Android delete firebase data using custom listview

Question

Hello Everyone how i can delete on click item from custom listview. i am unable to delete the firebase data.

Here is the Student Activity where all student will appear in custom listview i want to delete on click

@Override protected void onStart() { super.onStart();

    Query query = databaseReference.orderByChild("type").equalTo("student");
    query.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {

            list.clear();
            for (DataSnapshot dataSnapshot1 : dataSnapshot.getChildren()){

                ModelClass Mod = dataSnapshot1.getValue(ModelClass.class);
                list.add(Mod);

            }
            final CustomAdapterClassStudent adapterClassCompany = new CustomAdapterClassStudent(AllStudents.this , list);
            l1.setAdapter(adapterClassCompany);
            l1.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {


                }
            });

        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });
}

}

Here is my Custom Adapter class extend with Array Adapter

@NonNull
@Override
public View getView(final int position, @Nullable View convertView, @NonNull ViewGroup parent) {
    LayoutInflater inflater = context.getLayoutInflater();

    final View listview = inflater.inflate(R.layout.customadapter , null , true);
    TextView textViewName  = (TextView) listview.findViewById(R.id.textName);
    TextView textViewAdd  = (TextView) listview.findViewById(R.id.textAdd);
    TextView textViewBio  = (TextView) listview.findViewById(R.id.textBio);

    final ModelClass Mod = compniesModel.get(position);
    textViewName.setText(Mod.name);
    textViewAdd.setText(Mod.cgpa);
    textViewBio.setText(Mod.bio);



    return listview;

Here is the ModelClass.. ModelClass contain student and company fields to save in firebase.. check image below

public class ModelClass {


public String name;
public String email;
public String cgpa;
public String age;
public String bio;


public String type;



public String compName;
public String compAdd;
public String compAbout;


public ModelClass(){}

public ModelClass(String name, String email, String cgpa, String age, String bio,String type) {
    this.name = name;
    this.email = email;
    this.cgpa = cgpa;
    this.age = age;
    this.bio = bio;
    this.type = type;
}

public ModelClass(String compName, String compAdd, String compAbout , String type) {
    this.compName = compName;
    this.compAdd = compAdd;
    this.compAbout = compAbout;
    this.type = type;
}

}

Here is the Database Image Click on this

Answer 1

You need to save the user key in your model, so add this :

public String key;

Then you can set the key :

ModelClass Mod = dataSnapshot1.getValue(ModelClass.class);
Mod.key = dataSnapshot1.getKey();

list.add(Mod);

And in your onItemClick you can now remove the current user :

@Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
    ModelClass model = list.get(i);
    list.remove(removePosition);

    databaseReference.child("users").child(model.key).removeValue();
}

NOTE

You should use childAdded event to not reload all your list when you remove a user.

You should also init your adapter only one time. In your completion update the list and call notifyDataChanged().