我收到错误，说没有适配器附加跳过布局。当模拟器运行时，列表不会出现。请帮助。我无法看到列表中的任何内容。屏幕显示为空白。活动中的其他项目是appearing.i已经在网上看到了几乎所有的答案，但没有得到任何解决方案。当我试图在其他标签中制作列表视图时，我得到了列表。
这是 songsTab活动
public class SongsTab extends Fragment {
private ArrayList<songInfo> songs = new ArrayList<songInfo>();
RecyclerView recyclerView;
SeekBar seekBar;
songAdapter songAdapter1;
MediaPlayer mediaPlayer;
Cursor cursor;
private 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(songs, getActivity());
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());
DividerItemDecoration dividerItemDecoration = new DividerItemDecoration(recyclerView.getContext(),
linearLayoutManager.getOrientation());
recyclerView.addItemDecoration(dividerItemDecoration);
recyclerView.setLayoutManager(linearLayoutManager);
recyclerView.setAdapter(songAdapter1);
solved();
checkUserPermission();
Thread t = new runThread();
t.start();
return v;
}
public void solved() {
songAdapter1.setOnitemClickListener(new songAdapter.OnitemClickListener() {
@Override
public void onItemclick(songAdapter.ViewHolder holder, View v, 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.getSongPath());
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);
}
}
});
}
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(){
Uri uri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
String selection = MediaStore.Audio.Media.IS_MUSIC+"!=0";
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 SongPath = cursor.getString(cursor.getColumnIndex(MediaStore.Audio.Media.DATA));
songInfo s = new songInfo(name, artist, SongPath);
songs.add(s);
} while (cursor.moveToNext());
}
cursor.close();
songAdapter1 = new songAdapter(songs, getActivity());
}
}
}
这是我的适配器
public class songAdapter extends RecyclerView.Adapter<songAdapter.ViewHolder> {
ArrayList<songInfo> songs;
Context context;
OnitemClickListener onitemClickListener;
public songAdapter(ArrayList<songInfo> songs, Context context) {
this.songs = songs;
this.context = context;
}
public interface OnitemClickListener{
void onItemclick(ViewHolder holder, View v, songInfo obj, int position);
}
public void setOnitemClickListener(OnitemClickListener onitemClickListener)
{
this.onitemClickListener=onitemClickListener;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View mView= LayoutInflater.from(context).inflate(R.layout.card,parent,false);
return new ViewHolder(mView);
}
@Override
public void onBindViewHolder(final ViewHolder holder, final int position) {
final songInfo song = songs.get(position);
holder.songName.setText(songs.get(position).getSongName());
holder.artistName.setText(songs.get(position).getArtistName());
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if(onitemClickListener!=null)
{
onitemClickListener.onItemclick(holder,view,song,position);
}
}
});
}
@Override
public int getItemCount() {
return songs.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
TextView songName,artistName;
public ViewHolder(View itemView) {
super(itemView);
songName=(TextView)itemView.findViewById(R.id.songName);
artistName=(TextView)itemView.findViewById(R.id.artistName);
}
}
}
主要活动
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;
}
}
}
recyclerView xml
<?xm version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<ScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/scrollView">
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="150dp"
android:id="@+id/recyclerView"
android:layout_alignParentTop="true"
android:layout_alignParentStart="true"
android:layout_above="@+id/seekBar" />
</ScrollView>
<SeekBar
android:layout_width="match_parent"
android:layout_height="30dp"
android:id="@+id/seekBar"
android:layout_alignParentBottom="true"
android:layout_alignParentStart="true"
android:layout_marginBottom="37dp"
android:indeterminate="false" />
</RelativeLayout>
this is cardView
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
app:cardBackgroundColor="#f5fffa"
android:layout_height="wrap_content">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="20dp"
android:orientation="horizontal">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"
android:layout_gravity="center"
android:orientation="vertical">
<TextView
android:id="@+id/songName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="20sp"
android:text="Shape of you"
android:maxLines="1"/>
<TextView
android:id="@+id/artistName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="15sp"
android:text="Ed Sheeran"
android:maxLines="1"/>
</LinearLayout>
</LinearLayout>
</android.support.v7.widget.CardView>
</LinearLayout>
mainActivity xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.example.murarilal.musicmania.MainActivity">
<android.support.design.widget.AppBarLayout
android:id="@+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="@dimen/appbar_padding_top"
android:theme="@style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="@style/AppTheme.PopupOverlay">
</android.support.v7.widget.Toolbar>
<android.support.design.widget.TabLayout
android:id="@+id/tabs"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>
答案 0 :(得分：0)
请勿在{{1}}内再次初始化songAdapter1。
在loadSongs() class：
songAdapter在 public void notifySongAdded(ArrayList<songInfo> songs) {
this.songs = songs;
notifyDataSetChanged();
}
内添加歌曲后致电songAdapter1.notifySongAdded(songs);。