Question

经过多次尝试和尝试方法并观察了其他stackoverflow代码之后，我便能够将数据发送到下一个活动。我想知道：在onBindViewHolder方法中两次调用cursor.moveToPosition是否安全。

public class recyclerViewSongAdapter extends RecyclerView.Adapter<recyclerViewSongAdapter.MyViewHolder> {
        private final Activity callingActivity;
        private final Cursor songCursor;

        public recyclerViewSongAdapter(Activity activity, Cursor cursor) {
            callingActivity = activity;
            songCursor = cursor;
            if(songCursor != null) {
                songPathIndex = songCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DATA);
                songTitleIndex = songCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.TITLE);
                songAlbumIndex = songCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.ALBUM);
            }
        }

        public class MyViewHolder extends RecyclerView.ViewHolder { //implements View.OnClickListener{
            public TextView titleTextView, albumTextView;
            public View parentLayout;

            public MyViewHolder(View view) {
                super(view);
                titleTextView = view.findViewById(R.id.songTitleId);
                albumTextView = view.findViewById(R.id.songAlbumId);
                parentLayout = view.findViewById(R.id.parentLinearId);

            }
        }

        @NonNull
        @Override
        public MyViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
            View itemView = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.song_element, viewGroup, false);
            return new MyViewHolder(itemView);
        }

        public String songTitle, songAlbum;
        int songPathIndex, songTitleIndex, songAlbumIndex;

        @Override
        public void onBindViewHolder(@NonNull final MyViewHolder myViewHolder, final int position) {
            if(songCursor != null) {
                songCursor.moveToPosition(position);
                songTitle = songCursor.getString(songTitleIndex);
                songAlbum = songCursor.getString(songAlbumIndex);

                myViewHolder.titleTextView.setText("" + songTitle);
                myViewHolder.albumTextView.setText("" + songAlbum);

                myViewHolder.parentLayout.setOnClickListener(new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        songCursor.moveToPosition(position);
                        string title = songCursor.getString(songTitleIndex); 
                        Intent intent = new Intent(callingActivity.getApplicationContext(), SongPlaying.class);
                        intent.putExtra("mayank", "" + title);
                        callingActivity.startActivity(intent);
                    }
                });
            }
        }

        @Override
        public int getItemCount() {
            return (songCursor == null) ? 0 : songCursor.getCount();
        }
    }

编辑：之前，我的问题是如何将单击项的标题发送到下一个活动，现在我的问题是两次使用cursor.moveToPosition，一个好主意。

Answer 1

这不是在回收站适配器中使用游标的正确方法，但这是一种将当前标题发送到下一个活动的解决方案。

在您的onclick侦听器中编写以下代码

    songCursor.moveToPosition(position);
    String title= songCursor.getString(songTitleIndex);
    Intent intent = new Intent(callingActivity.this,SongPlaying.class);
    intent.putExtra("mayank", "" + title);
    callingActivity.startActivity(intent);

将数据从recyclerView适配器发送到新活动时出现问题

1 个答案: