Java 在片段方法内调用活动方法

我对这个有点陌生。也许我在做一些非常愚蠢的事情

我的问题是：有一种方法可以在片段方法内部获得活动方法？

public class MyMusic extends Fragment {

    private static  final int MY_PERMISSION_REQUEST = 1;
    SongScreen songScreen = new SongScreen();

   static ArrayList<Song> songList = new ArrayList<Song>();;
    ListView songView;
    String songTitle, songArtist, durationSong, songAlbum;
    Song currentSong;
    int position;

    public MyMusic()
    {}

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

        //List View
        songView = (ListView) view.findViewById(R.id.my_music);
        songList = new ArrayList<Song>();

        if (ActivityCompat.checkSelfPermission(getContext(),
                Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED){
            if(ActivityCompat.shouldShowRequestPermissionRationale(getActivity(),
                    android.Manifest.permission.READ_EXTERNAL_STORAGE)){
                ActivityCompat.requestPermissions(getActivity(),
                        new String[]{android.Manifest.permission.READ_EXTERNAL_STORAGE}, MY_PERMISSION_REQUEST);
            }else {
                ActivityCompat.requestPermissions(getActivity(),
                        new String[]{android.Manifest.permission.READ_EXTERNAL_STORAGE}, MY_PERMISSION_REQUEST);
            }
        } else {
            accessfiles();
        }
        return view;
    }

    public void accessfiles(){

      //  songList = new ArrayList<Song>();

        Cursor song = getMusic();
        SongAdapter songAdt = new SongAdapter(this.getContext(), songList);
        songView.setAdapter(songAdt);

        //When you click on the item pass to a new fragment with all the info
        songView.setOnItemClickListener(new AdapterView.OnItemClickListener(){
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {

                String songTitle = ((TextView) view.findViewById(R.id.titleSong)).getText().toString();
                String songArtist = ((TextView) view.findViewById(R.id.artistSong)).getText().toString();
                String durationSong = ((TextView) view.findViewById(R.id.songDuration)).getText().toString();
                 Song currentSong = songList.get(position);
                String songAlbum = currentSong.getAlbum();
                passingToScreen(songTitle,songArtist,durationSong,songAlbum);
                //Path have the path of the song
                String path = currentSong.getPathSong();
                ((MainActivity)getActivity()).playerStart(path ,currentSong);



    }});
    }
    private void passingToScreen(String songTitle, String songArtist, String durationSong, String songAlbum) {
        Bundle bundle = new Bundle();
        bundle.putString("songTitle", songTitle);
        bundle.putString("songArtist", songArtist);
        bundle.putString("durationSong", durationSong);
        bundle.putString("songAlbum", songAlbum);

        FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        songScreen.setArguments(bundle);
        fragmentTransaction.replace(R.id.layoutCM,
                songScreen,
                songScreen.getTag()).commit();

    }

    public Cursor getMusic(){
        Context context = getContextOfApplication();
        ContentResolver contentResolver = context.getContentResolver();
        Uri songUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
        Cursor songcursor = contentResolver.query(songUri, null, null, null, null);


        if (songcursor != null && songcursor.moveToFirst()){
            int songId = songcursor.getColumnIndex(MediaStore.Audio.Media._ID);
            int songTitle = songcursor.getColumnIndex(MediaStore.Audio.Media.TITLE);
            int songArtist = songcursor.getColumnIndex(MediaStore.Audio.Media.ARTIST);
            int songAlbum = songcursor.getColumnIndex(MediaStore.Audio.Media.ALBUM);
            int songDuration = songcursor.getColumnIndex(MediaStore.Audio.Media.DURATION);
            int pathSong = songcursor.getColumnIndex(MediaStore.Audio.Media.DATA);

            do{
                Long currentId = songcursor.getLong(songId);
                String currentTitle = songcursor.getString(songTitle);
                String currentArtist = songcursor.getString(songArtist);
                String currentAlbum = songcursor.getString(songAlbum);
                Long currentDuration = songcursor.getLong(songDuration);
                String currentPath = songcursor.getString(pathSong);

                songList.add(new Song(currentId, currentTitle, currentArtist, currentDuration, currentAlbum, currentPath ));
            }
            while (songcursor.moveToNext());
        }
        return songcursor;
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        switch (requestCode){
            case MY_PERMISSION_REQUEST: {
                if(grantResults.length>0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){
                   if(ContextCompat.checkSelfPermission(getContext(),
                           Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED){

                       accessfiles();
                   }
                }
            }
        }
    }


    public void getNext(Song currentSong) {

        if (songList.contains(currentSong))
        {
           int position1 = songList.indexOf(currentSong);
            if(position1 > songList.size())
            {
                String nextSong = songList.get(0).getPathSong();
                Song next = songList.get(0);
                ((MainActivity)getActivity()).playerStart(nextSong, next);


            }else{
                String nextSong = songList.get(position1+1).getPathSong();
                Song next = songList.get(position1 + 1);
                ((MainActivity)getActivity()).playerStart(nextSong, next);
                }
            }
        }



    public void getPrevious(Song currentSong) {
        int position = (int) (currentSong.getID() - 1);
        if(position < 0)
        {
            String previousSong = songList.get(songList.size()).getPathSong();
            Song previous = songList.get(songList.size());
            ((MainActivity)getActivity()).playerStart(previousSong, previous);

        }else{
            String previousSong = songList.get(position).getPathSong();
            Song previous = songList.get(songList.size());
            ((MainActivity)getActivity()).playerStart(previousSong, previous);
        }

