Why is the app crashing??

Question

Android

package com.example.roman.geoguiz;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.widget.Button;
import android.view.View;

import android.widget.TextView;
import android.widget.Toast;

public class GuizActivity extends AppCompatActivity {

    private Button mTrueButton;
    private Button mFalseButton;
    private Button mNextButton;
    private TextView mTV;
    private int mCurrentIndex = 0;

    TrueFalse[] mQuesitonBank = new TrueFalse[]{
            new TrueFalse(R.string.onn, true),
            new TrueFalse(R.string.inn, true),
            new TrueFalse(R.string.gcc, true),
    };

    private void updeteQueation(){
        int question = mQuesitonBank[mCurrentIndex].getQuestion();
        mTV.setText(question);
    }

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

        mTV = (TextView) findViewById(R.id.TV);
        mTrueButton = (Button) findViewById(R.id.button_true);
        mFalseButton = (Button) findViewById(R.id.button_false);
        mNextButton = (Button) findViewById(R.id.button_next);

        mTrueButton.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view){
                Toast.makeText(GuizActivity.this, R.string.correct_toast, Toast.LENGTH_SHORT).show();
            }
        });

        mFalseButton.setOnClickListener(new View.OnClickListener(){
            public void onClick(View view){
                Toast.makeText( GuizActivity.this, R.string.incorrect_toast, Toast.LENGTH_SHORT).show();
            }
        });

        mNextButton.setOnClickListener(new View.OnClickListener(){
            public void onClick(View v){
                mCurrentIndex = (mCurrentIndex++) % mQuesitonBank.length;
                updeteQueation();
            }

        });

        updeteQueation();

    }
    protected boolean onCreateOptionMeny(Menu menu){

        return true;
    }
}

package com.example.roman.geoguiz;

public class TrueFalse extends Object {
    private int mQuestion;

    private boolean mTrueQuestion;

    public TrueFalse (int question, boolean trueQuestion){
        mQuestion = question;
        mTrueQuestion = trueQuestion;
    }

    public boolean isTrueQuestion() {
        return mTrueQuestion;
    }

    public void setTrueQuestion(boolean trueQuestion) {
        mTrueQuestion = trueQuestion;
    }

    public int getQuestion() {
        return mQuestion;
    }

    public void setQuestion(int question) {
        mQuestion = question;
    }
}

The compiler does not give any errors, but the application crashes. Where is the error possible?
PS Testing on real device with API 23

Answer 1

java.lang.RuntimeException: Unable to start activity widget.TextView

Here is your error. Most likely here:
mTV = (TextView) findViewById(R.id.TV);
R.id.TV not TextView

Answer 2

You are right, there is a mistake in these lines!! But now I can't figure out why there is an error? The thing is that R.id.TV is a TextView