My App crashes because of Firebase data reading

When I start my app with Android studio it crashes and I get the error:

java.lang.NullPointerException: Attempt to invoke virtual method 'int java.lang.Integer.intValue()' on a null object reference

at main.MainActivity$3.onDataChange(MainActivity.java:151)

I guess it has to to with collecting the data from firebase. But before I had this error I could read data from firebase easily . I am a beginner and totally feel confused with this problem . I looked at other similair problems but still coudnt solve this.

MainActivity:

package main;

import android.app.Dialog;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.CountDownTimer;
import android.preference.PreferenceManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.Window;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

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.Query;
import com.google.firebase.database.ValueEventListener;

import java.math.BigDecimal;

import calebseeling2.click.R;


public class MainActivity extends AppCompatActivity
private Button click_start;
private double money_plus_value = 0;
private TextView number_final;
private static int clicker = 2;
// private int clicker_custom = shop.getClicker();
private TextView yourscore;
private int money_1 = 0;
private ImageView txtclose;
private int value;
private int value_for_score;
private Button btnFollow;
private int value_money;
private static String TAG = "MainActivity";
private FirebaseDatabase database;
private FirebaseDatabase database_for_score;
private SharedPreferences.Editor editor;
private ImageView shop;
private ImageView Highlist;
private TextView money;
private int Key;
private DatabaseReference myRef;
private DatabaseReference myRef_for_score;
private double money_per_click = 1;
private int number;
private int money_2;
private String name;
private static String Name;
private static SharedPreferences your_score;
private static SharedPreferences prefs_money;
private static SharedPreferences click;
private int bigDecimal;
private int value_clicks;
private static SharedPreferences Name_saver;
private TextView timert;
private TextView restart;
private boolean buttonclick = false;
String numberforsave = number + "";


public static int getClicker()
return clicker;



@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
first();

//PreferenceManager initialized


your_score= PreferenceManager.getDefaultSharedPreferences(this.getBaseContext());
prefs_money= PreferenceManager.getDefaultSharedPreferences(this.getBaseContext());
click= PreferenceManager.getDefaultSharedPreferences(this.getBaseContext());
Name_saver = PreferenceManager.getDefaultSharedPreferences(this.getBaseContext());
//initialized database
database_for_score = FirebaseDatabase.getInstance();
myRef_for_score = database_for_score.getReference("Highscore");
database = FirebaseDatabase.getInstance();
myRef = database.getReference(getName());

// Read from the database
myRef_for_score.addValueEventListener(new ValueEventListener()
@Override
public void onDataChange(DataSnapshot dataSnapshot)
// This method is called once with the initial value and again
// whenever data at this location is updated.
if (dataSnapshot.exists())
value = dataSnapshot.getValue(Integer.class);
Log.d(TAG, "Value is: " + value);
else
Toast.makeText(MainActivity.this, "Error!You are not on the database. Please deinstall and reinstall again", Toast.LENGTH_SHORT).show();








@Override
public void onCancelled(DatabaseError error)
// Failed to read value
Log.w(TAG, "Failed to read value.", error.toException());

);
myRef.addValueEventListener(new ValueEventListener()
@Override
public void onDataChange(DataSnapshot dataSnapshot)
// This method is called once with the initial value and again
// whenever data at this location is updated.
if (dataSnapshot.exists())
value_money = dataSnapshot.child("Money").getValue(Integer.class);
Log.d(TAG, "Value is: " + value);
else
Toast.makeText(MainActivity.this, "Error!You are not on the database. Please deinstall and reinstall again", Toast.LENGTH_SHORT).show();








@Override
public void onCancelled(DatabaseError error)
// Failed to read value
Log.w(TAG, "Failed to read value.", error.toException());

);
myRef.addValueEventListener(new ValueEventListener()
@Override
public void onDataChange(DataSnapshot dataSnapshot)
// This method is called once with the initial value and again
// whenever data at this location is updated.
if (dataSnapshot.exists())
value_clicks = dataSnapshot.child("Click").getValue(Integer.class);
Log.d(TAG, "Value is: " + value);
else
Toast.makeText(MainActivity.this, "Error!You are not on the database. Please deinstall and reinstall again", Toast.LENGTH_SHORT).show();








