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il...@google.com
ma...@gmail.com
I'd like to add that this automatic removal of the NavGraph at the top of the stack is also making it hard for me to implement proper lateral top-level navigation.
A practical case where this kind of navigation happens is with a Material Design bottom navigation bar, where I have a NavHost above the bottom bar.
Given this navigation scheme:
A - B (top-level)
B1 (first sub-level)
When starting the Activity, the back stack is
0. A
1. NavGraph
If I wanted to navigate to B laterally, I would do:
navController.popBackStack(R.id.navGraph, false)
navController.navigate(R.id.B)
But the resulting back stack is:
0. B
Now, navigating between top-level destinations actually works (though popBackStack returns false); the problem arises again if I navigate to B1:
0. B1
1. B
When navigating from B1 to a top-level destination like A, the stack becomes:
0. A
1. B1
2. B
That is, A is not a top-level destination in the back stack: if I press back from A, I intend to exit the app, but I'm taken back to B1.
It would be nice to have a fixed reference to the bottom of the stack. Right now I'm working around this with a horrible ` while (navController.popBackStack()) continue`.
A practical case where this kind of navigation happens is with a Material Design bottom navigation bar, where I have a NavHost above the bottom bar.
Given this navigation scheme:
A - B (top-level)
B1 (first sub-level)
When starting the Activity, the back stack is
0. A
1. NavGraph
If I wanted to navigate to B laterally, I would do:
navController.popBackStack(R.id.navGraph, false)
navController.navigate(R.id.B)
But the resulting back stack is:
0. B
Now, navigating between top-level destinations actually works (though popBackStack returns false); the problem arises again if I navigate to B1:
0. B1
1. B
When navigating from B1 to a top-level destination like A, the stack becomes:
0. A
1. B1
2. B
That is, A is not a top-level destination in the back stack: if I press back from A, I intend to exit the app, but I'm taken back to B1.
It would be nice to have a fixed reference to the bottom of the stack. Right now I'm working around this with a horrible ` while (navController.popBackStack()) continue`.
ch...@moqi.co.uk
Is this going to be fixed?
I have the same issue with a setup as follows:
Navigation graph.
<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 "
app:startDestination="@+id/startupGraph">
<navigation
android:id="@+id/startupGraph"
app:startDestination="@id/launcher_home">
<fragment
android:id="@+id/launcher_home"
android:name="com.example.android.codelabs.navigation.MainFragment"
android:label="@string/home"
tools:layout="@layout/main_fragment" />
</navigation>
<navigation
android:id="@+id/homeGraph"
app:startDestination="@id/flow_step_one">
<fragment
android:id="@+id/flow_step_one"
android:name="com.example.android.codelabs.navigation.FlowStepOneFragment"
tools:layout="@layout/flow_step_one_fragment" />
<fragment
android:id="@+id/flow_step_two"
android:name="com.example.android.codelabs.navigation.FlowStepTwoFragment"
tools:layout="@layout/flow_step_two_fragment" />
</navigation>
</navigation>
MainFragment.
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
view.findViewById<Button>(R.id.navigate_dest_bt).setOnClickListener{
Navigation.findNavController(it)
.navigate(R.id.homeGraph, null, NavOptions.Builder()
.setPopUpTo(R.id.startupGraph, false)
.build())
}
}
FlowStepOneFragment.
view.findViewById<View>(R.id.next_button).setOnClickListener {
Navigation.findNavController(it)
.navigate(R.id.flow_step_two, null, NavOptions.Builder()
.setPopUpTo(R.id.flow_step_one, true)
.build())
}
}
}
Causes the following error:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.android.codelabs.navigation, PID: 12579
java.lang.IllegalArgumentException: Navigator androidx.navigation.fragment.FragmentNavigator@d70ec6f reported navigation to unknown destination id com.example.android.codelabs.navigation:id/flow_step_two
I have the same issue with a setup as follows:
Navigation graph.
