Question

我正在构建一个音乐播放器，即使我的应用程序关闭后我想要存储我的播放列表，并在应用程序启动时检索回来。我现在能够在Array List中获得播放列表。请帮忙..

Answer 1

要在应用程序关闭时保存某些内容，请覆盖活动或片段中的onPause方法，然后从ArrayList中保存播放列表，可能是在sqlite数据库，文件或共享首选项中。要检索它，请在onCreate方法中编写代码，然后就可以检索保存的数据。

我没有处理sqlite，但如果你想

，那么你就是一个共享偏好代码

class Playlist {
    private final String fileName = "myPlaylist";
    private SharedPreferences myPlaylist;
    private SharedPreferences.Editor myEditor;

    Playlist() {
        myPlaylist = getSharedPreferences(fileName, 0);
        myEditor = myPlaylist.edit();
    }

    public void save(ArrayList<String> mySongs){
        // Save the size so that you can retrieve the whole list later
        myEditor.putInt("listSize", mySongs.size());

        for(int i = 0; i < mySongs.size(); i++){
            // Save each song with its index in the list as a key
            myEditor.putString(String.valueOf(i), mySongs.get(i));
        }

        myEditor.commit();
    }

   public ArrayList<String> load() {
        // Create new array to be returned
        ArrayList<String> savedSongs = new ArrayList<String>();

        // Get the number of saved songs
        int numOfSavedSongs = myPlaylist.getInt("listSize", 0);

        // Get saved songs by their index
        for (int i = 0; i < numOfSavedSongs; i++) {
            savedSongs.add(myPlaylist.getString(String.valueOf(i)));
        }

        return savedSongs;
    }
}

抱歉，如果代码包含错误，但我没有测试它。希望它有所帮助

如何以编程方式在Android中存储播放器的播放列表

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