我刚接触到android。在我的音乐应用程序中，我试图显示专辑封面，但它没有显示它。我不知道这是什么问题。请告诉我如何做到这一点。无法在互联网上找到。
public class BlankFragment2 extends Fragment {
private ArrayList<songInfo> _songs = new ArrayList<songInfo>();
RecyclerView recyclerView;
SeekBar seekBar;
public songAdapter songAdapter1;
ImageView album_art;
MediaPlayer mediaPlayer;
private Handler myHandler = new Handler();
byte[] art;
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private BlankFragment.OnFragmentInteractionListener mListener;
public BlankFragment2() {
// Required empty public constructor
}
// TODO: Rename and change types and number of parameters
public static BlankFragment newInstance(String param1, String param2) {
BlankFragment fragment = new BlankFragment();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView= inflater.inflate(R.layout.fragment_blank_fragment2, container, false);
recyclerView = (RecyclerView)rootView. findViewById(R.id.recyclerView);
seekBar = (SeekBar) rootView.findViewById(R.id.seekBar);
songAdapter1 = new songAdapter(getActivity(),_songs);
recyclerView.setAdapter(songAdapter1);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(recyclerView.getContext(),
linearLayoutManager.getOrientation());
recyclerView.setLayoutManager(linearLayoutManager);
recyclerView.addItemDecoration(dividerItemDecoration);
songAdapter1.setOnItemClickListener(new songAdapter.OnItemClickListener() {
public void onItemClick(RecyclerView.ViewHolder holder, View view, final songInfo obj, int position) {
if(mediaPlayer.isPlaying()){
mediaPlayer.stop();
mediaPlayer.reset();
mediaPlayer.release();
mediaPlayer = null;
}else {
Runnable runnable = new Runnable() {
@Override
public void run() {
try {
mediaPlayer = new MediaPlayer();
mediaPlayer.setDataSource(obj.getSongUrl());
mediaPlayer.prepareAsync();
mediaPlayer.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
@Override
public void onPrepared(MediaPlayer mp) {
mp.start();
seekBar.setProgress(0);
seekBar.setMax(mediaPlayer.getDuration());
Log.d("Prog", "run: " + mediaPlayer.getDuration());
}
});
}catch (Exception e){}
}
};
myHandler.postDelayed(runnable,100);
}
}
});
checkUserPermission();
Thread t = new runThread();
t.start();
return rootView;
}
public class runThread extends Thread {
@Override
public void run() {
while (true) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
Log.d("Runwa", "run: " + 1);
if (mediaPlayer != null) {
seekBar.post(new Runnable() {
@Override
public void run() {
seekBar.setProgress(mediaPlayer.getCurrentPosition());
}
});
Log.d("Runwa", "run: " + mediaPlayer.getCurrentPosition());
}
}
}
}
private void checkUserPermission(){
if(Build.VERSION.SDK_INT>=23){
if(ActivityCompat.checkSelfPermission(getContext(), Manifest.permission.READ_EXTERNAL_STORAGE)
!= PackageManager.PERMISSION_GRANTED){
requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},123);
return;
}
}
loadSongs();
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
switch (requestCode){
case 123:
if (grantResults[0] == PackageManager.PERMISSION_GRANTED){
loadSongs();
}else{
Toast.makeText(getContext(), "Permission Denied", Toast.LENGTH_SHORT).show();
checkUserPermission();
}
break;
default:
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
}
}
private void loadSongs() {
MediaMetadataRetriever metaRetriver = new MediaMetadataRetriever();
Uri uri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
String selection = MediaStore.Audio.Media.IS_MUSIC + "!=0";
Cursor cursor = getContext().getContentResolver().query(uri, null, selection, null, null);
if (cursor != null) {
if (cursor.moveToFirst()) {
do {
String name = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DISPLAY_NAME));
String artist = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.ARTIST));
String url = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DATA));
try {
String pathId = cursor.getString(Integer.parseInt(url));
metaRetriver.setDataSource(pathId);
Log.d(this.getClass().getName(), "path id=" + pathId);
art = metaRetriver.getEmbeddedPicture();
BitmapFactory.Options opt = new BitmapFactory.Options();
opt.inSampleSize = 2;
Bitmap songImage = BitmapFactory.decodeByteArray(art, 0, art.length, opt);
album_art.setImageBitmap(songImage);
} catch (Exception e) {
// album_art.setBackgroundColor(Color.GRAY);
songInfo s = new songInfo(name, artist, url);
_songs.add(s);
}
}
while (cursor.moveToNext());
cursor.close();
songAdapter1 = new songAdapter(getActivity(), _songs);
}
}
}
// TODO: Rename method, update argument and hook method into UI event
public void onButtonPressed(Uri uri) {
if (mListener != null) {
mListener.onFragmentInteraction(uri);
}
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (BlankFragment.OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
@Override
public void onDetach() {
super.onDetach();
mListener = null;
}
public interface OnFragmentInteractionListener {
void onFragmentInteraction(Uri uri);
}
}
adapter
public class songAdapter extends RecyclerView.Adapter<songAdapter.SongHolder> {
private ArrayList<songInfo> _songs = new ArrayList<>();
private Context context;
private OnItemClickListener mOnItemClickListener;
public songAdapter(Context context, ArrayList<songInfo> songs) {
this.context = context;
this._songs = songs;
}
public interface OnItemClickListener {
void onItemClick(RecyclerView.ViewHolder holder, View view, songInfo obj, int position);
// void onItemClick(Button b, View view, songInfo obj, int position);
}
public void setOnItemClickListener(final OnItemClickListener mItemClickListener) {
this.mOnItemClickListener = mItemClickListener;
}
@Override
public SongHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
View myView = LayoutInflater.from(context).inflate(R.layout.card,viewGroup,false);
return new SongHolder(myView);
}
@Override
public void onBindViewHolder(final SongHolder songHolder, final int i) {
final songInfo s = _songs.get(i);
songHolder.tvSongName.setText(_songs.get(i).getSongName());
songHolder.tvSongArtist.setText(_songs.get(i).getArtistName());
setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(RecyclerView.ViewHolder holder, View view, songInfo obj, int position) {
if (mOnItemClickListener != null) {
mOnItemClickListener.onItemClick(songHolder, view, s, i);
}
}
});
}
@Override
public int getItemCount() {
return _songs.size();
}
public class SongHolder extends RecyclerView.ViewHolder {
TextView tvSongName,tvSongArtist;
ImageView album_art;
public SongHolder(View itemView) {
super(itemView);
tvSongName = (TextView) itemView.findViewById(R.id.songName);
tvSongArtist = (TextView) itemView.findViewById(R.id.artistName);
album_art = (ImageView) itemView.findViewById(R.id.albumArt);
}
}
}
这是我的日志。
没有连接适配器;跳过布局01-11 00：30：16.000 8631-8665 / com.example.murarilal.atry D / Runwa：运行：1 01-11 00：30：16.002 8631-8631 / com.example.murarilal.atry I / Choreographer： 跳过63帧！应用程序可能在其上做了太多工作 主线程。 01-11 00：30：16.030 8631-8664 / com.example.murarilal.atry D / EGL_emulation：eglMakeCurrent
答案 0 :(得分：0)
在您加载未绑定到recyclerView
所以不要创建新实例
songAdapter1 = new songAdapter(getActivity(), _songs);
调用适配器的notifyDataSetChanged()方法，如下所示：
songAdapter1.notifyDataSetChanged()
或者您只需删除songAdapter1字段即可通过调用
recyclerView.getAdapter().notifyDataSetChanged()