Q:

NullPointerException when trying to print random values in android studio

I keep getting a null pointer exception at lines 99 and 77, which is where I attempt to print the random values created by the random class (line 99), and where I call my setQuestion method (line 77. randomNum to the layout_game xml file. I'm not sure why I am getting a null value because when i log the values to the console it says that values are being generated. 
package com.grantsolutions.mathgamechapter1;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import java.util.Random;

public class GameActivity extends Activity implements OnClickListener {
int correctAnswer;
Button buttonObjectChoice1;
Button buttonObjectChoice2;
Button buttonObjectChoice3;
TextView textObjectPartA //it says that textObjectPartA and B are never used;
TextView textObjectPartB;
TextView textObjectScore;
TextView textObjectLevel;
int currentScore;
int currentLevel = 1;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.layout_game);

    //declaring variables for game

    //no longer being declared

    /*int partA = 2;
    int partB = 2;
    correctAnswer = partA * partB;
    int wrongAnswer1 = correctAnswer - 1;
    int wrongAnswer2 = correctAnswer + 1;
    /*this is where we link the variables
    from  the java code to the button UI in
     activity_game xml itself
     */
    TextView textObjectPartA = (TextView) findViewById(R.id.holdTextA);

    TextView textObjectPartB = (TextView) findViewById(R.id.holdTextB);
    textObjectScore = (TextView) findViewById(R.id.textLevel);
    textObjectLevel = (TextView) findViewById(R.id.textScore);

    buttonObjectChoice1 =
            (Button) findViewById(R.id.choice1);

    buttonObjectChoice2 =
            (Button) findViewById(R.id.choice2);

    buttonObjectChoice3 =
            (Button) findViewById(R.id.choice3);
    /*Use the setText method of the class on our objects
    to show our variable values on the UI elements.
    Similar to outputting to the console in the exercise,
    only using the setText method*/

    //telling the console to listen for button clicks from the user
    buttonObjectChoice1.setOnClickListener(this);
    buttonObjectChoice2.setOnClickListener(this);
    buttonObjectChoice3.setOnClickListener(this);
    setQuestion();

}

void setQuestion() {
    Random randomNum;
    randomNum = new Random();

    int partA = 0;
    int numberRange = currentLevel * 3;
    partA = randomNum.nextInt(numberRange) + 1;
     //removes possibility of a zero value
    int partB = randomNum.nextInt(numberRange) + 1;

    correctAnswer = partA * partB;
    Log.i("info", ""+partA);
    Log.i("info", ""+partB);
    Log.d("info", ""+partA);
    int wrongAnswer1 = correctAnswer - 2;
    int wrongAnswer2 = correctAnswer + 2;
    Log.i("info", ""+partA);
    Log.i("info", ""+partB);
    textObjectPartA.setText(""+partA); //error here
    textObjectPartB.setText(""+partB);
    //case for setting multiple choice buttons
    int buttonLayout = randomNum.nextInt(3);
    switch (buttonLayout) {
        case 0:
            buttonObjectChoice1.setText("" + correctAnswer);
            buttonObjectChoice2.setText("" + wrongAnswer1);
            buttonObjectChoice3.setText("" + wrongAnswer2);
            break;
        case 1:
            buttonObjectChoice2.setText("" + correctAnswer);
            buttonObjectChoice1.setText("" + wrongAnswer1);
            buttonObjectChoice3.setText("" + wrongAnswer2);
            break;
        case 2:
            buttonObjectChoice3.setText("" + correctAnswer);
            buttonObjectChoice1.setText("" + wrongAnswer1);
            buttonObjectChoice2.setText("" + wrongAnswer2);
            break;
    }

}

void updateScoreAndLevel(int answerGiven) {
    if (isCorrect(answerGiven)) {
        for (int i = 1; i <= currentLevel; i++) {
            currentScore = currentScore + i;

        }
    } else {
        currentLevel = 1;
        currentScore = 0;

    }

    currentLevel++;

}

boolean isCorrect(int answerGiven) {
    boolean correctTrueOrFalse = true;
    if (answerGiven == correctAnswer) {//YAY!
        Toast.makeText(getApplicationContext(), "Well Done", Toast.LENGTH_LONG).show();

