java - 如何在导航组件中从子片段中关闭父片段
问题描述
我正在创建一个需要嵌套导航图并希望从子片段中关闭父片段的应用程序。
我可以通过调用来关闭一个片段,
getActivity().getSupportFragmentManager().popBackStack();
我只能关闭返回堆栈中的当前顶部片段。
在这张图片中,我想从 Fragment3 关闭 Fragment2。
编辑:
我正在打开 Fragment2:
Navigation.findNavController(getView()).navigate(R.id.action_fragment1_to_fragment2);
片段1:
public class Fragment1 extends Fragment {
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment1, container, false);
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
getView().findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Navigation.findNavController(v).navigate(R.id.action_fragment1_to_fragment2);
}
});
}
}
片段1布局:
<?xml version="1.0" encoding="utf-8"?>
<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:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/colorPrimaryDark">
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
框架2:
public class Fragment2 extends Fragment {
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment2, container, false);
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
public void close () {
getActivity().getSupportFragmentManager().popBackStack();
}
}
在 Fragment2 我有另一个图, Fragment2 布局:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<fragment
android:id="@+id/child_graph_base"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:defaultNavHost="true"
app:navGraph="@navigation/child_graph" />
</android.support.constraint.ConstraintLayout>
片段3:
public class Fragment3 extends Fragment {
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment3, container, false);
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
getView().findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
NavHostFragment navHostFragment = (NavHostFragment) getParentFragment();
Fragment2 fragment2 = (Fragment2) navHostFragment.getParentFragment();
fragment2.close();
}
});
}
}
片段3布局:
<?xml version="1.0" encoding="utf-8"?>
<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:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/colorPrimaryDark">
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
<?xml version="1.0" encoding="utf-8"?>
<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/main_graph"
app:startDestination="@id/fragment1">
<fragment
android:id="@+id/fragment1"
android:name="alistar.navigation.fragments.Fragment1"
android:label="fragment1"
tools:layout="@layout/fragment1" >
<action
android:id="@+id/action_fragment1_to_fragment2"
app:destination="@id/fragment2" />
</fragment>
<fragment
android:id="@+id/fragment2"
android:name="alistar.navigation.fragments.Fragment2"
android:label="fragment2"
tools:layout="@layout/fragment2" />
</navigation>
子图(在 Framgent2 中)
<?xml version="1.0" encoding="utf-8"?>
<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/child_graph"
app:startDestination="@id/fragment3">
<fragment
android:id="@+id/fragment3"
android:name="alistar.navigation.fragments.Fragment3"
android:label="fragment3"
tools:layout="@layout/fragment3" />
</navigation>
解决方案
我通过从 Fragment3 调用close()
父片段(Fragment2)中的方法解决了这个问题。我将关闭方法更改为:
public void close () {
Navigation.findNavController(getView()).popBackStack();
}
我也删除了:
app:defaultNavHost="true"
从我的孩子图中,工作正常!
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