实际问题......也许

Question

我已经实现了ViewPager，RecyclerView和ContentProvider的基本设置。我似乎能够毫无问题地查询数据，但我无法在ViewPager选项卡中使用RecyclerView显示内容。

此处提供完整代码 - https://github.com/sudhirkhanger/PopularMovies

public class FavoriteFragment extends Fragment {

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

        // Set column size to 2 for default and portrait
        // and 3 for landscape orientations
        int column = Integer.parseInt(getString(R.string.grid_portrait));
        if (getResources().getConfiguration().orientation == 1) {
            column = Integer.parseInt(getString(R.string.grid_portrait));
        } else if (getResources().getConfiguration().orientation == 2) {
            column = Integer.parseInt(getString(R.string.grid_landscape));
        }

        mRecyclerView = (RecyclerView) rootView.findViewById(R.id.recyclerview);
        mRecyclerView.setHasFixedSize(true);
        mRecyclerView.setLayoutManager(new GridLayoutManager(getActivity(), column));

        ArrayList<Movie> mMovieArrayList = new ArrayList<Movie>();

        ContentResolver resolver = getActivity().getContentResolver();

        Cursor cursor =
                resolver.query(MovieContract.MovieEntry.CONTENT_URI,
                        null,
                        null,
                        null,
                        null);

        if (cursor != null) {
            if (cursor.moveToFirst()) {
                do {
                    String title = cursor.getString(cursor.getColumnIndex(MovieContract.MovieEntry.TITLE));
                    String movie_id = cursor.getString(cursor.getColumnIndex(MovieContract.MovieEntry.MOVIE_ID));
                    String poster = cursor.getString(cursor.getColumnIndex(MovieContract.MovieEntry.POSTER));
                    String backdrop = cursor.getString(cursor.getColumnIndex(MovieContract.MovieEntry.BACKDROP));
                    String overview = cursor.getString(cursor.getColumnIndex(MovieContract.MovieEntry.OVERVIEW));
                    String vote_average = cursor.getString(cursor.getColumnIndex(MovieContract.MovieEntry.VOTE_AVERAGE));
                    String release_date = cursor.getString(cursor.getColumnIndex(MovieContract.MovieEntry.DATE));

                    Movie movie = new Movie(title, release_date, poster,
                            vote_average, overview, backdrop, movie_id);
                    mMovieArrayList.add(movie);
                } while (cursor.moveToNext());
            }
        }

        if (cursor != null)
            cursor.close();

        for (Movie movie : mMovieArrayList) {
            Log.d("FavoriteFragment List", movie.getTitle());
        }

        mMovieAdapter = new MovieAdapter(getActivity(), mMovieArrayList);
        mMovieAdapter.notifyDataSetChanged();
        mRecyclerView.setAdapter(mMovieAdapter);
        return rootView;
    }

    public static FavoriteFragment newInstance() {
        Bundle args = new Bundle();
        FavoriteFragment fragment = new FavoriteFragment();
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onResume() {
        super.onResume();
        mRecyclerView.setAdapter(mMovieAdapter);
        mMovieAdapter.notifyDataSetChanged();
    }

    RecyclerView mRecyclerView;
    MovieAdapter mMovieAdapter;
}

如下所示，ArrayList包含数据。

04-25 22:02:36.216 4718-4718/com.sudhirkhanger.app.popularmoviesstageone W/FragmentManager: moveToState: Fragment state for PopularFragment{d7cf0b6 #1 id=0x7f0c006b} not updated inline; expected state 3 found 2
04-25 22:02:37.757 4718-4718/com.sudhirkhanger.app.popularmoviesstageone D/FavoriteFragment List: Whiplash
04-25 22:02:37.757 4718-4718/com.sudhirkhanger.app.popularmoviesstageone D/FavoriteFragment List: Batman v Superman: Dawn of Justice
04-25 22:02:37.757 4718-4718/com.sudhirkhanger.app.popularmoviesstageone D/FavoriteFragment List: Star Wars: The Force Awakens
04-25 22:02:37.757 4718-4718/com.sudhirkhanger.app.popularmoviesstageone D/FavoriteFragment List: The Shawshank Redemption
04-25 22:02:37.757 4718-4718/com.sudhirkhanger.app.popularmoviesstageone D/FavoriteFragment List: The Godfather
04-25 22:02:37.757 4718-4718/com.sudhirkhanger.app.popularmoviesstageone D/FavoriteFragment List: Interstellar
04-25 22:02:37.757 4718-4718/com.sudhirkhanger.app.popularmoviesstageone D/FavoriteFragment List: Captain America: Civil War
04-25 22:02:37.757 4718-4718/com.sudhirkhanger.app.popularmoviesstageone D/FavoriteFragment List: The Jungle Book
04-25 22:02:37.757 4718-4718/com.sudhirkhanger.app.popularmoviesstageone D/FavoriteFragment List: The Revenant
04-25 22:02:37.757 4718-4718/com.sudhirkhanger.app.popularmoviesstageone D/FavoriteFragment List: Jurassic World
04-25 22:02:37.757 4718-4718/com.sudhirkhanger.app.popularmoviesstageone D/FavoriteFragment List: Mad Max: Fury Road

