java - 滚动时 ListView 项目未锁定

标签 java android

我面临着巨大的挑战。我发现在对 CustomMusicAdapter 进行编码后，当我向上或向下滚动时，music_row 中的 ListView 项目不会保持其顺序。如果我向上滚动，第 5 行中的项目将被替换并移动到顶部。它是按升序排列的，当我尝试滚动时，项目分散了。因此，由于 ListView 项目的困惑，使得行项目变得杂乱无章，并且让读者感到无聊。 请我需要你的帮助。谢谢

这是主要 Activity 

public class MainActivity extends AppCompatActivity {
    private ArrayList<Music> arrayList;
    private CustomMusicAdapter adapter;
    private ListView songList;

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

        songList = (ListView) findViewById(R.id.songList);
        arrayList = new ArrayList<>();
        arrayList.add(new Music("001 Music", "Salutatio Actus paenitentialis", R.raw.adoremus_snctus));
        arrayList.add(new Music("002 Music", "Collecta, Liturgia Verbi (Prima & Secunda)", R.raw.adoremusl_collecta_liturgia_verbi));
        arrayList.add(new Music("003 Music", "Evangelium (Alleluia)", R.raw.evangelium_alleluia));
        arrayList.add(new Music("004 Music", "Evangelium (Responses)", R.raw.evangelium_responses));
        arrayList.add(new Music("005 Music", "Oratio universalis, Oratio super oblata", R.raw.oratio_universalis));
        arrayList.add(new Music("006 Music", "Prex Eucharistica (two versions)", R.raw.prex_eucharistica));
        arrayList.add(new Music("007 Music", "Praefatio (Sanctus)", R.raw.praefatio_sanctus));
        arrayList.add(new Music("008 Music", "Acclamans (Mortem tuam)", R.raw.acclamans_mortem_tuam));
        arrayList.add(new Music("009 Music", "Elevans, Ritus Communionis (Pater Noster)", R.raw.pater_noster));
        arrayList.add(new Music("010 Music", "Ritus Pacis", R.raw.ritus_pacis));
        arrayList.add(new Music("011 Music", "Oratio post communionem, Benedicto, Dimissio", R.raw.dimissio));
        arrayList.add(new Music("012 Music", "Penitential Act, Kyrie-Christe-Kyrie", R.raw.aud_3));
        arrayList.add(new Music("013 Music", "", R.raw.aud_3));
        arrayList.add(new Music("014 Music", "", R.raw.aud_3));
        arrayList.add(new Music("015 Music", "", R.raw.aud_3));
        arrayList.add(new Music("016 Music", "", R.raw.aud_3));


        adapter = new CustomMusicAdapter(this, R.layout.custom_music_row, arrayList);
        songList.setAdapter(adapter);

    }
}

这是CustomMusicAdapter

public class CustomMusicAdapter extends BaseAdapter {
    private Context context;
    private int layout;
    private ArrayList<Music> myArraylist;
    private MediaPlayer mediaPlayer;
    private boolean flag=true;

    public CustomMusicAdapter(Context context, int layout, ArrayList<Music> myArraylist) {
        this.context = context;
        this.layout = layout;
        this.myArraylist = myArraylist;
    }


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

    @Override
    public Object getItem(int i) {
        return myArraylist.get(i);
    }

    @Override
    public long getItemId(int i) {
        return 0;
    }
    public class ViewHolder{
        TextView textView_SongName, textView_artist;
        ImageView imageView_play, imageView_stop;
        private View convertview;
        LayoutInflater layoutInflater=(LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
        public ViewHolder(){
            convertview=layoutInflater.inflate(layout, null);
            textView_SongName = convertview.findViewById(R.id.textName);
            textView_artist = convertview.findViewById(R.id.txtSinger);
            imageView_play = convertview.findViewById(R.id.ivPlay);
            imageView_stop = convertview.findViewById(R.id.ivStop);

        }
    }

    @Override
    public View getView(int i, View convertView, ViewGroup parent) {
        final ViewHolder viewHolder = new ViewHolder();
        if (convertView==null){
            convertView = viewHolder.convertview;
        }else {

        }
        final Music music = myArraylist.get(i);
        viewHolder.textView_SongName.setText(music.getName());
        viewHolder.textView_artist.setText(music.getSinger());

        //Play Music Setup
        viewHolder.imageView_play.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                if (flag){
                    mediaPlayer=MediaPlayer.create(context,music.getSong());
                    flag=false;
                }
                if (mediaPlayer.isPlaying()){
                    mediaPlayer.pause();
                    mediaPlayer.start();
                    viewHolder.imageView_play.setImageResource(R.drawable.ic_play);
                }else {
                    mediaPlayer.start();
                    viewHolder. imageView_play.setImageResource(R.drawable.ic_pause);
                }
                mediaPlayer.start();

            }
        });

        // stop player
        viewHolder.imageView_stop.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (!flag){
                    mediaPlayer.stop();
                    mediaPlayer.release();
                    flag=true;
                }
                viewHolder.imageView_play.setImageResource(R.drawable.ic_play);
            }
        });
        return convertView;
    }
}

这是我到目前为止一直在做的事情，将我的代码转换为 ListView 的新方向

这是 custom_music_row

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    app:cardCornerRadius="7dp"
    app:cardElevation="4dp"
    app:cardUseCompatPadding="true">

    <RelativeLayout
        android:padding="16dp"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <ImageView
            android:id="@+id/ivMusic"
            android:layout_width="30dp"
            android:layout_height="40dp"
            android:layout_alignParentTop="true"
            android:src="@drawable/ic_lmusic" />

        <TextView
            android:id="@+id/textName"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentTop="true"
            android:layout_marginStart="48dp"
            android:text="Song List"
            android:textColor="#16c15b"
            android:textSize="22sp"
            android:layout_marginLeft="30dp" />

