Can not read data from firebase as List in android - firebase

Question

I read many articles but still my problem is continuing, while fetching data from firebase as list. could you please help me on this.
Error: com.google.firebase.database.DatabaseException: Can't convert
object of type java.lang.String to type SubCategoryLoad Object
Firebase database image
--> Loading data from firebase:
mSubCategoryDatabaseRef = FirebaseDatabase.getInstance().getReference("user_post_add_database_ref").child("yeswanth599").child(mCategoryNameReceive);
mSubCategoryDatabaseRef.addValueEventListener(new ValueEventListener() {
#Override
public void onDataChange(#NonNull DataSnapshot dataSnapshot) {
for (DataSnapshot postSnapshot : dataSnapshot.getChildren()) {
GenericTypeIndicator<Map<String,SubCategoryLoad>> genericTypeIndicator=new GenericTypeIndicator<Map<String,SubCategoryLoad>>(){};
(-->Error Showing in this Line) Map<String,SubCategoryLoad> map=(Map<String, SubCategoryLoad>)postSnapshot.getValue(genericTypeIndicator);
assert map != null;
mSubCategoryLoad=new ArrayList<>(map.values());
}
mSubCategoryAdapter = new SubCategoryDisplayAdapter(getContext(), mSubCategoryLoad);
mSubCategoryRecyclerView.setAdapter(mSubCategoryAdapter);
mSubCategoryProgressCircle.setVisibility(View.INVISIBLE);
}
#Override
public void onCancelled(#NonNull DatabaseError databaseError) {
Toast.makeText(getContext(), databaseError.getMessage(), Toast.LENGTH_SHORT).show();
mSubCategoryProgressCircle.setVisibility(View.INVISIBLE);
}
});
--> SubCategoryLoad.Class
public class SubCategoryLoad {
private String mUserPostAddress;
private String mUserPostBusinessEndTime;
private String mUserPostBusinessSelectedCity;
private String mUserPostBusinessSelectedCountry;
private String mUserPostBusinessStartTime;
private String mUserPostCategory;
private String mUserPostEmail;
private List<UserPostAdsImages> mUserPostImages;
private String mUserPostName;
private String mUserPostPhonenumber;
private List<UserPostAdsLanguages> mUserPostSupportingLanguage;
private String mUserPostWebsite;
public SubCategoryLoad() {
//empty constructor needed
}
public SubCategoryLoad(String userPostAddress, String userPostBusinessEndTime,
String userPostBusinessSelectedCity, String userPostBusinessSelectedCountry,
String userPostBusinessStartTime, String userPostCategory,
String userPostEmail, List<UserPostAdsImages> userPostImages,
String userPostName, String userPostPhonenumber,
List<UserPostAdsLanguages> userPostSupportingLanguage, String userPostWebsite
) {
mUserPostAddress = userPostAddress;
mUserPostBusinessEndTime = userPostBusinessEndTime;
mUserPostBusinessSelectedCity = userPostBusinessSelectedCity;
mUserPostBusinessSelectedCountry = userPostBusinessSelectedCountry;
mUserPostBusinessStartTime = userPostBusinessStartTime;
mUserPostCategory = userPostCategory;
mUserPostEmail = userPostEmail;
mUserPostImages = userPostImages;
mUserPostName = userPostName;
mUserPostPhonenumber = userPostPhonenumber;
mUserPostSupportingLanguage = userPostSupportingLanguage;
mUserPostWebsite = userPostWebsite;
}
public void setUserPostAddress(String userPostAddress) {
this.mUserPostAddress = userPostAddress;
}
public void setUserPostBusinessEndTime(String userPostBusinessEndTime) {
this.mUserPostBusinessEndTime = userPostBusinessEndTime;
}
public void setUserPostBusinessSelectedCity(String userPostBusinessSelectedCity) {
this.mUserPostBusinessSelectedCity = userPostBusinessSelectedCity;
}
public void setUserPostBusinessSelectedCountry(String userPostBusinessSelectedCountry) {
this.mUserPostBusinessSelectedCountry = userPostBusinessSelectedCountry;
}
public void setUserPostBusinessStartTime(String userPostBusinessStartTime) {
this.mUserPostBusinessStartTime = userPostBusinessStartTime;
}
public void setUserPostCategory(String userPostCategory) {
this.mUserPostCategory = userPostCategory;
}
public void setUserPostEmail(String userPostEmail) {
this.mUserPostEmail = userPostEmail;
}
public void setUserPostImages(List<UserPostAdsImages> userPostImages) {
this.mUserPostImages = userPostImages;
}
public void setUserPostName(String userPostName) {
this.mUserPostName = userPostName;
}
public void setUserPostPhonenumber(String userPostPhonenumber) {
this.mUserPostPhonenumber = userPostPhonenumber;
}
public void setUserPostSupportingLanguage(List<UserPostAdsLanguages> userPostSupportingLanguage) {
this.mUserPostSupportingLanguage = userPostSupportingLanguage;
}
public void setUserPostWebsite(String userPostWebsite) {
this.mUserPostWebsite = userPostWebsite;
}
public String getUserPostAddress() {
return mUserPostAddress;
}
public String getUserPostBusinessEndTime() {
return mUserPostBusinessEndTime;
}
public String getUserPostBusinessSelectedCity() {
return mUserPostBusinessSelectedCity;
}
public String getUserPostBusinessSelectedCountry() {
return mUserPostBusinessSelectedCountry;
}
public String getUserPostBusinessStartTime() {
return mUserPostBusinessStartTime;
}
public String getUserPostCategory() {
return mUserPostCategory;
}
public String getUserPostEmail() {
return mUserPostEmail;
}
public List<UserPostAdsImages> getUserPostImages() {
return mUserPostImages;
}
public String getUserPostName() {
return mUserPostName;
}
public String getUserPostPhonenumber() {
return mUserPostPhonenumber;
}
public List<UserPostAdsLanguages> getUserPostSupportingLanguage() {
return mUserPostSupportingLanguage;
}
public String getUserPostWebsite() {
return mUserPostWebsite;
}
}
--> SubCategoryDisplayAdapter.class
SubCategoryLoad subCategoryLoadCurrent = mSubCategoryLoad.get(position);
holder.mSubCategoryAdsTitle.setText(subCategoryLoadCurrent.getUserPostName());
holder.mSubCategoryAdsSupportingLanguagesList.setText("English,Japanese");
//Log.i(TAG, "message:"+subCategoryLoadCurrent.getUserPostImages().get(0).getUserPostImageList());
Glide.with(mContext)
.load(subCategoryLoadCurrent.getUserPostImages().get(0).getUserPostImageList())
.into(holder.mSubCategoryAdsImage);
Thanks & Regards,
Yeswanth.

Answer 1

I used to have the same issue with my parsing and the problem was instead of a list of custom objects i was supposed to be using a Map like this
private Map<String,Boolean>
That field in Firebase contains a key and a state (True or False).
Also you can check the code on the docs to see how they parse these objects.
https://firebase.google.com/docs/database/android/read-and-write?authuser=0#read_data_once