无法使用QR码扫描程序的handleResult（）方法从Firebase读取

Question

我希望变量一，二和三能够在扫描QR码时从我的数据库中读取但我不能让它们显示在Builder.setMessage（）行中...我试过调用displayDeals （）方法在几个地方但没有工作...

package com.example.darren.offerapp;

import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.auth.FirebaseUser;
import com.google.firebase.database.ChildEventListener;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
import com.google.zxing.Result;

import me.dm7.barcodescanner.zxing.ZXingScannerView;

public class PopUpPage extends AppCompatActivity implements ZXingScannerView.ResultHandler {

    private ZXingScannerView mScannerView;

    private FirebaseAuth firebaseAuth;
    private FirebaseUser firebaseUser;
    private DatabaseReference databaseReference;
    private String dealID;
    private Deals_Information deals_information;
    private String one = "";
    private String two = "";
    private String three = "";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_pop_up_page);

        //stuff for popup window
            DisplayMetrics dm = new DisplayMetrics();
            getWindowManager().getDefaultDisplay().getMetrics(dm);
            int width = dm.widthPixels;
            int height = dm.heightPixels;
            getWindow().setLayout((int)(width*0.8), (int)(height*0.6));

        //calling the method which will pull the deals from the database
        //displaySuggestion();

        firebaseAuth = FirebaseAuth.getInstance();
        firebaseUser = firebaseAuth.getCurrentUser();
        databaseReference = FirebaseDatabase.getInstance().getReference();
        dealID = firebaseUser.getUid();

        displayDeals();
    }

    public void displayDeals(){

        databaseReference.child("FruitDeals").child(dealID).addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(DataSnapshot dataSnapshot, String s) {
                deals_information = dataSnapshot.getValue(Deals_Information.class);
                one = deals_information.getDeal();
                two = deals_information.getPrice();
                three = deals_information.getAisleNum();
            }

            @Override
            public void onChildChanged(DataSnapshot dataSnapshot, String s) {

            }

            @Override
            public void onChildRemoved(DataSnapshot dataSnapshot) {

            }

            @Override
            public void onChildMoved(DataSnapshot dataSnapshot, String s) {

            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });

    }

    public void onClick(View v){
        mScannerView = new ZXingScannerView(this);
        setContentView(mScannerView);
        mScannerView.setResultHandler(this);
        mScannerView.startCamera();
    }
    @Override
    protected void onPause() {
        super.onPause();
        mScannerView.stopCamera();
    }

    @Override
    public void handleResult(Result result) {

        //do anything with result here
        Log.w("handleResult", result.getText());
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("Your Deal");
        builder.setMessage("Offer: " + one + "\r\n\r\nPrice: " + two + "\r\n\r\nAisle Number: " + three + "");
        AlertDialog alertDialog = builder.create();
        alertDialog.show();

        //resume scanning
        //mScannerView.resumeCameraPreview(this); //uncomment out this line when you want to scan again
    }
}

Deals_Information类在这里：

package com.example.darren.offerapp;

公共类Deals_Information {

private String deal;
private String price;
private String aisleNum;


//getters and setters
public String getPrice() {
    return price;
}

public void setPrice(String price) {
    this.price = price;
}

public String getAisleNum() {
    return aisleNum;
}

public void setAisleNum(String aisleNum) {
    this.aisleNum = aisleNum;
}

public String getDeal() {
    return deal;
}

public void setDeal(String deal) {
    this.deal = deal;
}

public Deals_Information(){

}

public Deals_Information(String deal, String price, String aisleNum)
{
    this.deal = deal;
    this.price = price;
    this.aisleNum = aisleNum;
}

}

This is the image I am talking about in my last comment