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);

package com.iven.test;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

private static final String TAG = "MainActivity";

@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);

}

private void display(int solution) {
    Log.d(TAG,"Output :" +solution);


}

}

Done.
05-25 11:59:24.146 10779-10779/com.iven.test D/MainActivity: Output :33

the code must be

int actualHours = weekday*5 + weekend * 2;
int solution = optimalHours - actualHours;
display(solution);

<TextView
    android:id="@+id/display_text_view"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textSize="45sp" />

package com.example.android.practiceset2; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.widget.TextView;

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);
}

}

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;

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);
// PASTE CODE YOU WANT TO TEST HERE

}

/**

• 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);}
}

And that's what my "activity_main.xml" looks like:

worked

Works

package example.com.android.practiseset2;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;

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

}

goooooood work

can someone plz write the full correct xml code for this quiz

Dear Guys (and girls :))
In this course, they mentions "instructor Notes", Where can I find them?

@KobiPeeri, you can find them below the video (circled by red color in the screenshot)...

This code works only in the cellphone. Running in your cell. In the preview it isn't appear.

Não vai funcionar no preview. Rode no celular que irá funcionar,

import android.widget.TextView;
if any one like me encountered a problem with textview
add the line above
import android.widget.TextView;

Привет,

Я поместил весь код, кроме последней строки, то есть display(solution);вне onCreate()метода

public class MainActivity extends AppCompatActivity {

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

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

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    // PASTE CODE YOU WANT TO TEST HERE

    display(solution);

}

...
...
}

Не так ли?
Я получаю сообщение об ошибке: ошибка: ожидается
и когда я помещаю курсор в строку actualHoursили weekendиз строки. actualHours = actualHours + weekend * 2;Он говорит: Неизвестный класс: «actualHours» и «Неизвестный класс:« выходные »

Заранее спасибо!!!

start learning again

Done!

package com.example.android.practiceset2;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    @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);

    }

    /**
     * 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(String text) {
        TextView t = (TextView) findViewById(R.id.display_text_view);
        t.setText(text);
    }

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

    public void display1(String text) {
        display(text);
    }

    public void display2(String text) {
        TextView t = (TextView) findViewById(R.id.display_text_view_2);
        t.setText(text);
    }

    public void display3(String text) {
        TextView t = (TextView) findViewById(R.id.display_text_view_3);
        t.setText(text);
    }
}

i wrote them manually and lol i didnt place a dot between t and setText now that i rewrote that part is all good t.setText
(i need to be more carefull with the punctuations and parantheses) works perfect :)

Getting the following code when I try to copy and paste the MainActivity.java code

error: package android.support.v7.app does not exist

package com.example.android.practiceset2;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

@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);

}

/**
 * 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(String text) {
    TextView t = (TextView) findViewById(R.id.display_text_view);
    t.setText(text);
}

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

public void display1(String text) {
    display(text);
}

public void display2(String text) {
    TextView t = (TextView) findViewById(R.id.display_text_view_2);
    t.setText(text);
}

public void display3(String text) {
    TextView t = (TextView) findViewById(R.id.display_text_view_3);
    t.setText(text);
}

}

Getting the following code when I try to copy and paste the MainActivity.java code

error: package android.support.v7.app does not exist

Hi @al130m

You have the same errors like everybody else from the moment when you create a new project and copy paste everything :)

Delete this import line from your code:

import android.support.v7.app.AppCompatActivity;

Then Select "AppCombatActivity" from your MainActivity class:

public class MainActivity extends AppCompatActivity

Press ALT + ENTER. -. new small window shows up ->. select "import class".

That's it.
Basically, you will change the import code to the recent package.

package com.example.android.practiceset2;
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);
    // 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);

}

/**
 * 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(String text) {
    TextView t = (TextView) findViewById(R.id.display_text_view);
    t.setText(text);
}

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

}

this works for me
package com.example.android.practiceset2;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;

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 opimalHours = 7 * 8;

    int actualHours = (weekday * 5) + (weekend * 2);
    int solution = opimalHours - actualHours;
    display(solution);
}

public void display(int n) {
    TextView textView = (TextView) findViewById(R.id.display_text_view);
    textView.setText(Integer.toString(n));
}

}

and in ActivityMain XML

<TextView
    android:id="@+id/display_text_view"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text=""
    android:textSize="45sp" />

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 * 5 + 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);
}

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);
}

}