@Override
public void onCancelled(DatabaseError error)
// Failed to read value
Log.w(TAG, "Failed to read value.", error.toException());

);




//Item initialized
click_start = (Button) findViewById(R.id.Click_Start);
restart = (TextView) findViewById(R.id.restart);
number_final = (TextView) findViewById(R.id.Number_final);
yourscore = (TextView) findViewById(R.id.yourscore) ;
shop = (ImageView) findViewById(R.id.shop);
timert = (TextView) findViewById(R.id.time);
Highlist = (ImageView) findViewById(R.id.Highlist);

//Highscore site intent

Highlist.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View v)
Intent intent = new Intent(MainActivity.this, Highscore.class);
startActivity(intent);

);

click_start.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View v)

//clicking
number = number + value_clicks;


// setting text to points
number_final.setText(number + "");









//adding money
money_plus_value = money_plus_value + money_per_click;





Log.d(TAG, "number" + money_plus_value);



//invisibility of icons
shop.setVisibility(View.INVISIBLE);
Highlist.setVisibility(View.INVISIBLE);
money.setVisibility(View.INVISIBLE);


//calling timer and setting buttonclick true
timer();
buttonclick = true;


//restarting activity when button clicked
restart.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View v)
recreate();

);







);


//intent for shop activity
shop.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View v)
Intent intent = new Intent(MainActivity.this , shop.class);
startActivity(intent);
intent.putExtra("money" , money_2);

);

//timer method
public void timer()
if (buttonclick == false)
new CountDownTimer(30000, 1000)

public void onTick(long millisUntilFinished)
timert.setText("Seconds remaining: " + millisUntilFinished / 1000);


public void onFinish()

//clickable false

click_start.setClickable(false);


//setting money
Log.d(TAG , "valuetest" + value_money);
myRef.child("Money").setValue(value_money +money_plus_value);

money_plus_value = 0;

//setting visibility
timert.setVisibility(View.INVISIBLE);
shop.setVisibility(View.VISIBLE);
Highlist.setVisibility(View.VISIBLE);
money.setVisibility(View.VISIBLE);

//Highscore setting
// if (number > value_for_score)
// myRef_for_score.setValue(number);
//







.start();

else







return;









//task when app first time opened

public void first()


SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
if (!prefs.getBoolean("firstTime", false))
ShowPopup();

// mark first time has ran.
SharedPreferences.Editor editor = prefs.edit();
editor.putBoolean("firstTime", true);
editor.commit();





//showpopup dialog
public void ShowPopup()
final Dialog dialog= new Dialog(this);


dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.setContentView(R.layout.dialog);
dialog.show();
dialog.setCancelable(false);


final EditText edit = (EditText) dialog.findViewById(R.id.username) ;



Button bt_yes = (Button)dialog.findViewById(R.id.Button_dialog);


bt_yes.setOnClickListener(new View.OnClickListener()
@Override
public void onClick(View v)
FirebaseDatabase database1 = FirebaseDatabase.getInstance();
DatabaseReference myRef1 = database1.getReference(edit.getText().toString());

myRef1.setValue(edit.getText().toString());
myRef1.child("Click").setValue(2);
myRef1.child("Money").setValue(200);

editor = Name_saver.edit();
editor.putString("Name" , edit.getText().toString());
editor.apply();
dialog.dismiss();






);


public static String getName()
String nameer = Name_saver.getString("Name" , "ERROR");
return nameer;







1 Answer
1

The error appears on this line:

value_clicks = dataSnapshot.child("Click").getValue(Integer.class);


So it sounds like there isn't a integer value in the Click property of your JSON there.

Click

From scanning the code, you attach a listener to:

myRef = database.getReference(getName());


Which in turn is coming from:

Name_saver.getString("Name" , "ERROR");


Since Name_saver is a SharedPreferences object, it seems likely that you don't have a name saved in the shared preferences anymore.

Name_saver

SharedPreferences

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