Android:通过查找带有标签而不是ID的容器来添加片段 [英] Android: Add fragments by looking up container with tag instead of ID

问题描述

我正在使用for循环创建片段的多个实例.在每个片段中，我需要添加另一组子片段.为此，我需要找到正确的容器.如果使用容器的ID，则所有子片段都将添加到第一个父片段中，而不是它们自己的父片段中.

在我的主要片段中:

<.> <代码>用于(....){ParentFragment parentFragment = new ParentFragment();parentFragment.setSomeData(data);fragmentTransaction.add(R.id.main_fragment_container，parentFragment，data);}fragmentTransaction.commit();

现在我有N个父片段.

在每个ParentFragment中:

  @Overridepublic void onViewCreated(@NonNull View view，@Nullable Bundle savedInstanceState){ChildFragment childFragment = new ChildFragment();childFragment.setSomeData(data);fragmentTransaction.add(R.id.parent_fragment_container，childFragment).commit();} 

问题是， ChildFragment 的所有实例都添加到第一个ParentFragment中，因为"R.id.parent_fragment_container"是所有ParentFragment的常量.对于ParentFragment的每个实例，它都不会更改.

因为我对ParentFragment的每个实例都有唯一的标签，我可以使用此标签而不是 R.id.parent_fragment_container 来查找容器吗?

XML定义:

fragment_main.xml:

 < LinearLayoutandroid:id ="@ + id/main_fragment_container"android:layout_width ="match_parent"android:layout_height ="wrap_content"android:orientation ="vertical"></LinearLayout> 

fragment_parent.xml:

 <?xml version ="1.0" encoding ="utf-8"?>< LinearLayout xmlns:android ="http://schemas.android.com/apk/res/android"android:id ="@ + id/parent_fragment_container"android:layout_width ="match_parent"android:layout_height ="wrap_content"android:orientation ="vertical"></LinearLayout> 

解决方案

Fragment 在另一个 Fragment 中应该与该父 Fragment 处理的 FragmentManager –通过 getChildFragmentManager()获得–而不是 Activity 的 FragmentManager .

子级 FragmentManager 将仅搜索父级 Fragment 的 View 以获取给定的容器ID，因此最终不会所有第一个找到的容器中的子 Fragment 子元素，例如 Activity 的 FragmentManager 刚使用第一个 parent_fragment_container时发生的情况会在 Activity 的整体层次结构中找到.

I am creating multiple instances of a fragment with a for loop. Within each fragment, I need to add another set of child fragments. In doing that, I need to find the correct container. If I use the ID of the container, all the child fragments gets added to the first parent fragment, instead of their own parent fragments.

In my main fragment:

for (....) {
    ParentFragment parentFragment = new ParentFragment();
    parentFragment.setSomeData(data);
    fragmentTransaction.add(R.id.main_fragment_container, parentFragment, data);
}

fragmentTransaction.commit();

Now I have N Parent Fragments.

Within each ParentFragment:

@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
    ChildFragment childFragment = new ChildFragment();
    childFragment.setSomeData(data);
    fragmentTransaction.add(R.id.parent_fragment_container, childFragment).commit();
}

The issue is, all instances of ChildFragment gets added to the first ParentFragment because "R.id.parent_fragment_container" is a constant for all ParentFragment. It doesn't change for each instance of ParentFragment.

Because I have unique tag for each instance of ParentFragment, can I lookup the container using this tag instead of R.id.parent_fragment_container?

XML definitions:

fragment_main.xml:

<LinearLayout
    android:id="@+id/main_fragment_container"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

</LinearLayout>

fragment_parent.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/parent_fragment_container"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical">

</LinearLayout>

解决方案

Fragments inside another Fragment should be handled with that parent Fragment's FragmentManager – obtained with getChildFragmentManager() – rather than the Activity's FragmentManager.

The child FragmentManager will search only the parent Fragment's View for the given container ID, so you won't end up with all of the child Fragments in the first found container, as was happening when the Activity's FragmentManager just used the first parent_fragment_container it would find in the Activity's overall hierarchy.

这篇关于Android:通过查找带有标签而不是ID的容器来添加片段的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！