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Last active Nov 28, 2021
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<?xml version="1.0" encoding="utf-8"?> | |
<resources> | |
<declare-styleable name="DialogNavigator"> | |
<attr name="android:name"/> | |
</declare-styleable> | |
</resources> |
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package com.geekorum.geekdroid.navigation | |
import android.content.Context | |
import android.os.Bundle | |
import android.util.AttributeSet | |
import androidx.core.content.res.use | |
import androidx.core.os.bundleOf | |
import androidx.fragment.app.DialogFragment | |
import androidx.fragment.app.Fragment | |
import androidx.fragment.app.FragmentManager | |
import androidx.navigation.NavDestination | |
import androidx.navigation.NavOptions | |
import androidx.navigation.Navigator | |
import androidx.navigation.fragment.FragmentNavigator | |
import androidx.navigation.fragment.NavHostFragment | |
import androidx.navigation.plusAssign | |
import com.geekorum.geekdroid.R | |
import java.util.ArrayDeque | |
import java.util.Deque | |
/** | |
* Allows to navigate to some [DialogFragment]. | |
* | |
* Usage: add some dialog element in your navigation graph | |
* ``` | |
* <dialog android:id="@+id/my_dialog" | |
* android:name="com.exemple.MyDialogFragment"/> | |
* | |
* ``` | |
* Use [DialogNavHostFragment] as your [androidx.navigation.NavHost] in your layout | |
* or add the DialogNavigator to your [NavigatorProvider] | |
*/ | |
@Navigator.Name("dialog") | |
class DialogNavigator( | |
private val context: Context, | |
private val fragmentManager: FragmentManager | |
) : Navigator<DialogNavigator.Destination>() { | |
private var lastBackStackEntry: FragmentManager.BackStackEntry? = null | |
private val backstack: Deque<Int> = ArrayDeque() | |
private var pendingPopBackStack = false | |
private val onBackstackChangedListener: FragmentManager.OnBackStackChangedListener = | |
FragmentManager.OnBackStackChangedListener { | |
if (pendingPopBackStack) { | |
val entry = fragmentManager.findLastBackStackEntry { it.name == FRAGMENT_BACKSTACK_NAME } | |
pendingPopBackStack = (entry != null && entry == lastBackStackEntry) | |
lastBackStackEntry = entry | |
return@OnBackStackChangedListener | |
} | |
if (lastBackStackEntry != null && fragmentManager.noneBackStackEntry { it == lastBackStackEntry }) { | |
backstack.removeLast() | |
} | |
lastBackStackEntry = fragmentManager.findLastBackStackEntry { it.name == FRAGMENT_BACKSTACK_NAME } | |
} | |
override fun navigate( | |
destination: Destination, args: Bundle?, navOptions: NavOptions?, navigatorExtras: Extras? | |
): NavDestination? { | |
val lastDialogFragment = instantiateFragment(destination.className!!, args) | |
val tr = fragmentManager.beginTransaction().addToBackStack(FRAGMENT_BACKSTACK_NAME) | |
lastDialogFragment.show(tr, destination.id.toString()) | |
backstack.addLast(destination.id) | |
// we don't want the destination to be added to the NavController stack, | |
// because it will update the whole | |
// navigation chrome (global AppBar, NavigationView, etc) | |
return null | |
} | |
private fun instantiateFragment(className: String, args: Bundle?): DialogFragment { | |
return Fragment.instantiate(context, className, args) as DialogFragment | |
} | |
override fun createDestination(): Destination = Destination(this) | |
override fun popBackStack(): Boolean { | |
val lastDialogFragment = | |
fragmentManager.findFragmentByTag(backstack.lastOrNull()?.toString()) as? DialogFragment ?: return false | |
lastDialogFragment.dismiss() | |
backstack.removeLast() | |
pendingPopBackStack = true | |
return true | |
} | |
/* These 2 lifecycle methods should be handled in the NavHost of this navigator. | |
* When the NavHost add them it should configure them or call some method so | |
* that they can configure there listeners. However, this make a strong coupling between a Navigator and | |
* its host implementation. | |
* | |
* The NavigatorProvider of NavController add a Navigator.OnBackStackChangedListener | |
* who calls these methods */ | |
override fun onBackPressAdded() { | |
fragmentManager.addOnBackStackChangedListener(onBackstackChangedListener) | |
} | |
override fun onBackPressRemoved() { | |
fragmentManager.removeOnBackStackChangedListener(onBackstackChangedListener) | |
} | |
override fun onSaveState(): Bundle? { | |
return bundleOf(KEY_BACKSTACK_ID to backstack.toIntArray()) | |
} | |
override fun onRestoreState(savedState: Bundle) { | |
savedState.getIntArray(KEY_BACKSTACK_ID)?.let { | |
backstack.clear() | |
for (id in it) { | |
backstack.addLast(id) | |
} | |
} | |
lastBackStackEntry = fragmentManager.findLastBackStackEntry { it.name == FRAGMENT_BACKSTACK_NAME } | |
} | |
class Destination(navigator: DialogNavigator) : NavDestination(navigator) { | |
var className: String? = null | |
get() = checkNotNull(field) { "Dialog name was not set" } | |
override fun onInflate(context: Context, attrs: AttributeSet) { | |
super.onInflate(context, attrs) | |
context.resources.obtainAttributes(attrs, R.styleable.DialogNavigator).use { | |
className = it.getString(R.styleable.DialogNavigator_android_name) | |
} | |
} | |
} | |
companion object { | |
private const val KEY_BACKSTACK_ID = "com.geekorum.geekdroid:navigation:backstack_ids" | |
private const val FRAGMENT_BACKSTACK_NAME = "com.geekorum.geekdroid:navigation:backstack" | |
} | |
private inline fun FragmentManager.findLastBackStackEntry( | |
predicate: (FragmentManager.BackStackEntry) -> Boolean | |
): FragmentManager.BackStackEntry? { | |
for (i in backStackEntryCount - 1 downTo 0) { | |
val backStackEntry = getBackStackEntryAt(i) | |
if (predicate(backStackEntry)) { | |
return backStackEntry | |
} | |
} | |
return null | |
} | |
private inline fun FragmentManager.noneBackStackEntry( | |
predicate: (FragmentManager.BackStackEntry) -> Boolean | |
): Boolean { | |
for (i in 0 until backStackEntryCount) { | |
val backStackEntry = getBackStackEntryAt(i) | |
if (predicate(backStackEntry)) { | |
return false | |
} | |
} | |
return true | |
} | |
} | |
/** | |
* A [NavHostFragment] who supports navigation to [DialogFragment]. | |
*/ | |
class DialogNavHostFragment : NavHostFragment() { | |
override fun createFragmentNavigator(): Navigator<out FragmentNavigator.Destination> { | |
navController.navigatorProvider += DialogNavigator(requireContext(), childFragmentManager) | |
return super.createFragmentNavigator() | |
} | |
} |
In future, we can use <dialog>
NavDestination at 2.1.0-alpha03
version, maybe.
https://android-review.googlesource.com/c/platform/frameworks/support/+/949238
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I suggest to change the current implementation of
instantiateFragment
method from this:to this:
Because starting from navigation
2.1.0-alpha01
they have moved into usingFragmentFactory
to create Fragments insideFragmentNavigator
so we should move to use the same API to support FragmentFactory user. Default users will not notice any difference.Source: https://issuetracker.google.com/issues/119054429
Btw I've forked your gist and made some changes to work with
2.1.0-alpha01
version