单击时更新ListView的单行中的视图 [英] Updating views within a single row of a ListView when clicked

问题描述

我想知道如何在单击行时更新ListView的单行中的视图/UI(例如，使TextView不可见)，因为其他行的观点也会受到影响.一个很好的例子是在Google Play音乐中播放歌曲，并相应地显示均衡器动画.这是我的摘录:

I was wondering how to update views/UI (say, making a TextView invisible) within a single row of a ListView when clicking on the row because every other rows' views would be affected as well. A good example would be playing a song in Google Play Music, and the equalizer animation would be displayed accordingly. Here are my snippets:

MainActivity的onCreate():

MainActivity's onCreate():

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main); // Renders only a ListView

    ListView songListView = (ListView) findViewById(R.id.list);
    List<Song> songList = new ArrayList<>();
    for (int i = 1; i <= 200; i++) songList.add(new Song("Song" + i, "Artist" + i));
    SongAdapter songAdapter = new SongAdapter(this, songList);
    songListView.setAdapter(songAdapter);
    songListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long l) {
            if (position == view.getId()) {
                TextView titleText = (TextView) view.findViewById(R.id.song_title);
                titleText.setVisibility(View.INVISIBLE);
            }
        }
    });
}

...以及我的ArrayAdapter的getView方法和ViewHolder类:

... and my ArrayAdapter's getView method and ViewHolder class:

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder holder;

    if (convertView == null) {
        convertView = LayoutInflater.from(getContext()).inflate(R.layout.list_item, parent,
                false);

        holder = new ViewHolder();
        holder.song = (TextView) convertView.findViewById(R.id.song_title);
        holder.artist = (TextView) convertView.findViewById(R.id.song_artist);

        convertView.setTag(holder);
    } else {
        holder = (ViewHolder) convertView.getTag();
    }

    convertView.setId(position);

    Song currentSong = getItem(position);

    if (currentSong != null) {
        holder.song.setText(currentSong.getTitle());
        holder.artist.setText(currentSong.getArtist());
    }

    return convertView;
}

private static class ViewHolder {
    TextView song;
    TextView artist;
}

推荐答案

在得到导师的帮助后，我终于明白了这一点.初始化适配器中的int字段以保留列表中先前位置的记录可达到以下目的:

I finally figured this out after getting help from my mentor. Initializing an int field in the adapter to keep record of previous positions in the list did the trick as follows:

MainActivity:

MainActivity:

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ListView songListView = (ListView) findViewById(R.id.list);
        List<Song> songList = new ArrayList<>();
        for (int i = 1; i <= 200; i++) songList.add(new Song("Song" + i, "Artist" + i));
        final SongAdapter songAdapter = new SongAdapter(this, songList);
        songListView.setAdapter(songAdapter);
        songListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long l) {
                songAdapter.setSongPosition(position);
                songAdapter.notifyDataSetChanged();
            }
        });
    }
}

自定义歌曲课程:

public class Song {
    private String mSongTitle, mSongArtist;

    public Song(String songTitle, String songArtist) {
        mSongTitle = songTitle;
        mSongArtist = songArtist;
    }

    public String getSongTitle() {
        return mSongTitle;
    }

    public String getSongArtist() {
        return mSongArtist;
    }
}

自定义适配器:

public class SongAdapter extends ArrayAdapter<Song> {
    private int currentlyPlaying = -1;

    public SongAdapter(Context context, List<Song> songList) {
        super(context, 0, songList);
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;

        if (convertView == null) {
            convertView = LayoutInflater.from(getContext()).inflate(R.layout.list_item, parent,
                    false);

            holder = new ViewHolder(convertView);

            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }

        Song song = getItem(position);
        holder.song.setText(song.getSongTitle());
        holder.artist.setText(song.getSongArtist());

        // Hides the row, so both TextViews. Otherwise, sets each row visible.
        if (position == currentlyPlaying) convertView.setVisibility(View.INVISIBLE);
        else convertView.setVisibility(View.VISIBLE);

        return convertView;
    }

    private class ViewHolder {
        private TextView song;
        private TextView artist;

        private ViewHolder(View itemView) {
            song = (TextView) itemView.findViewById(R.id.song_title);
            artist = (TextView) itemView.findViewById(R.id.artist);
        }
    }

    public void setSongPosition(int position) {
        currentlyPlaying = position;
    }
}

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