如何传递整个数组列表到另一个活动

Question

我正在制作一个mp3播放器应用程序，在我的主要活动中，我显示了回收器视图中所有歌曲的列表，当用户点击歌曲时，我试图将歌曲的整个数组列表发送到我的播放器活动，在那里我可以为下一个和以前的歌曲播放工作，但我的应用程序崩溃时点击歌曲

Process: com.choudhary.musicplayer, PID: 8686
java.lang.RuntimeException: Parcel: unable to marshal value com.choudhary.musicplayer.AudioModel@a0de380
at android.os.Parcel.writeValue(Parcel.java:1667)
at android.os.Parcel.writeList(Parcel.java:966)
at android.os.Parcel.writeValue(Parcel.java:1614)
at android.os.Parcel.writeArrayMapInternal(Parcel.java:878)
at android.os.BaseBundle.writeToParcelInner(BaseBundle.java:1588)
at android.os.Bundle.writeToParcel(Bundle.java:1233)
at android.os.Parcel.writeBundle(Parcel.java:918)
at android.content.Intent.writeToParcel(Intent.java:9987)
at android.app.IActivityManager$Stub$Proxy.startActivity(IActivityManager.java:3636)
at android.app.Instrumentation.execStartActivity(Instrumentation.java:1675)
at android.app.Activity.startActivityForResult(Activity.java:4651)
at androidx.activity.ComponentActivity.startActivityForResult(ComponentActivity.java:597)
at android.app.Activity.startActivityForResult(Activity.java:4609)
at androidx.activity.ComponentActivity.startActivityForResult(ComponentActivity.java:583)
at android.app.Activity.startActivity(Activity.java:4970)
at android.app.Activity.startActivity(Activity.java:4938)
at com.choudhary.musicplayer.MusicAdapter$1.onClick(MusicAdapter.java:54)
at android.view.View.performClick(View.java:6608)
at android.view.View.performClickInternal(View.java:6585)
at android.view.View.access$3100(View.java:785)
at android.view.View$PerformClick.run(View.java:25921)

适配器的OnBind方法:——

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

holder.name.setText(arrayList.get(position).getaName());
holder.album.setText(arrayList.get(position).getaAlbum());
holder.imageView.setImageBitmap(BitmapFactory.decodeFile(arrayList.get(position).getAlbumart()));
holder.imageView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent in = new Intent(context,PlayerActivity.class);
in.putExtra("SONG",arrayList.get(position).getaName());
in.putExtra("PATH",arrayList.get(position).getaPath());
in.putExtra("ALBUM",arrayList.get(position).getaAlbum());
in.putExtra("LIST",arrayList);
in.putExtra("POSITION",  arrayList.get(position).toString());
context.startActivity(in);
}
});

}

my Player Activity:——

public class PlayerActivity extends AppCompatActivity {
TextView songanme, songAlbum,duration,movetime;
ImageView playbutton,nextbtn,previousbtn;
SeekBar seekBar;
MediaPlayer mediaPlayer ;
ArrayList<AudioModel>  list;
int CURRENT_POSITION ;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_player);
songanme = findViewById(R.id.music_name_pl);
movetime = findViewById(R.id.move_time);
seekBar = findViewById(R.id.seekBar);
songAlbum = findViewById(R.id.music_album_pl);
duration = findViewById(R.id.duration);
playbutton = findViewById(R.id.play_btn_pl);
nextbtn = findViewById(R.id.next_btn_pl);
previousbtn = findViewById(R.id.previous_pl);
list = new ArrayList<>();
songanme.setSelected(true);

Intent intent = getIntent();
Bundle bundle = intent.getExtras();
list =    (ArrayList) bundle.getParcelableArrayList("LIST");

}

Answer 1

假设您想将Song类的ArrayList从Activity1传递给Activity2。

1—Song类应实现Serializable类。

应该是这样的…

import java.io.Serializable;
public class Song implements Serializable {
String name;
String album;
public Song(String name, String album) {
this.name = name;
this.album = album;
}
}

2-在Activity1传递你的数组列表对象作为一个额外的Ativity2

ArrayList<Song> songs= new ArrayList();
songs.add(new Song("song1","album1"));
songs.add(new Song("song2","album2"));
songs.add(new Song("song3","album3"));
Intent intent=new Intent(this,Activity2.class);
intent.putExtra("songs",songs);
startActivity(intent);

3-最终接收Activity2

中getSerializableExtra的数组列表

ArrayList<Song> songs = (ArrayList<Song>) getIntent().getSerializableExtra("songs");
Log.i("HINT", "" + songs.size());

Answer 2

你可以创建一个单例类来在android的不同组件之间共享你的ArrayList。单例类的示例代码如下-

public class SongBank
{
private static SongBank instance;
private ArrayList<Song> songsArrayList;
private SongBank(Context context)
{
// You can do any stuff if you want here      
}

// create getter and setter methods for your arrayList
public void setSongsList(ArrayList<Song> songs)
{
if(songs!=null)
{
this.songsArrayList=songs; 
}
}
public ArrayList<Song> getSongsList()
{
return this.songsArrayList;
}

public static SongBank getInstance(Context context)
{
if(instance==null)
{
instance=new SongBank(context);
}  
return instance;
}

}

这个单例类的实例可以在不同的活动或片段中调用，如果你想的话，你也可以在不同的活动中改变数组列表的值。你也可以调用这个类，在你的音乐服务中获取列表，而不用担心序列化问题。