<navigation xmlns:android="
xmlns:app="
xmlns:tools="
app:startDestination="@+id/startupGraph">
<navigation
android:id="@+id/startupGraph"
app:startDestination="@id/launcher_home">
<fragment
android:id="@+id/launcher_home"
android:name="com.example.android.codelabs.navigation.MainFragment"
android:label="@string/home"
tools:layout="@layout/main_fragment" />
</navigation>
<navigation
android:id="@+id/homeGraph"
app:startDestination="@id/flow_step_one">
<fragment
android:id="@+id/flow_step_one"
android:name="com.example.android.codelabs.navigation.FlowStepOneFragment"
tools:layout="@layout/flow_step_one_fragment" />
<fragment
android:id="@+id/flow_step_two"
android:name="com.example.android.codelabs.navigation.FlowStepTwoFragment"
tools:layout="@layout/flow_step_two_fragment" />
</navigation>
</navigation>
MainFragment.
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
view.findViewById<Button>(R.id.navigate_dest_bt).setOnClickListener{
Navigation.findNavController(it)
.navigate(R.id.homeGraph, null, NavOptions.Builder()
.setPopUpTo(R.id.startupGraph, false)
.build())
}
}
FlowStepOneFragment.
view.findViewById<View>(R.id.next_button).setOnClickListener {
Navigation.findNavController(it)
.navigate(R.id.flow_step_two, null, NavOptions.Builder()
.setPopUpTo(R.id.flow_step_one, true)
.build())
}
}
}
Causes the following error:
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.android.codelabs.navigation, PID: 12579
java.lang.IllegalArgumentException: Navigator androidx.navigation.fragment.FragmentNavigator@d70ec6f reported navigation to unknown destination id com.example.android.codelabs.navigation:id/flow_step_two
il...@google.com
The original issue was fixed as a result of https://android-review.googlesource.com/833717 and a number of other internal changes and that will be available in alpha08.
Discovered another issue when doing this specific set of navigation actions, so leaving this open until that part is also fixed.
Discovered another issue when doing this specific set of navigation actions, so leaving this open until that part is also fixed.
ap...@google.com
Project: platform/frameworks/support
Branch: androidx-master-dev
commit d3507cb9dab82264070c72a37dbde1dfb43ef578
Author: Ian Lake <ilake@google.com>
Date: Tue Dec 04 14:24:32 2018
Split pop and dispatch logic
When using popUpTo, navigate() would
internally call popBackStack(), resulting
in additional dispatch calls to
OnDestinationChangedListener before the
navigate() operation itself was done.
By separating the logic, we can ensure that
we don't prematurely remove NavGraph destinations
that should still exist after the navigate()
operation and that developers only see a
single final OnDestinationChangedListener callback.
Test: new test
BUG: 113611083
Change-Id: Ib63e4156521259a945ffecf679ccb404ac192017
M navigation/runtime/src/androidTest/java/androidx/navigation/NavControllerTest.kt
M navigation/runtime/src/androidTest/res/navigation/nav_nested_start_destination.xml
M navigation/runtime/src/main/java/androidx/navigation/NavController.java
https://android-review.googlesource.com/840996
https://goto.google.com/android-sha1/d3507cb9dab82264070c72a37dbde1dfb43ef578
Branch: androidx-master-dev
commit d3507cb9dab82264070c72a37dbde1dfb43ef578
Author: Ian Lake <ilake@google.com>
Date: Tue Dec 04 14:24:32 2018
Split pop and dispatch logic
When using popUpTo, navigate() would
internally call popBackStack(), resulting
in additional dispatch calls to
OnDestinationChangedListener before the
navigate() operation itself was done.
By separating the logic, we can ensure that
we don't prematurely remove NavGraph destinations
that should still exist after the navigate()
operation and that developers only see a
single final OnDestinationChangedListener callback.
