在Android（Spinner）中从Firebase检索数据

Question

数据库

我已经在数据库中检索了该名称并将其存储在微调器中。我想问的是在微调器中选择一个名称后如何检索“名称”的“数字”，然后单击按钮后该数字将如何显示在文本视图中？这是我的代码，它不起作用。

private void getNumber(){
mDatabaseRef.child("Drivers' Info").addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            for(DataSnapshot postSnapshot : dataSnapshot.getChildren()) {
                String name = postSnapshot.child("name").getValue(String.class);
                if (name.equals(sp)) {
                    String j = (String) postSnapshot.child("number").getValue();
                    display_number.setTextSize(26);
                    display_number.setText(j);

                }
            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });


}

我的布局

请帮助我！预先感谢！

Answer 1

以下是我为解决该问题而编写的一段代码中所有为您注释的摘录

        //Create the spinner
                View spinnerView = LayoutInflater.from(prefs.this).inflate(R.layout.activity_custom_spinner,null);
                final Spinner fechasBackupUsuario = spinnerView.findViewById(R.id.spinnerBackup);
                mDatabase.child("Users").child(uid).child("Backup").addValueEventListener(new ValueEventListener() {
                    @Override
                    public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
                        //We create an arraylist to hold the values brought from the database and show them in the spinner
                        lstBackups = new ArrayList<String>();
                        lstBackupsMilis = new ArrayList<String>();

                        for(DataSnapshot snapshot : dataSnapshot.getChildren()){
                            mBackupDates = snapshot.getKey();
                            if(!mBackupDates.contains("UltimoBackup")){
                            long serverDate = Long.parseLong(mBackupDates);
                            String humanDate = convertTimeWithTimeZome(serverDate*1000);
                                Log.e("FirebaseBackup","HumanDate: "+humanDate+" \\n ServerDate: "+mBackupDates);
                                lstBackups.add(humanDate);
                                lstBackupsMilis.add(mBackupDates);
                                int cantBackups = lstBackups.size();
                                Log.e("FirebaseBackups","Cantidad de backups: "+cantBackups);
                            }

                            //Now we populate the spinner with that arraylist
                            final ArrayAdapter<String> backupAdapter = new ArrayAdapter<String>(prefs.this,android.R.layout.simple_spinner_item,lstBackups);
                            backupAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                            fechasBackupUsuario.setAdapter(backupAdapter);


                            //Click event for each spinner element
                            fechasBackupUsuario.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
                                @Override
                                public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
// getting the element when we click
                                    mSelectedBackupDate = lstBackupsMilis.get(i);
                                    Log.e("FirebaseBackup",""+mSelectedBackupDate);

                                    //Here i pass the reference from that value into another snapshot in order to query those values, here you need to get your node id and inside just get your number , name and so on
                                    mDatabase.child("Usuarios").child(uid).child("Backup").child(mSelectedBackupDate).addValueEventListener(new ValueEventListener() {
                                        @Override
                                        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {

                                           //logic to get my data from that specific spinner value


                                            }
                                        }

                                        @Override
                                        public void onCancelled(@NonNull DatabaseError databaseError) {

                                        }
                                    });


                                }

                                @Override
                                public void onNothingSelected(AdapterView<?> adapterView) {

                                }
                            });

                        }

                    }

                    @Override
                    public void onCancelled(@NonNull DatabaseError databaseError) {

                    }
                });

Answer 2

DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference("SmartDab").child("User");

databaseReference.addListenerForSingleValueEvent(new ValueEventListener() {
       @Override
       public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
           List<String > are = new ArrayList<>();

        for (DataSnapshot ds : dataSnapshot.getChildren()) {
            String userType = ds.child("status").getValue().toString();
            switch (userType) {
                case "Teacher":

                    String Name = ds.child("fullname").getValue().toString();
                    are.add(Name);

                    break;

            }
        }
           ArrayAdapter<String> areasAdapter = new ArrayAdapter<String>
                   (giftclass.this, android.R.layout.simple_spinner_item,
                   are);
           areasAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
           spin.setAdapter(areasAdapter);

           spin.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
               @Override
               public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                   String selectedItem = spin.getSelectedItem().toString();

                   Toast.makeText(giftclass.this, "You Select Prof: "+selectedItem, Toast.LENGTH_SHORT).show();



               }

               @Override
               public void onNothingSelected(AdapterView<?> parent) {

               }
           });

       }

       @Override
       public void onCancelled(@NonNull DatabaseError databaseError) {

       }
   });