Android Development for Beginners : Practice Set 2 Sleep Debt Example

MainActivity.java

        int weekday = 5;
        int weekend = 9;
        int optimalHours = 7 * 8;

        int actualHours = weekday;
        actualHours = actualHours + weekend * 2;
        int solution = optimalHours - actualHours;
        display(solution);

My compiler fail to run successfully. There's this error:
error: method display(int) is already defined in class MainActivity
public void display(int i) {

My compiler fail to run successfully. There's this error:
error: method display(int) is already defined in class MainActivity
public void display(int i) {

Anyone can help me on this please?

@yyssimon
I think you have a display method in the MainActivity onCreate{}.
Try putting it outside {} of onCreate.

Example:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    // PASTE CODE YOU WANT TO TEST HERE
    int weekday = 5;
    int weekend = 9;
    int optimalHours = 7 * 8;

    int actualHours = weekday;
    actualHours = actualHours + weekend * 2;
    int solution = optimalHours - actualHours;
    display(solution);
}
public void display(int i) {
    TextView t = (TextView) findViewById(R.id.display_text_view);
    t.setText("" + i);
}

M final output

Please help
33 is not showing me in the app after writing proper code as well

This is the white screen but no 33

In case its 2021 with updated android studio.. and the old code has some buggs..
try this one it worked for me.

package com.example.android.practiceset2;

import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    int weekday = 5;
    int weekend = 9;
    int optimalHours = 7 * 8;

    int actualHours = weekday;
    actualHours = actualHours + weekend * 2;
    int solution = optimalHours - actualHours;
    display(solution);
}

/**
 * Display methods that allow the text to appear on the screen. Don't worry if you don't know
 * how these work yet. We'll be covering them in lesson 3.
 */

public void display (int i) {
    TextView t = (TextView) findViewById(R.id.display_text_view);
    t.setText(""+i);
}

}