        <TextView
            android:id="@+id/txtSinger"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignStart="@+id/textName"
            android:layout_below="@+id/textName"
            android:text="Singer"
            android:textColor="#645506"
            android:textSize="18sp"
            android:layout_alignLeft="@+id/textName" />

        <ImageView
            android:id="@+id/ivPlay"
            android:layout_width="30dp"
            android:layout_height="30dp"
            android:layout_toLeftOf="@id/ivStop"
            android:layout_marginRight="20dp"
            android:src="@drawable/ic_play"/>

        <ImageView
            android:id="@+id/ivStop"
            android:layout_width="30dp"
            android:layout_height="30dp"
            android:src="@drawable/stop_outline"
            android:layout_alignParentRight="true"/>


    </RelativeLayout>

</android.support.v7.widget.CardView>

MyViewHolder 类

import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;

class MyViewHolder extends RecyclerView.ViewHolder {
    ImageView mImageaplay, mImageStop;
    TextView mTitle, mDes;

    public MyViewHolder(@NonNull View itemView) {
        super(itemView);

        this.mImageaplay = itemView.findViewById(R.id.ivPlay);
        this.mImageStop = itemView.findViewById(R.id.ivStop);
        this.mTitle = itemView.findViewById(R.id.textName);
        this.mDes = itemView.findViewById(R.id.txtSinger);
    }
}

我尝试对 CustomMusicAdapter 进行更改，但失败了!

public class CustomMusicAdapter extends RecyclerView.Adapter<MyViewHolder>{

    private Context context;
    private int layout;
    private ArrayList<Music> myArraylist;
    private MediaPlayer mediaPlayer;
    private boolean flag=true;

    public CustomMusicAdapter(Context context, int layout, ArrayList<Music> myArraylist, MediaPlayer mediaPlayer, boolean flag) {
        this.context = context;
        this.layout = layout;
        this.myArraylist = myArraylist;
        this.mediaPlayer = mediaPlayer;
        this.flag = flag;
    }

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        final View itemView = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.custom_music_row, parent, false);
        return new MyViewHolder(itemView);
    }



    @SuppressLint("RecyclerView")
    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder, final int position) {
        holder.setIsRecyclable(false);

        final Music music = myArraylist.get(position);
        holder.mTitle.setText(music.getName());
        holder.mDes.setText(music.getSinger());
        holder.mImageaplay.setImageResource(music.getSong());
        holder.mImageStop.setImageResource(music.getSong());

    }

    @Override
    public int getItemCount() {
        return 0;
    }
}

enter image description here

最佳答案

尝试一下

  public class MainActivity extends AppCompatActivity {
    private ArrayList<Music> arrayList;
    private CustomMusicAdapter adapter;
    private RecyclerView recyclerView;

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

    recyclerView =  findViewById(R.id.recyclerView);
    arrayList = new ArrayList<>();
    arrayList.add(new Music("001 Music", "Salutatio Actus paenitentialis", R.raw.adoremus_snctus));
   ...



   adapter = new CustomMusicAdapter(YOUR_ACTIVITY.this, arrayList);
       recyclerView.setAdapter(adapter);
       recyclerView.setHasFixedSize(false);

}
}

适配器:

public class CustomMusicAdapter extends RecyclerView.Adapter<CustomMusicAdapter.MyViewHolder> {
private Context context;
private int layout;
private ArrayList<Music> myArraylist;
private MediaPlayer mediaPlayer;
private boolean flag=true;

public CustomMusicAdapter(Context context, ArrayList<Music> myArraylist) {
    this.context = context;
    this.myArraylist = myArraylist;
}

 @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        final View itemView = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.custom_music_row, parent, false);
        return new MyViewHolder(itemView);
    }



@SuppressLint("RecyclerView")
    @Override
    public void onBindViewHolder(@NonNull final MyViewHolder holder, final int position) {
final ViewHolder viewHolder = new ViewHolder();
            holder.setIsRecyclable(false);

        final Music music = myArraylist.get(i);
        viewHolder.textView_SongName.setText(music.getName());
        viewHolder.textView_artist.setText(music.getSinger());



      //Play Music Setup
        viewHolder.imageView_play.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                if (flag){
                    mediaPlayer=MediaPlayer.create(context,music.getSong());
                    flag=false;
                }
                if (mediaPlayer.isPlaying()){
                    mediaPlayer.pause();
                    mediaPlayer.start();
                    viewHolder.imageView_play.setImageResource(R.drawable.ic_play);
                }else {
                    mediaPlayer.start();
                    viewHolder. imageView_play.setImageResource(R.drawable.ic_pause);
                }
                mediaPlayer.start();

            }
        });

        // stop player
        viewHolder.imageView_stop.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (!flag){
                    mediaPlayer.stop();
                    mediaPlayer.release();
                    flag=true;
                }
                viewHolder.imageView_play.setImageResource(R.drawable.ic_play);
            }
        });
}
   @Override
    public int getCount() {
        return myArraylist.size();
    }


    public class ViewHolder{
        TextView textView_SongName, textView_artist;
        ImageView imageView_play, imageView_stop;
        private View convertview;
        LayoutInflater layoutInflater=(LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
        public ViewHolder(){
            convertview=layoutInflater.inflate(layout, null);
            textView_SongName = convertview.findViewById(R.id.textName);
            textView_artist = convertview.findViewById(R.id.txtSinger);
            imageView_play = convertview.findViewById(R.id.ivPlay);
            imageView_stop = convertview.findViewById(R.id.ivStop);

        }
    }
    }

关于java - 滚动时 ListView 项目未锁定，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/60862868/

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