使用Firebase适配器填充ListView

Question

I'm receiving these errors when I tried to populate a list view with firebase adapter using firebase UI

com.google.firebase.database.DatabaseException: Failed to convert value of type java.util.HashMap to String com.google.firebase.database.DatabaseException: Class java.util.HashMap has generic type parameters, please use GenericTypeIndicator instead

Here Is the code

     DatabaseReference ref = FirebaseDatabase.getInstance().getReference();
     DatabaseReference a = ref.child("info");

        final FirebaseListAdapter<String> adapter =
              new FirebaseListAdapter<String>(this,String.class,android.R.layout.simple_list_item_1,a) {
                  @Override
                  protected void populateView(View v, String model, int position) {

                      TextView text = (TextView) findViewById(android.R.id.text1);
                      text.setText(model);

                  }

here is an example of json data

 "info" : {
   "KSTUJILdwPN305Fs7ujhga4knlG3" : {
     "File Info" : {
       "-JFRkA855rfOU7GtcK4" : {
         "Name" : "John",
         "Adress" : "Test Adress",
         "Favourite_food" : "Bread",
       },

Answer 1

info node does not refer to your data model. It may contain children nodes. So to reach the model, you should use a reference like this.

 DatabaseReference a = ref.child("info").child(info_id).child("File Info").child(file_id); 

and you should have a FileInfo model instead of String model to use in

populateView(View v, FileInfo model, int position):

and model

public class FileInfo {

private String Name;
private String Adress;
private String Favourite_food;

public FileInfo() {
}

public FileInfo(String Name, String Adress, String Favourite_food) {
    this.Name = Name;
    this.Adress = Adress;
    this.Favourite_food = Favourite_food;
}

public String getName() {
    return Name;
}

public void setName(String Name) {
    this.Name = Name;
}

public String getAdress() {
    return Adress;
}

public void setAdress(String Adress) {
    this.Adress = Adress;
}

public String getFavourite_food() {
    return Favourite_food;
}

public void setFavourite_food(String Favourite_food) {
    this.Favourite_food = Favourite_food;
}

}

Answer 2

final FirebaseListAdapter<String> adapter = new FirebaseListAdapter<String>(this,String.class,android.R.layout.simple_list_item_1,a)

public FirebaseListAdapter(Activity activity,
               java.lang.Class<T> modelClass,
               int modelLayout,
               com.firebase.client.Firebase ref)

modelClass - Firebase will marshall the data at a location into an instance of a class that you provide

replace the constructor's 2nd parameter (String.class) with a POJO with the fields from info (name, address, favouriteFood)

FirebaseListAdapter

Edit:

You should also use getters in the populateView method