-1
줄에서 시작하는 DessertAdapter 클래스에서 널 포인터 예외 오류가 계속 발생합니다. holder.mName.setText(dessert.getName()); 나는 알고있는 모든 방법을 시도했지만 여전히 동일한 오류가 발생합니다. 여기 는 디저트 객체에 데이터를 저장하는 클래스 Adapter 클래스 다음null 개체 참조에서 널 포인터 예외
public class DessertAdapter extends RecyclerView.Adapter<DessertAdapter.DessertVh> {
private List<Dessert> desserts = new ArrayList<>();
private static final int VIEW_TYPE_EMPTY_LIST_PLACEHOLDER = 0;
private static final int VIEW_TYPE_OBJECT_VIEW = 1;
private Context context;
@Override
public int getItemViewType(int position) {
if (desserts.isEmpty()) {
return VIEW_TYPE_EMPTY_LIST_PLACEHOLDER;
} else {
return VIEW_TYPE_OBJECT_VIEW;
}
}
public DessertAdapter(Context context,List<Dessert> desserts) {
this.context = context;
this.desserts = desserts;
}
// TODO: another placeholder stuff here
@Override
public DessertVh onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater inflater = LayoutInflater.from(parent.getContext());
View view = inflater.inflate(R.layout.item_dessert, parent, false);
return new DessertAdapter.DessertVh(view);
}
@Override
public void onBindViewHolder(DessertVh holder, int position) {
Dessert dessert = desserts.get(position);
System.out.println(position);
holder.mName.setText(dessert.getName());
holder.mDescription.setText(dessert.getDescription());
holder.mFirstLetter.setText(String.valueOf(dessert.getFirstLetter()));
holder.mPrice.setText(String.valueOf(dessert.getAmount()));
}
@Override
public int getItemCount() {
return desserts == null ? 0 : desserts.size();
}
public static class DessertVh extends RecyclerView.ViewHolder {
private TextView mName;
private TextView mPrice;
private TextView mDescription;
private TextView mFirstLetter;
public DessertVh(View itemView) {
super(itemView);
mName = (TextView) itemView.findViewById(R.id.txt_name);
mPrice = (TextView) itemView.findViewById(R.id.txt_price);
mDescription = (TextView) itemView.findViewById(R.id.txt_desc);
mFirstLetter = (TextView) itemView.findViewById(R.id.txt_firstletter);
}
}
입니다 여기
public class AddGigActivity extends AppCompatActivity {
private static String TAG = "AddGigActivity";
private ImageButton saveBtn;
private EditText gigName, gigDescrip, gigAmount;
private String userID;
private FirebaseDatabase mFirebaseDatabase;
private FirebaseAuth mAuth;
private FirebaseAuth.AuthStateListener mAuthStateListener;
private DatabaseReference myRef;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_gig);
gigName = (EditText)findViewById(R.id.gig_name);
gigDescrip = (EditText)findViewById(R.id.gig_description);
gigAmount = (EditText) findViewById(R.id.gig_amnt);
saveBtn = (ImageButton) findViewById(R.id.mybtn_add);
mAuth = FirebaseAuth.getInstance();
mFirebaseDatabase = FirebaseDatabase.getInstance();
myRef = FirebaseDatabase.getInstance().getReference();
FirebaseUser user = mAuth.getCurrentUser();
userID = user.getUid();
saveBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
AddGig();
}
});
}
// real-time adding to the firebase database
private void AddGig(){
String name = gigName.getText().toString();
String descrip = gigDescrip.getText().toString();
String amount = gigAmount.getText().toString();
if((!TextUtils.isEmpty(name))&&(!TextUtils.isEmpty(descrip) && (!TextUtils.isEmpty(amount)))){
FirebaseUser user = mAuth.getCurrentUser();
userID = user.getUid();
String id = myRef.push().getKey();
Dessert dessert = new Dessert(name, descrip, amount);
// myRef.child(id).setValue(dessert);
myRef.child("users").child(userID).child("Gig posts").child(id).setValue(dessert);
Toast.makeText(this, "Posted! ",Toast.LENGTH_LONG).show();
finish();
// you can still sprlit these to check for each text field
}else{
Toast.makeText(this, "One or more field(s) missing!",Toast.LENGTH_LONG).show();
}
}
되고 재활용보기에 중포 기지에서 데이터를 표시하는 주요 활동 코드 :
public static class FeedsFragment extends Fragment {
int color;
public FeedsFragment() {
}
@SuppressLint("ValidFragment")
public FeedsFragment(int color) {
this.color = color;
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.dummy_fragment, container, false);
final RecyclerView recyclerView = (RecyclerView) view.findViewById(R.id.dummyfrag_scrollableview);
final FrameLayout frameLayout = (FrameLayout) view.findViewById(R.id.dummyfrag_bg);
frameLayout.setBackgroundColor(color);
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity().getBaseContext());
recyclerView.setLayoutManager(linearLayoutManager);
recyclerView.setHasFixedSize(true);
final List<Dessert> dessertList;
dessertList = new ArrayList<>();
//dessertList = new Dessert(context,"");
final String curtUserId = FirebaseAuth.getInstance().getCurrentUser().getUid();
DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
// DatabaseReference mDatabaseGig = rootRef.child("users").child(curtUserId).child("Gig posts");
final String id = rootRef.push().getKey();
final DessertAdapter adapter = new DessertAdapter(getContext(), dessertList);
recyclerView.setAdapter(adapter);
rootRef.addValueEventListener(new com.google.firebase.database.ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
dessertList.clear();
for(DataSnapshot gigSnapshot: dataSnapshot.getChildren()){
Dessert dessert = gigSnapshot
.child("users")
.child(curtUserId)
.child("Gig posts")
.child(id).getValue(Dessert.class);
dessertList.add(dessert);
adapter.notifyDataSetChanged();
}
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
// possible to put progress dialogue
return view;
}
}
제발 코드를 작성하고 교정 해 주시겠습니까? 고맙습니다.
[NullPointerException이란 무엇이며 어떻게 수정합니까?] (https://stackoverflow.com/questions/218384/what-is-a-nullpointerexception-and-how-do-i-fix) -it) – ADM
'dessertList = new ArrayList <>(); '목록에 데이터를 추가하고 있습니까? – gvmani
레이아웃을 추가하십시오 'item_dessert' –