Question

我有一个使用MediaPlayer类从互联网上播放音乐的应用程序。我使用了recyclerview，在每个项目上，它都有一个播放/按钮按钮来开始播放和暂停声音。当用户点击其他项目播放按钮时，如何更改播放按钮以暂停按钮？

public class Adapter extends RecyclerView.Adapter<Adapter.Viewholder> {

private List<Track> tracks;
private Context context;

public Adapter(List<Track> tracks, Context context) {
    this.tracks = tracks;
    this.context = context;
}

@NonNull
@Override
public Viewholder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.track_item, parent, false);
    return new Viewholder(view);
}

@Override
public void onBindViewHolder(@NonNull final Viewholder holder, final int position) {


    holder.title.setText(tracks.get(position).getTitle());
    holder.id.setText(tracks.get(position).getId());
    Glide.with(context).load(tracks.get(position).getImgurl()).into(holder.trackImage);
   holder.btnPlay.setOnClickListener(new View.OnClickListener() {
       @Override
       public void onClick(View v) {

           holder.btnPause.setVisibility(View.VISIBLE);
           Intent intent = new Intent(context, Player.class);
           intent.putExtra("URL", tracks.get(position).getMusicurl());
           context.startService(intent);

       }
   });

   holder.btnPause.setOnClickListener(new View.OnClickListener() {
       @Override
       public void onClick(View v) {
           Player.killMediaPlayer();
           holder.btnPause.setVisibility(View.INVISIBLE);
       }
   });

}

@Override
public int getItemCount() {
    return tracks.size();
}


public static class Viewholder extends RecyclerView.ViewHolder {

    TextView title, id;
    ImageView trackImage;
     ImageButton btnPlay;

    public Viewholder(View itemView) {
        super(itemView);
        title = itemView.findViewById(R.id.title);
        id = itemView.findViewById(R.id.id);
        trackImage = itemView.findViewById(R.id.trackImage);
        btnPlay = itemView.findViewById(R.id.play);
    }
}

}

Answer 1

非常简单，只需遍历整个数据集，并将所有数据集设置为暂停，但当前的数据集除外。然后调用notifyDatasetChanged();

Answer 2

你可以使用notifyDataSetChange（） - 它会更新所有的recyclerView项目
使用notifyItemChanged（poition） - 它会更新特定位置。

注意：假设您的手机屏幕上有8个项目，并且您将暂停作为第1个位置，第9个位置将显示为暂停。要解决此问题，请尝试比较之前的song_title / artist名称通知

Answer 3

你必须使用 notifyDataSetChanged（） - 它会重置所有的recyclerView项目 ，然后使用 notifyItemChanged（poition）或 mList.get（getAdapterPosition（）） - 它会更新具体位置。

Answer 4

以下是示例代码：

public class MainActivity extends AppCompatActivity {
private TrackAdapter trackAdapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    RecyclerView recyclerView = findViewById(R.id.reycleView);
    ((SimpleItemAnimator) recyclerView.getItemAnimator()).setSupportsChangeAnimations(false);

    trackAdapter = new TrackAdapter();
    trackAdapter.setCallBack(new CallBackImpl());
    trackAdapter.setTracks(getTracks());
    RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(this);
    recyclerView.setLayoutManager(mLayoutManager);
    recyclerView.setHasFixedSize(true);
    recyclerView.setAdapter(trackAdapter);


}

private List<Track> tracks;

private List<Track> getTracks() {
    tracks = new ArrayList<>();
    for (int i = 0; i < 50; i++) {
        Track track = new Track();
        track.setTrackName(" Track " + i);
        track.setPlaying(false);
        tracks.add(track);
    }
    return tracks;

}

int currentPosition = -1;

private class CallBackImpl implements TrackAdapter.CallBack {
    @Override
    public void clicked(int position) {
        Track track = tracks.get(position);
        tracks.get(position).setPlaying(!track.isPlaying());
        if (currentPosition >-1) {
            track = tracks.get(currentPosition);
            tracks.get(currentPosition).setPlaying(!track.isPlaying());
        }
        trackAdapter.setTracks(tracks);
        trackAdapter.notifyItemChanged(currentPosition);
        trackAdapter.notifyItemChanged(position);
        currentPosition = position;
    }
}
}

TrackAdapter.java

public class TrackAdapter extends RecyclerView.Adapter<TrackAdapter.VH> {
private int current;

public void setCallBack(CallBack callBack) {
    this.callBack = callBack;
}

private CallBack callBack;
interface  CallBack
{
    void clicked(int position);
}

public void setTracks(List<Track> tracks) {
    this.tracks = tracks;
}

private List<Track> tracks;

@Override
public VH onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.layout, parent, false);
    return new VH(view);
}

@Override
public void onBindViewHolder(VH holder, int position) {
    holder.setData(tracks.get(position));

}

@Override
public int getItemCount() {
    if (tracks == null) {
        return 0;
    } else {
        return tracks.size();
    }

}


class VH extends RecyclerView.ViewHolder {
    TextView textView;

    TextView playView;

    public VH(View itemView) {
        super(itemView);
        textView = itemView.findViewById(R.id.track);
        playView = itemView.findViewById(R.id.trackplay);
        playView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (callBack!=null)
                {
                    callBack.clicked(getAdapterPosition());
                }

            }
        });
    }

    void updateState(boolean isPlaying) {
        if (isPlaying) {
            current = getAdapterPosition();
            playView.setText("Playing");
        } else {
            playView.setText("Stopped");
        }

    }

    void setData(Track data) {
        textView.setText(data.getTrackName());
        updateState(data.isPlaying());
    }
}
  }

跟踪.java

 public class Track {
 private boolean isPlaying;

public String getTrackName() {
    return trackName;
}

public void setTrackName(String trackName) {
    this.trackName = trackName;
}

private String trackName;

public boolean isPlaying() {
    return isPlaying;
}

public void setPlaying(boolean playing) {
    isPlaying = playing;
}
 }

layout.xml

    <?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:orientation="vertical"
android:layout_height="wrap_content">
<TextView
android:id="@+id/track"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
    android:id="@+id/trackplay"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

   </LinearLayout>

点击已在停止文字上实施。

Answer 5

holder.btnPlay.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(Track.isPlaying()){
                    notifyItemChanged(currentItem, holder );
                }

                Track.setPlaying(true);
                currentItem = holder.getAdapterPosition();
                Log.i("TAG", "Position : " + currentItem);
                holder.equalizer.setVisibility(View.VISIBLE);
                holder.btnPause.setVisibility(View.VISIBLE);
                holder.btnPlay.setVisibility(View.INVISIBLE);
                Intent intent = new Intent(context, Player.class);
                intent.putExtra("URL", tracks.get(position).getMusicurl());
                intent.putExtra("ID", tracks.get(position).getId());
                context.startService(intent);

            }
        });

点击某个项目时如何更新recycleler查看其他项目？

5 个答案: