Question

我正在开发一个Android媒体播放器。我是ANDROID的新手。我使用以下代码显示查询结果中的所有音乐。我想要每首歌一次，但如果我在适配器视图中设置文本大小，它会不止一次地显示一首歌而忽略许多其他歌曲，如下面的代码所示。如何在适配器视图中设置文本大小并避免此问题？

谢谢你

public class MusicAdapter extends BaseAdapter {
        private Context mContext;

        public MusicAdapter(Context c) {
              mContext = c;
        }

        public int getCount() {
              return count;
        }

        public Object getItem(int position) {
              return position;
        }

        public long getItemId(int position) {
              return position;
        }

        public View getView(int position, View convertView, ViewGroup parent) {
              System.gc();
              TextView tv = new TextView(mContext.getApplicationContext());
              tv.setTextSize(25);                     //THE PROBLEM IS HERE
              String id = null;
              if (convertView == null) {
                    music_column_index = musicCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DISPLAY_NAME);
                    musicCursor.moveToPosition(position);
                    id = musicCursor.getString(music_column_index);
                    music_column_index = musicCursor.getColumnIndexOrThrow(MediaStore.Audio.Media._ID);
                    musicCursor.moveToPosition(position);
                    String artist = musicCursor.getString(music_column_index);
                    id += "Artist:" + artist;
                    tv.setText(id);
              } else
                    tv = (TextView) convertView;
              return tv;
        }
  }

Answer 1

可能是因为你在try {}语句中写了相同的代码并且在while内？））

我的意思是这些界限：

path.add(musicCursor.getString(musicCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DATA)));
            title.add(musicCursor.getString(musicCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.TITLE)));
            artist.add(musicCursor.getString(musicCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.ARTIST)));
            album.add(musicCursor.getString(musicCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.ALBUM)));
            year.add(musicCursor.getString(musicCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.YEAR)));

Answer 2

我已经使用如下的SimpleCursorAdapter解决了这个问题。它是一个内置的适配器，非常聪明。 This link helped me a lot

你永远不应该设置listview的android：layout_height =“wrap_content”。它会导致重复出现列表项。

ListAdapter adapter = new SimpleCursorAdapter(this,
            // Use a template that displays a text view
            R.layout.list_item,
            // Give the cursor to the list adatper
            musicCursor,
            // Map the NAME column in the people database to...
            new String[] { MediaStore.Audio.Media.TITLE,
            MediaStore.Audio.Media.ARTIST },
            // The "text1" view defined in the XML template
            new int[] { R.id.music_title, R.id.music_artist });
    setListAdapter(adapter);

适配器视图上需要Android帮助来设置文本大小

2 个答案: