列表项单击时 ListFragment 不会替换 ListFragment

Posted 2023-04-18

【中文标题】列表项单击时 ListFragment 不会替换 ListFragment

【英文标题】：ListFragment won't replace ListFragment when list item click

【发布时间】：2017-07-23 20:47:03

【问题描述】：

我正在开发一个具有显示 ListFragment 的 FragmentPagerAdapter 的应用程序。如果用户单击列表中的某个项目，我将尝试执行 FragmentTransaction 并将当前 Fragment 替换为下一个。

但是，当我尝试在 onItemClick 中切换片段时，没有任何反应，没有错误，但列表片段没有改变。我附上了我目前正在尝试的相关代码。我认为这是因为我使用了错误的 fragmentManager，但我不确定如何获得正确的。

---

一个 FragmentPagerAdapter，它返回一个对应于应用程序主要部分之一的片段。

public static class AppSectionsPagerAdapter extends FragmentPagerAdapter 

    public AppSectionsPagerAdapter(FragmentManager fm) 
        super(fm);
    

    @Override
    public Fragment getItem(int i) 
        switch (i) 
            case 0:
                // The first section of the app is the most interesting -- it offers
                // a launchpad into the other demonstrations in this example application.
                return new LaunchpadSectionFragment();

            case 1:
                return new LibrarySectionFragment();

            case 2:
                return new LipshapeSectionFragment();


            default:
                // The other sections of the app are dummy placeholders.
                Fragment fragment = new DummySectionFragment();
                Bundle args = new Bundle();
                args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, i + 1);
                fragment.setArguments(args);
                return fragment;
        
    

    @Override
    public int getCount() 
        return 3;
    

    @Override
    public CharSequence getPageTitle(int position)
    
        switch (position)
        
            case 0:
                return "Practice";
            case 1:
                return "Library";
            case 2:
                return "Help";
        

        return "Untitled";
    

这是具有 onClick 的 ListFragment

public static class LipshapeSectionFragment extends ListFragment implements AdapterView.OnItemClickListener


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

        return rootView;
    

    @Override
    public void onActivityCreated(Bundle savedInstanceState) 
        super.onActivityCreated(savedInstanceState);

        ContentResolver resolver = this.getContext().getContentResolver();

        //  if you only want one column do it like this
        // String[] projection = new String[]BaseColumns._ID, VideoFilesContract.videoFiles.FILENAME;
        Cursor lipshapeCursor =
                resolver.query(LipshapeContract.lipshapes.CONTENT_URI,
                        LipshapeContract.lipshapes.PROJECTION_ALL,
                        null,
                        null,
                        null);

        lipshapeCursor.moveToFirst();

        // Setup cursor adapter using cursor from last step
        LipshapeCursorAdapter lipshapeAdapter = new LipshapeCursorAdapter(this.getContext(), lipshapeCursor);
        // Attach cursor adapter to the ListView

        setListAdapter(lipshapeAdapter);
        getListView().setOnItemClickListener(this);
    

    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position,long id)
    
        Cursor cursor  = ((Cursor) getListView().getItemAtPosition(position));

        ContentResolver resolver = this.getContext().getContentResolver();

        Cursor wordCursor =
                resolver.query(WordContract.wordItems.CONTENT_URI,
                        WordContract.wordItems.PROJECTION_ALL,
                        "lipshape_id=?",
                        new String[]cursor.getString(cursor.getColumnIndex("_id")),
                        null);

        int count = wordCursor.getCount();

        TestSectionFragment fragment = new TestSectionFragment();

        FragmentManager fragmentManager = getChildFragmentManager();
        fragmentManager.beginTransaction().replace(R.id.lvLibrary, fragment).addToBackStack(null).commit();

        //Toast.makeText(getActivity(), "Words within this group: " + count, Toast.LENGTH_SHORT).show();
    

ListFragment 的布局文件（fragment_section_library）：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/lvLibrary"
android:layout_
android:layout_>
<ListView
android:id="@android:id/list"
android:layout_
android:layout_ />
</LinearLayout>

我正在尝试将 ListFragment 替换为的测试片段：

 */
public static class TestSectionFragment extends Fragment 

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) 
        View rootView = inflater.inflate(R.layout.fragment_section_dummy, container, false);
        Bundle args = getArguments();
        ((TextView) rootView.findViewById(android.R.id.text1)).setText(
                "Test Worked");
        return rootView;
    

TestFragment 的布局文件（fragment_section_dummy）：

<TextView xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@android:id/text1"
android:layout_
android:layout_
android:gravity="center"
android:textSize="24sp"
android:padding="32dp" />

【参考方案1】：

我已经设法找到了问题所在。主要问题是您必须先以编程方式添加片段，然后才能替换它，这是解决问题所需的更改，它显示了一个列表视图，该列表视图在 listItem 单击时被另一个列表视图替换：

/**
     * A lipshape list fragment
     */
    public static class LipshapeSectionFragment extends ListFragment implements AdapterView.OnItemClickListener, LoaderManager.LoaderCallbacks<Cursor>
    

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

        return rootView;
    

    @Override
    public void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);

        ContentResolver resolver = this.getContext().getContentResolver();

        //  if you only want one column do it like this
        // String[] projection = new String[]BaseColumns._ID, VideoFilesContract.videoFiles.FILENAME;
        Cursor lipshapeCursor =
                resolver.query(LipshapeContract.lipshapes.CONTENT_URI,
                        LipshapeContract.lipshapes.PROJECTION_ALL,
                        null,
                        null,
                        null);


        // Setup cursor adapter using cursor from last step
        lipshapeAdapter = new LipshapeCursorAdapter(this.getContext(), lipshapeCursor);
        // Attach cursor adapter to the ListView

        //setListAdapter(lipshapeAdapter);
        //getListView().setOnItemClickListener(this);
    

    @Override
    public void onActivityCreated(Bundle savedInstanceState) 
        super.onActivityCreated(savedInstanceState);
    

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) 
        super.onViewCreated(view, savedInstanceState);

        setListAdapter(lipshapeAdapter);
        getListView().setOnItemClickListener(this);
    

    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position,long id)
    
        Cursor cursor  = ((Cursor) getListView().getItemAtPosition(position));

        ContentResolver resolver = this.getContext().getContentResolver();

        Cursor wordCursor =
                resolver.query(WordContract.wordItems.CONTENT_URI,
                        WordContract.wordItems.PROJECTION_ALL,
                        "lipshape_id=?",
                        new String[]cursor.getString(cursor.getColumnIndex("_id")),
                        null);

        int count = wordCursor.getCount();

        WordListSectionFragment fragment = new WordListSectionFragment();

        Bundle args = new Bundle();

        args.putString("lipshape_selected", cursor.getString(cursor.getColumnIndex("_id")));
        fragment.setArguments(args);

        FragmentManager fragmentManager = getFragmentManager();
        fragmentManager.beginTransaction().replace(R.id.svBody, fragment).addToBackStack(null).commit();


        //Toast.makeText(getActivity(), "Words within this group: " + count, Toast.LENGTH_SHORT).show();
    

    @Override
    public Loader<Cursor> onCreateLoader(int i, Bundle bundle) 
        return null;
    

    @Override
    public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) 

    

    @Override
    public void onLoaderReset(Loader<Cursor> loader) 

    

单词列表片段

    /**
     * 
     * WordListFragment
     */
    public static class WordListSectionFragment extends ListFragment implements AdapterView.OnItemClickListener, LoaderManager.LoaderCallbacks<Cursor> 

        public static final String ARG_SECTION_NUMBER = "section_number";

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

            return rootView;
        

        @Override
        public void onActivityCreated(Bundle savedInstanceState) 
            super.onActivityCreated(savedInstanceState);

            ContentResolver resolver = getContext().getContentResolver();

            Bundle args = getArguments();

            Cursor wordCursor =
                    resolver.query(WordContract.wordItems.CONTENT_URI,
                            WordContract.wordItems.PROJECTION_ALL,
                            "lipshape_id=?",
                            new String[]args.getString("lipshape_selected"),
                            null);

            wordCursor.moveToFirst();

            // Setup cursor adapter using cursor from last step
            WordCursorAdapter wordAdapter = new WordCursorAdapter(this.getContext(), wordCursor);
            // Attach cursor adapter to the ListView
            setListAdapter(wordAdapter);
            getListView().setOnItemClickListener(this);

        

            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int position,long id)
            
                Cursor cursor  = ((Cursor) getListView().getItemAtPosition(position));

                String test = cursor.getString(cursor.getColumnIndex("description"));
                int word_id = cursor.getInt(cursor.getColumnIndex("_id"));

                Intent intent = new Intent(getActivity(), CollectionDemoActivity.class);
                intent.putExtra("word_id", word_id);
                startActivity(intent);

        

        @Override
        public Loader<Cursor> onCreateLoader(int i, Bundle bundle) 
            return null;
        

        @Override
        public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) 

        

        @Override
        public void onLoaderReset(Loader<Cursor> loader) 

        
    

LibrarySectionFragment

    /**
     *
     * A library fragment
     */
    public static class LibrarySectionFragment extends Fragment 

        @Override
        public void onActivityCreated(@Nullable Bundle savedInstanceState) 

            LipshapeSectionFragment fragment = new LipshapeSectionFragment();

            FragmentManager fragmentManager = getFragmentManager();
            fragmentManager.beginTransaction().add(R.id.svBody, fragment).commit();

            super.onActivityCreated(savedInstanceState);
        

        @Override
        public void onCreate(@Nullable Bundle savedInstanceState) 

            super.onCreate(savedInstanceState);
        

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) 

            View rootView = inflater.inflate(R.layout.fragment_section_dummy, container, false);
            Bundle args = getArguments();

            return rootView;
        
    

主要变化来自第一个列表片段：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/lvLibrary"
    android:layout_
    android:layout_>
<ListView
    android:id="@android:id/list"
    android:layout_
    android:layout_ />
</LinearLayout>

接下来我们有它所在的基础片段：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/svBody"
    android:layout_
    android:layout_
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin">

</LinearLayout>