Answer 1

我可能错了，但我认为您需要在onViewCreated中设置适配器。

Answer 2

首先，将onCreateView内的所有内容移至onViewCreated。只需返回rootView。它不是必需的，但它是良好的编码实践，并且在您尝试修复生命周期错误时将会有所帮助。另外，删除onResume方法。你没有做任何有帮助的事情。

其次，移动这些行：

mMovieAdapter = new MovieAdapter(getActivity(), mMovieArrayList);
mRecyclerView.setAdapter(mMovieAdapter);

在这一行的正下方：

ArrayList<Movie> mMovieArrayList = new ArrayList<Movie>();

然后，在使用所有数据填充列表后，请调用此行以告知回收站视图列表已更改：

mMovieAdapter.notifyDataSetChanged();

所以说完了，你就会有这个：

public class FavoriteFragment extends Fragment {

    RecyclerView mRecyclerView;
    MovieAdapter mMovieAdapter;

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

    @Override
    public void onViewCreated(View v, Bundle b) {
        // Set column size to 2 for default and portrait
        // and 3 for landscape orientations
        int column = Integer.parseInt(getString(R.string.grid_portrait));
        if (getResources().getConfiguration().orientation == 1) {
            column = Integer.parseInt(getString(R.string.grid_portrait));
        } else if (getResources().getConfiguration().orientation == 2) {
            column = Integer.parseInt(getString(R.string.grid_landscape));
        }

        mRecyclerView = (RecyclerView) rootView.findViewById(R.id.recyclerview);
        mRecyclerView.setHasFixedSize(true);
        mRecyclerView.setLayoutManager(new GridLayoutManager(getActivity(), column));

        ArrayList<Movie> mMovieArrayList = new ArrayList<Movie>();
        mMovieAdapter = new MovieAdapter(getActivity(), mMovieArrayList);
        mRecyclerView.setAdapter(mMovieAdapter);

        /* do all of your cursor stuff to populate the mMovieArrayList */
        ......

        // notify adapter to recycle 
        mMovieAdapter.notifyDataSetChanged();
    }

    public static FavoriteFragment newInstance() {
        Bundle args = new Bundle();
        FavoriteFragment fragment = new FavoriteFragment();
        fragment.setArguments(args);
        return fragment;
    }
}

Answer 3

我正在看项目并且：

MovieAdapter没问题，因为我在onCreateViewHolder和onBindViewHolder中设置了断点并且它们被击中了。
我无法验证查询是否正常，但通过查看您发布的日志记录可能无法正常查看。

实际问题......也许

似乎问题在于list_item.xml布局！我将其更改为LinearLayout而不是RelativeLayout，现在可以使用了。

list_item.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="vertical"
                android:padding="1dp">

    <ImageView
        android:id="@+id/imageview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:adjustViewBounds="true"
        android:scaleType="centerCrop"/>

    <TextView
        android:id="@+id/list_title"
        android:layout_width="match_parent"
        android:layout_height="@dimen/list_title_size"
        android:layout_alignBottom="@id/imageview"
        android:background="@color/black"
        android:ellipsize="end"
        android:gravity="center"
        android:maxLines="1"
        android:textColor="@color/white"
        android:textSize="@dimen/list_title_text_size"/>
</LinearLayout>

证据：

Answer 4

<ImageView
        android:id="@+id/imageview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:adjustViewBounds="true"
        android:scaleType="centerCrop"/>

ImageView高度设置为wrap_content。如果没有图像，则视图将不可见，尤其是在RelativeLayout中。当您拥有LinearLayout时，您就不会遇到此问题。

由于DetailsFragment.java中的输入错误，我将图像路径设置为final String poster = parcelableExtra.getReleaseDate();这是错误的。

有多种修复方法。

切换到LinearLayout
为ImageView设置修复高度。
确保图像没有损坏。

RecyclerView不会在ViewPager选项卡中填充数据

4 个答案:

实际问题......也许