如果我有一個類 PlayList 一個類歌曲和一個類廣告，并且我創(chuàng)建一個 Listplaylist（在另一個名為 Index 的類中）我如何將歌曲添加（或添加）到播放列表？它不允許我這樣做。我不允許在那里使用 .add（索引）public static void PrintPlayList() { int songsNumber = songs.size(); int addsNumber = adds.size(); for(int i=0; i<songsNumber;i++) { playlist.add(songs.get(i)); } 在那里聲明列表之后 public static List<PlayListStuff> playlist = new ArrayList<PlayListStuff>();并有字段歌曲并添加到類 PlayListStuffpublic class PlayListStuff { private Song song; private Add add;}public PlayListStuff(Song song) { super(); this.song = song; } public PlayListStuff( Add add) { super(); this.add = add; }
2 回答
慕標5832272
TA貢獻1966條經驗 獲得超4個贊
您只能將PlayListStuff對象添加到播放列表中。
Song并且Add應該擴展PlayListStuff.
喜歡
public class PlayListStuff {}
public class Song extends PlayListStuff {}
public class Add extends PlayListStuff {}
慕婉清6462132
TA貢獻1804條經驗 獲得超2個贊
public final class PlayList {
private final List<Stuff> stuffs = new ArrayList<>();
public void addStuff(Stuff stuff) {
stuffs.add(stuff);
}
public interface Stuff {}
}
public class Song implements PlayList.Stuff {}
public class Add implements PlayList.Stuff {}
您的客戶端代碼可能如下所示：
PlayList playList = new PlayList();
playList.addStuff(new Song());
playList.addStuff(new Add());
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