    }
    else {//If wrong print this instead
        Toast.makeText(getApplicationContext(), "You're wrong", Toast.LENGTH_SHORT).show();
    }  //case for each button being made
    correctTrueOrFalse = false;

    return correctTrueOrFalse;
}

    @Override
    public void onClick (View view){
        //declaring a new int to use in all cases
        int answerGiven;

        switch (view.getId()) {
            //case for each button being made

            case R.id.choice1:
                //button1 information goes here
                //initialize a new integer with the value
                //contained in buttonObjectChoice1
                answerGiven = Integer.parseInt("" +       buttonObjectChoice1.getText());
                //check if the right answer

                break;

            case R.id.choice2:
                //button2 information goes here
                answerGiven = Integer.parseInt("" + buttonObjectChoice2.getText());

                break;

            case R.id.choice3:
                //button 3 information goes here
                answerGiven = Integer.parseInt("" + buttonObjectChoice3.getText());
                break;

        }

    }

}

code snippet for lines 99 and 77 here
line 77
  @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.layout_game);

    TextView textObjectPartA = (TextView) findViewById(R.id.holdTextA);

    TextView textObjectPartB = (TextView) findViewById(R.id.holdTextB);
    textObjectScore = (TextView) findViewById(R.id.textLevel);
    textObjectLevel = (TextView) findViewById(R.id.textScore);

    buttonObjectChoice1 =
            (Button) findViewById(R.id.choice1);

    buttonObjectChoice2 =
            (Button) findViewById(R.id.choice2);

    buttonObjectChoice3 =
            (Button) findViewById(R.id.choice3);
    /*Use the setText method of the class on our objects
    to show our variable values on the UI elements.
    Similar to outputting to the console in the exercise,
    only using the setText method*/

    //telling the console to listen for button clicks from the user
    buttonObjectChoice1.setOnClickListener(this);
    buttonObjectChoice2.setOnClickListener(this);
    buttonObjectChoice3.setOnClickListener(this);
    setQuestion(); //code error shown in this line

}

line 99
   Log.i("info", ""+partA);
    Log.i("info", ""+partB); 
    textObjectPartA.setText(""+partA); //error here
    textObjectPartB.setText(""+partB);

the layout_game file
<?xml version="1.0" encoding="utf-8"?>

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:text="2"
    android:id="@+id/holdTextA"
    android:layout_marginTop="44dp"
    android:textSize="50sp"
    android:layout_alignParentTop="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_marginLeft="44dp"
    android:layout_marginStart="44dp" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:text="X"
    android:id="@+id/textView4"
    android:layout_alignTop="@+id/holdTextA"
    android:layout_centerHorizontal="true"
    android:textSize="50sp" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:text="4"
    android:id="@+id/holdTextB"
    android:textSize="50sp"
    android:layout_above="@+id/textView6"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true"
    android:layout_marginRight="53dp"
    android:layout_marginEnd="53dp" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:text="="
    android:id="@+id/textView6"
    android:layout_marginTop="118dp"
    android:layout_below="@+id/textView4"
    android:layout_alignLeft="@+id/textView4"
    android:layout_alignStart="@+id/textView4"
    android:textSize="60sp" />

<Button
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/choice1"
    android:text="2"
    android:textSize="40sp"
    android:layout_alignParentBottom="true"
    android:layout_alignRight="@+id/holdTextA"
    android:layout_alignEnd="@+id/holdTextA"
    android:layout_marginBottom="37dp" />

<Button
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="4"
    android:id="@+id/choice2"
    android:layout_alignBottom="@+id/choice1"
    android:layout_alignLeft="@+id/holdTextB"
    android:layout_alignStart="@+id/holdTextB"
    android:textSize="40sp" />

<Button
    style="?android:attr/buttonStyleSmall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="3"
    android:id="@+id/choice3"
    android:layout_alignBottom="@+id/choice1"
    android:layout_centerHorizontal="true"
    android:layout_alignTop="@+id/choice1"
    android:textSize="40sp" />

A:

In your 
onCreateView()

you have declared 
TextView textObjectPartA = (TextView) findViewById(R.id.holdTextA);

This way your global variable textObjectPartA has not been set, and hence the null point exception.