    }
}

公共类MyMusic扩展片段{
私有静态final int MY_PERMISSION_REQUEST=1；
SongScreen SongScreen=新的SongScreen（）；
静态ArrayList歌曲列表=新ArrayList（）；；
列表视图；
弦乐歌曲名称，歌曲艺术家，durationSong，歌曲专辑；
歌曲；
内部位置；
公共音乐（）
{}
@凌驾
创建视图上的公共视图（布局、充气机、视图组容器、，
Bundle savedInstanceState）{
视图=充气机。充气（R.layout.my_music，container，false）；
//列表视图
songView=（ListView）view.findViewById（R.id.my_music）；
songList=newarraylist（）；
如果（ActivityCompat.checkSelfPermission）（getContext（），
Manifest.permission.READ（外部存储）！=PackageManager.permission（已授予）{
如果（ActivityCompat.shouldShowRequestPermissionRegulation）（getActivity（），
android.Manifest.permission.READ\u外部存储）{
ActivityCompat.requestPermissions（getActivity（），
新字符串[]{android.Manifest.permission.READ\u EXTERNAL\u STORAGE}，MY\u permission\u REQUEST）；
}否则{
ActivityCompat.requestPermissions（getActivity（），
新字符串[]{android.Manifest.permission.READ\u EXTERNAL\u STORAGE}，MY\u permission\u REQUEST）；
}
}否则{
accessfiles（）；
}
返回视图；
}
公共void accessfiles（）{
//songList=newarraylist（）；
光标歌曲=getMusic（）；
SongAdapter songAdt=新的SongAdapter（this.getContext（），songList）；
songView.setAdapter（songAdt）；
//当你点击项目时，传递给一个包含所有信息的新片段
songView.setOnItemClickListener（新的AdapterView.OnItemClickListener（）{
@凌驾
public void onItemClick（AdapterView父对象、视图、整型位置、长id）{
字符串songTitle=（（TextView）view.findViewById（R.id.titleSong））.getText（）.toString（）；
String songArtist=（（TextView）view.findViewById（R.id.artistSong））.getText（）.toString（）；
字符串durationSong=（（TextView）view.findViewById（R.id.songDuration））.getText（）.toString（）；
Song currentSong=songList.get（位置）；
String songAlbum=currentSong.getAlbum（）；
passingToScreen（歌曲标题、歌曲艺术家、durationSong、歌曲专辑）；
//路有歌的路
字符串路径=currentSong.getPathSong（）；
（（MainActivity）getActivity（））.playerStart（路径，currentSong）；
}});
}
private void passingToScreen（弦乐歌曲标题、弦乐歌曲艺术家、弦乐歌曲持续时间、弦乐歌曲专辑）{
Bundle=新Bundle（）；
bundle.putString（“songTitle”，songTitle）；
bundle.putString（“歌曲艺术家”，歌曲艺术家）；
bundle.putString（“durationSong”，durationSong）；
bundle.putString（“songAlbum”，songAlbum）；
FragmentManager FragmentManager=getActivity（）.getSupportFragmentManager（）；
FragmentTransaction FragmentTransaction=fragmentManager.beginTransaction（）；
songScreen.setArguments（bundle）；
fragmentTransaction.replace（R.id.layoutCM，
歌幕，
songScreen.getTag（））.commit（）；
}
公共音乐（）{
上下文=getContextOfApplication（）；
ContentResolver ContentResolver=context.getContentResolver（）；
Uri songUri=MediaStore.Audio.Media.EXTERNAL\u CONTENT\u Uri；
Cursor-songcursor=contentResolver.query（songUri，null，null，null）；
if（songcursor！=null&&songcursor.moveToFirst（））{
int-songId=songcursor.getColumnIndex（MediaStore.Audio.Media.\u-ID）；
int-songTitle=songcursor.getColumnIndex（MediaStore.Audio.Media.TITLE）；
int songArtist=songcursor.getColumnIndex（MediaStore.Audio.Media.ARTIST）；
int songAlbum=songcursor.getColumnIndex（MediaStore.Audio.Media.ALBUM）；
int songDuration=songcursor.getColumnIndex（MediaStore.Audio.Media.DURATION）；
int-pathSong=songcursor.getColumnIndex（MediaStore.Audio.Media.DATA）；
做{
Long currentId=songcursor.getLong（songId）；
String currentTitle=songcursor.getString（songTitle）；
String currentArtist=songcursor.getString（songArtist）；
String currentAlbum=songcursor.getString（songAlbum）；
Long currentDuration=songcursor.getLong（songDuration）；
String currentPath=songcursor.getString（pathSong）；
添加（新歌（currentId、currentTitle、currentArtister、currentDuration、currentAlbum、currentPath））；
}
while（songcursor.moveToNext（））；
}
返回宋光标；
}
@凌驾
public void onRequestPermissionsResult（int-requestCode、字符串[]权限、int[]grantResults）{
开关（请求代码）{
案例我的许可请求：{
如果（grantResults.length>0&&grantResults[0]==已授予PackageManager.PERMISSION）{
if（ContextCompat.checkSelfPermission（getContext（）），
Manifest.permission.READ_EXTERNAL_STORAGE）==PackageManager.permission_provided）{
accessfiles（）；
}
}
}
}
}
公共无效getNext（歌曲当前歌曲）{
if（songList.contains（currentSong））
{
int position1=songList.indexOf（当前歌曲）；
if（position1>songList.size（））
{
String nextSong=songList。
public AppCompatActivity mActivity;
    @Override
    public void onAttach(Context context) {
        super.onAttach(context);
        this.mActivity = (BaseActivity) context;
    }

((MainActivity)mActivity).playerStart(previousSong, previous);