Test: new test
BUG: 113611083
Change-Id: Ib63e4156521259a945ffecf679ccb404ac192017
M navigation/runtime/src/androidTest/java/androidx/navigation/NavControllerTest.kt
M navigation/runtime/src/androidTest/res/navigation/nav_nested_start_destination.xml
M navigation/runtime/src/main/java/androidx/navigation/NavController.java
Description
android.arch.navigation:navigation-fragment-ktx
android.arch.navigation:navigation-ui-ktx
Version used:
1.0.0-alpha05
Devices/Android versions reproduced on:
-SM-A510F, Android 7.0
-Emulator x86_64 API 28
Sample project:
Description:
Having this structure:
nav_graph.xml
<navigation
android:id="@+id/nav_graph"
app:startDestination="@id/startFragment">
<fragment
android:id="@+id/startFragment"
android:name="com.example.navbug.StartFragment"
android:label="StartFragment"
tools:layout="@layout/fragment_start">
<action
android:id="@+id/action_startFragment_to_nested_nav_graph"
app:destination="@id/nested_nav_graph" />
</fragment>
<include app:graph="@navigation/nested_nav_graph" />
</navigation>
nested_nav_graph.xml
<navigation
android:id="@+id/nested_nav_graph"
app:startDestination="@id/nestedStartFragment">
<fragment
android:id="@+id/nestedStartFragment"
android:name="com.example.navbug.NestedStartFragment"
android:label="NestedStartFragment">
<action
android:id="@+id/action_nestedStartFragment_to_nestedSecondFragment"
app:destination="@id/nestedSecondFragment"
app:popUpTo="@+id/nestedStartFragment"
app:popUpToInclusive="true" />
</fragment>
<fragment
android:id="@+id/nestedSecondFragment"
android:name="com.example.navbug.NestedSecondFragment"
android:label="NestedSecondFragment" />
</navigation>
I want to achieve this navigation pattern:
StartFragment => NestedStartFragment => NestedSecondFragment =(back)=> StartFragment
I'm trying to implement this by setting the action NestedStartFragment=>NestedSecondFragment with the options [popUpTo=NestedStartFragment, popUpToInclusive=true], so that the resulting stack would be:
0. NestedSecondFragment
1. NestedNavGraph
2. StartFragment
3. NavGraph
When navigating from NestedStartFragment to NestedSecondFragment, the following execption occurs:
java.lang.IllegalArgumentException: Navigator androidx.navigation.fragment.FragmentNavigator@ccc9092 reported navigation to unknown destination id com.example.navbug:id/nestedSecondFragment
at androidx.navigation.NavController$2.onNavigatorNavigated(NavController.java:142)
at androidx.navigation.Navigator.dispatchOnNavigatorNavigated(Navigator.java:217)
at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.java:207)
at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.java:45)
at androidx.navigation.NavDestination.navigate(NavDestination.java:407)
at androidx.navigation.NavController.navigate(NavController.java:683)
at androidx.navigation.NavController.navigate(NavController.java:630)
at androidx.navigation.NavController.navigate(NavController.java:618)
at com.example.navbug.NestedStartFragment$onViewCreated$1.onClick(Fragments.kt:31)
at android.view.View.performClick(View.java:6597)
at android.view.View.performClickInternal(View.java:6574)
at android.view.View.access$3100(View.java:778)
at android.view.View$PerformClick.run(View.java:25885)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Right before the navigation, the stack is:
0. NestedStartFragment
1. NestedNavGraph
2. StartFragment
3. NavGraph
When NestedStartFragment is popped on my request, NestedNavGraph is also popped because
"// We never want to leave NavGraphs on the top of the stack" (from NavController.onNavigatorNavigated)
with the effect that eventually the requested destination NestedSecondFragment is pruned from the graph and cannot be reached anymore.
Unless I'm doing something wrong, it seems that NavGraph automatic popping should be avoided if the final destination actually belongs to it.