1
gegossen wird ich eine ArrayList von Objekten auf Firebase-Datenbank laden, und wenn ich die ArrayList herunterladen und in ArrayList Wert setzen, bekomme ich Meldung „HashMap nicht java.util.ArrayList gegossen werden kann“. Aber ich lade ArrayList, laden Sie ArrayList, setzen Sie in ArrayList Wert, also warum sagt der Fehler HashMap?HashMap kann nicht auf Arraylist
public class TileContentFragment extends Fragment {
ArrayList<Item> mItems=new ArrayList<>();
private FirebaseAuth mFirebaseAuth;
private FirebaseUser mFirebaseUser;
private DatabaseReference mDatabase;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
// Initialize Firebase Auth and Database Reference
mFirebaseAuth = FirebaseAuth.getInstance();
mFirebaseUser = mFirebaseAuth.getCurrentUser();
mDatabase = FirebaseDatabase.getInstance().getReference();
RecyclerView recyclerView = (RecyclerView) inflater.inflate(R.layout.recycler_view, container, false);
ContentAdapter adapter = new ContentAdapter(recyclerView.getContext(),mItems);
recyclerView.setAdapter(adapter);
recyclerView.setHasFixedSize(true);
// Set padding for Tiles
int tilePadding = getResources().getDimensionPixelSize(R.dimen.tile_padding);
recyclerView.setPadding(tilePadding, tilePadding, tilePadding, tilePadding);
recyclerView.setLayoutManager(new GridLayoutManager(getActivity(), 2));
return recyclerView;
}
@Override
public void onStart() {
super.onStart();
mDatabase.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot snapshot) {
if (snapshot.hasChild("ItemsArray")) {
final ValueEventListener userListener = new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
mItems = new ArrayList<>((ArrayList) dataSnapshot.getValue());
}
@Override
public void onCancelled(DatabaseError databaseError) {
Log.w("AppInfo", "onCancelled: ",databaseError.toException());
}
};
mDatabase.child("ItemsArray").addValueEventListener(userListener);
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
}
public static class ViewHolder extends RecyclerView.ViewHolder {
public ImageView picture;
public TextView name;
public ViewHolder(LayoutInflater inflater, ViewGroup parent) {
super(inflater.inflate(R.layout.item_tile, parent, false));
picture = (ImageView) itemView.findViewById(R.id.tile_picture);
name = (TextView) itemView.findViewById(R.id.tile_title);
itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Context context = v.getContext();
Intent intent = new Intent(context, DetailActivity.class);
intent.putExtra(DetailActivity.EXTRA_POSITION, getAdapterPosition());
context.startActivity(intent);
}
});
}
}
/**
* Adapter to display recycler view.
*/
public static class ContentAdapter extends RecyclerView.Adapter<ViewHolder> {
// Set numbers of Tiles in RecyclerView.
private static final int LENGTH = 18;
private final String[] mPlaces;
private ArrayList<Item> mPlacePictures;
public ContentAdapter(Context context,ArrayList<Item> mPlacePictures) {
Resources resources = context.getResources();
mPlaces = resources.getStringArray(R.array.places);
this.mPlacePictures=mPlacePictures;
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
return new ViewHolder(LayoutInflater.from(parent.getContext()), parent);
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
Picasso.with(holder.picture.getContext()).load(mPlacePictures.get(position).getProfilePic()).into(holder.picture);
// holder.picture.setImageDrawable(mPlacePictures[position % mPlacePictures.length]);
holder.name.setText(mPlaces[position % mPlaces.length]);
}
@Override
public int getItemCount() {
return mPlacePictures.size();
}
}
}
public class Item {
private String user;
private String name;
private String desription;
private int price;
private ArrayList<String> url;
private String profilePic;
public Item(){}
public Item(String user,String name, String desription, int price, ArrayList<String> url){
this.user=user;
this.name=name;
this.desription=desription;
this.price=price;
this.url=url;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDesription() {
return desription;
}
public void setDesription(String desription) {
this.desription = desription;
}
public int getPrice() {
return price;
}
public void setPrice(int price) {
this.price = price;
}
public ArrayList<String> getUrl() {
return url;
}
public void setUrl(ArrayList<String> url) {
this.url = url;
}
public String getUser() {
return user;
}
public void setUser(String user) {
this.user = user;
}
public String getProfilePic() {
return profilePic;
}
public void setProfilePic(String profilePic) {
this.profilePic = profilePic;
}
}
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.packtpub.materialdesign4, PID: 713
java.lang.ClassCastException: java.util.ArrayList cannot be cast to java.util.Map
at com.packtpub.materialdesign4.TileContentFragment$1$1.onDataChange(TileContentFragment.java:82)
at com.google.android.gms.internal.zzakg.zza(Unknown Source)
at com.google.android.gms.internal.zzalg.zzcxk(Unknown Source)
at com.google.android.gms.internal.zzalj$1.run(Unknown Source)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5527)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:730)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:620)
DynamiteModule: Local module descriptor class for com.google.firebase.auth not found.
Könnten Sie Ihre 'Item' Klasse posten? –
Ich lege item Klasse, bitte heeelp – bojan