Android Backstack 与 Nested/Child 碎片

Question

我对嵌套 Fragment 的回栈方式有疑问，如果能提供任何帮助，我将不胜感激。

我有片段 A 和片段 B。片段 A 包含另一个片段 (ButtonFragment)。在 Activity 的 onCreate 中，我加载片段 A，然后切换到片段 B。当我返回片段 A（从后台堆栈中取出）时，出现以下错误。

Exception dispatching finished signal.

E/MessageQueue-JNI(6330): Exception in MessageQueue callback: handleReceiveCallback

E/MessageQueue-JNI(6330): android.view.InflateException: Binary XML file line #16: Error inflating class fragment

...

Caused by: java.lang.IllegalArgumentException: Binary XML file line 16: Duplicate id 0x7f080000, tag null, or parent id 0x0 with another fragment for com.example.fragmentnavigation.MainActivity$ButtonFragment

没有子片段导航工作。也许我必须添加一些 ChildFragmentManager 处理，但我不知道是什么以及在哪里。我希望你能帮助我。

主布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<Button
    android:id="@+id/button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/app_name" />

<FrameLayout 
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    tools:context="com.example.fragmentnavigation.MainActivity"
    tools:ignore="MergeRootFrame" />
</LinearLayout>

片段布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.fragmentnavigation.MainActivity$FragmentA" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <fragment 
        android:id="@+id/button"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:name="com.example.fragmentnavigation.MainActivity$ButtonFragment"/> 

</LinearLayout>

MainAcitivity

public class MainActivity extends FragmentActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    if (savedInstanceState == null) {
        getSupportFragmentManager().beginTransaction()
                .add(R.id.container, new FragmentA()).commit();
    }
}
...
private void switchToB() {
    FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
    ft.replace(R.id.container, new BFragment());
    ft.addToBackStack(null);
    ft.commit();
}

片段A

public static class FragmentA extends Fragment {

        public FragmentA() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container,
                    false);
            return rootView;
        }
    }

按钮片段

public static class ButtonFragment extends Fragment {

        public ButtonFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.buttonfragment, container,
                    false);
            return rootView;
        }
    }

解决方案 特别感谢@arun-kumar

关于片段的非常好的概述 https://github.com/codepath/android_guides/wiki/Creating-and-Using-Fragments

片段布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.fragmentnavigation.MainActivity$FragmentA" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <FrameLayout
        android:id="@+id/child_fragment_container"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />

</LinearLayout>

onCreate 片段 A

@Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container,
                    false);

            Fragment childFragment = new ButtonFragment();
            FragmentTransaction transaction = getChildFragmentManager().beginTransaction();
            transaction.replace(R.id.child_fragment_container, childFragment).commit();

            return rootView;
        }

Answer 1

我认为此异常背后的原因是您的视图中有两个视图元素 id=@+id/button

<Button
    android:id="@+id/button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="@string/app_name" />

和

<fragment 
        android:id="@+id/button"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:name="com.example.fragmentnavigation.MainActivity$ButtonFragment"/>

尝试将其中一个重命名为唯一的名称

Answer 2

您必须在运行时添加子片段，而不是在 Fragment A 布局文件中的布局中声明它。我在实施 google 地图时遇到了同样的问题。

Answer 3

Caused by: java.lang.IllegalArgumentException: Binary XML file line 16: Duplicate id 0x7f080000, tag null, or parent id 0x0 with another fragment for com.example.fragmentnavigation.MainActivity$ButtonFragment

您布局中的两个控件具有相同的id，您需要更改其中任何一个控件的id

Android Backstack 与 Nested/Child 碎片

Android Backstack with Nested/Child Fragments

navigation

android

android-fragments

android-nested-fragment

fragment-backstack