped after using the back button).
selectedNavController.value?.let { controller ->
if (controller.currentDestination == null) {
controller.navigate(controller.graph.id)
}
}
}
return selectedNavController
}

private fun BottomNavigationView.setupDeepLinks(
navGraphIds: List<Int>,
fragmentManager: FragmentManager,
containerId: Int,
intent: Intent
) {
navGraphIds.forEachIndexed { index, navGraphId ->
val fragmentTag = getFragmentTag(index)

// Find or create the Navigation host fragment
val navHostFragment = obtainNavHostFragment(
fragmentManager,
fragmentTag,
navGraphId,
containerId
)
// Handle Intent
if (navHostFragment.navController.handleDeepLink(intent)
&& selectedItemId != navHostFragment.navController.graph.id) {
this.selectedItemId = navHostFragment.navController.graph.id
}
}
}

private fun BottomNavigationView.setupItemReselected(
graphIdToTagMap: SparseArray<String>,
fragmentManager: FragmentManager
) {
setOnNavigationItemReselectedListener { item ->
val newlySelectedItemTag = graphIdToTagMap[item.itemId]
val selectedFragment = fragmentManager.findFragmentByTag(newlySelectedItemTag)
as NavHostFragment
val navController = selectedFragment.navController
// Pop the back stack to the start destination of the current navController graph
navController.popBackStack(
navController.graph.startDestination, false
)
}
}

private fun detachNavHostFragment(
fragmentManager: FragmentManager,
navHostFragment: NavHostFragment
) {
fragmentManager.beginTransaction()
.detach(navHostFragment)
.commitNow()
}

private fun attachNavHostFragment(
fragmentManager: FragmentManager,
navHostFragment: NavHostFragment,
isPrimaryNavFragment: Boolean
) {
fragmentManager.beginTransaction()
.attach(navHostFragment)
.apply {
if (isPrimaryNavFragment) {
setPrimaryNavigationFragment(navHostFragment)
}
}
.commitNow()

}

private fun obtainNavHostFragment(
fragmentManager: FragmentManager,
fragmentTag: String,
navGraphId: Int,
containerId: Int
): NavHostFragment {
// If the Nav Host fragment exists, return it
val existingFragment = fragmentManager.findFragmentByTag(fragmentTag) as NavHostFragment?
existingFragment?.let { return it }

// Otherwise, create it and return it.
val navHostFragment = NavHostFragment.create(navGraphId)
fragmentManager.beginTransaction()
.add(containerId, navHostFragment, fragmentTag)
.commitNow()
return navHostFragment
}

private fun FragmentManager.isOnBackStack(backStackName: String): Boolean {
val backStackCount = backStackEntryCount
for (index in 0 until backStackCount) {
if (getBackStackEntryAt(index).name == backStackName) {
return true
}
}
return false
}

private fun getFragmentTag(index: Int) = "bottomNavigation#$index"
35 changes: 11 additions & 24 deletions app/src/main/res/layout/activity_root.xml
@@ -1,33 +1,20 @@
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingTop="?attr/actionBarSize">
android:orientation="vertical">

<androidx.fragment.app.FragmentContainerView
android:id="@+id/nav_host_container"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1" />

<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="@+id/nav_view"
android:layout_width="0dp"
android:id="@+id/bottom_nav"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="0dp"
android:layout_marginEnd="0dp"
android:background="?android:attr/windowBackground"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:menu="@menu/bottom_nav_menu" />

<fragment
android:id="@+id/nav_host_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:defaultNavHost="true"
app:layout_constraintBottom_toTopOf="@id/nav_view"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:navGraph="@navigation/mobile_navigation" />

</androidx.constraintlayout.widget.ConstraintLayout>
</LinearLayout>
Expand Up @@ -2,17 +2,11 @@
<navigation 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/mobile_navigation"
app:startDestination="@+id/navigation_home">
android:id="@+id/navigation_dashboard"
app:startDestination="@id/DashboardFragment">

<fragment
android:id="@+id/navigation_home"
android:name="com.aaglobal.jnc_playground.ui.home.HomeFragment"
android:label="@string/title_home"
tools:layout="@layout/fragment_home" />

<fragment
android:id="@+id/navigation_dashboard"
android:id="@+id/DashboardFragment"
android:name="com.aaglobal.jnc_playground.ui.dashboard.DashboardFragment"
android:label="@string/title_dashboard"
tools:layout="@layout/fragment_dashboard">
Expand All @@ -23,12 +17,6 @@

</fragment>

<fragment
android:id="@+id/navigation_notifications"
android:name="com.aaglobal.jnc_playground.ui.notifications.NotificationsFragment"
android:label="@string/title_notifications"
tools:layout="@layout/fragment_notifications" />

<fragment
android:id="@+id/GraphicFragment"
android:name="com.aaglobal.jnc_playground.ui.graphic.GraphicFragment"
Expand Down

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