相册艺术不使用适配器在列表视图中显示

我想在Custom ArrayAdapter的帮助下在列表视图中显示带有歌曲名称的专辑封面 .

我已经尝试了下面的代码，歌曲名称和艺术家名称显示完美但不是albumArt.I尝试使用Bitmap解码图像，但没有运气 .

这是我的ListSong类，用于使用MediaStore获取歌曲 .

package com.example.adityaverma.practicemusic;

import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.Context;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ListView;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.logging.Logger;

/**
 * Created by Aditya Verma on 17-10-2017.
 */

public class ListSong extends Fragment {

    private ArrayList<Song> songList;
    private ListView songView;
    private Context context;

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

        songView = (ListView) rootView.findViewById(R.id.songsList);
        songList = new ArrayList<Song>();

        getSongList();

        SongAdapter songAdt = new SongAdapter(getActivity(), songList);
        songView.setAdapter(songAdt);

        return rootView;

    }

    //This method is used to retrieve the songs from external storage of the device and adding them into our listview.

    public void getSongList() {
        ContentResolver musicResolver = getActivity().getContentResolver();
        Uri musicUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
        Cursor musicCursor = musicResolver.query(musicUri, null, null, null, null);
        if (musicCursor != null && musicCursor.moveToFirst()) {
            //get columns
            int titleColumn = musicCursor.getColumnIndex
                    (MediaStore.Audio.Media.TITLE);
            int idColumn = musicCursor.getColumnIndex
                    (MediaStore.Audio.Media._ID);
            int artistColumn = musicCursor.getColumnIndex
                    (MediaStore.Audio.Media.ARTIST);
            int albumid = musicCursor.getInt
                    (musicCursor.getColumnIndexOrThrow(MediaStore.Audio.Media.ALBUM_ID));

            Uri sArtworkUri = Uri.parse("content://media/external/audio/albumart");
            Uri albumArtUri = ContentUris.withAppendedId(sArtworkUri, albumid);

            Bitmap bitmap = null;
            try {
                bitmap = MediaStore.Images.Media.getBitmap(
                        context.getContentResolver(), albumArtUri);
                bitmap = Bitmap.createScaledBitmap(bitmap, 30, 30, true);

            } catch (FileNotFoundException exception) {
                exception.printStackTrace();
                bitmap = BitmapFactory.decodeResource(context.getResources(),
                        R.drawable.);
            } catch (IOException e) {

                e.printStackTrace();
            }


            //add songs to list
            do {
                long thisId = musicCursor.getLong(idColumn);
                String thisTitle = musicCursor.getString(titleColumn);
                String thisArtist = musicCursor.getString(artistColumn);
                long thisalbumid = musicCursor.getLong(albumid);

                songList.add(new Song(thisId, thisTitle, thisArtist , thisalbumid));
            }
            while (musicCursor.moveToNext());
            musicCursor.close();
        }

    }

}

这是我的bean类，用于存储SongInfo .

package com.example.adityaverma.practicemusic;

public class Song {

    private long id;
    private String title;
    private String artist;
    private long albumId;

    public Song(long songID, String songTitle, String songArtist , long songalbumId) {
        this.id = songID;
        this.title = songTitle;
        this.artist = songArtist;
        this.albumId = songalbumId;
    }

    public long getID(){return id;}
    public String getTitle(){return title;}
    public String getArtist(){return artist;}
    public long getAlbumId(){return albumId;}

}

最后这里是我的SongAdapter，它用于将ListView与ListSong类绑定 . 这就是我认为的问题所在 .

package com.example.adityaverma.practicemusic;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

import java.util.ArrayList;

public class SongAdapter extends BaseAdapter {

    private ArrayList<Song> songs;
    private LayoutInflater songInf;

    public SongAdapter(Context c, ArrayList<Song> theSongs) {
        songs = theSongs;
        songInf = LayoutInflater.from(c);
    }

    @Override
    public int getCount() {
        return songs.size();
    }

    @Override
    public Object getItem(int i) {
        return null;
    }

    @Override
    public long getItemId(int i) {
        return 0;
    }


    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        //map to song layout
        LinearLayout songLay = (LinearLayout) songInf.inflate
                (R.layout.songviewer, parent, false);
        //get title and artist views
        TextView songView = (TextView) songLay.findViewById(R.id.song_title);
        TextView artistView = (TextView) songLay.findViewById(R.id.song_artist);
        ImageView albumArtView = (ImageView) songLay.findViewById(R.id.albumArtSongs);
        //get song using position
        Song currSong = songs.get(position);
        //get title and artist strings
        songView.setText(currSong.getTitle());
        artistView.setText(currSong.getArtist());
        //set position as tag
        songLay.setTag(position);
        return songLay;
    }

}

我只想用正确的songName和艺术家名称显示我的albumArt .

注意：我只是这方面的初学者，所以请详细说明你的答案，并指出我错在哪里 . 并且可能会给出解释 .