我在ListView中检索歌曲列表但是当应用程序在模拟器上运行时，屏幕为空白。我没有得到它只显示以下错误的歌曲列表。
musicmania E / RecyclerView：没有连接适配器;跳过布局01-04 05：33：07.534 28855-28855 / com.example.murarilal.musicmania
E / RecyclerView：没有连接适配器;跳过布局01-04 05：33：07.540 28855-28855 / com.example.murarilal.musicmania I / Choreographer：跳过48帧！该应用程序可能也在做 在其主要线程上做了很多工作。 01-04 05:33：07.566 28855-28874 / com.example.murarilal.musicmania D / EGL_emulation： eglMakeCurrent：0x9e2050c0：ver 2 0（tinfo 0x9e2032d0）01-04 05：33：07.903 28855-28862 / com.example.murarilal.musicmania W / zygote：暂停所有线程：17.506ms
SongsTab活动
public class SongsTab extends Fragment {
ArrayList<songInfo> _songs = new ArrayList<songInfo>();
RecyclerView recyclerView;
SeekBar seekBar;
songAdapter songAdapter1;
MediaPlayer mediaPlayer;
Handler myHandler = new Handler();
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.songs, container, false);
recyclerView = (RecyclerView)v. findViewById(R.id.recyclerView);
seekBar = (SeekBar) v.findViewById(R.id.seekBar);
songAdapter1 = new songAdapter(getActivity(),_songs);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(recyclerView.getContext(),
linearLayoutManager.getOrientation());
recyclerView.setLayoutManager(linearLayoutManager);
recyclerView.setAdapter(songAdapter1);
recyclerView.addItemDecoration(dividerItemDecoration);
return v;
}
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
loadSongs();
// add your code here which executes after the execution of onCreateView() method.
songAdapter1.setOnItemClickListener(new songAdapter.OnItemClickListener() {
@Override
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());
}
});
Log.i("devesh","vikas");
}catch (Exception e){}
}
};
myHandler.postDelayed(runnable,100);
}
}
});
checkUserPermission();
Thread t = new runThread();
t.start();
}
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(getActivity(), 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);
}
}
public void loadSongs(){
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));
songInfo s = new songInfo(name,artist,url);
_songs.add(s);
songAdapter1.notifyDataSetChanged();
recyclerView.setAdapter(songAdapter1);
}while (cursor.moveToNext());
}
cursor.close();
}
}
}
MainActivity
public class MainActivity extends AppCompatActivity {
public ViewPagerAdapter pagerAdapter;
private ViewPager mViewPager;
private Toolbar toolbar;
private TabLayout tabLayout;
public static View rootView;
public static int tabNo;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
pagerAdapter = new ViewPagerAdapter(getSupportFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.container);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
mViewPager.setAdapter(pagerAdapter);
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
tabNo = tab.getPosition();
mViewPager.setCurrentItem(tabNo);//setting current selected item over viewpager
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public static class PlaceholderFragment extends Fragment {
private static final String ARG_SECTION_NUMBER = "section_number";
public PlaceholderFragment() {
}
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// View rootView;
switch (getArguments().getInt(ARG_SECTION_NUMBER))
{
case 1: {
rootView = inflater.inflate(R.layout.songs, container, false);
break;
}
case 2: {
rootView = inflater.inflate(R.layout.album, container, false);
break;
}
case 3: {
rootView = inflater.inflate(R.layout.genres, container, false);
break;
}
case 4: {
rootView = inflater.inflate(R.layout.artist, container, false);
break;
}
}
return rootView;
}
}
}
答案 0 :(得分：0)
你不能使用Thread.sleep，而是使用处理程序或倒计时器
答案 1 :(得分：0)
我相信loadSongs（）是在主线程中发生的，它正在进行
songAdapter1.notifyDataSetChanged();
recyclerView.setAdapter(songAdapter1);
你不应该一次又一次地setAdapater而只是notifyDataSetChange