Magic square in android

Question

I wanted to make a magic square, where I put 9 numbers, and the sum of them has to result 15 (diagonals, horizontal and vertical) I’m doing in android studio . I only have this until then:

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

import static android.icu.lang.UCharacter.GraphemeClusterBreak.V;
import static java.lang.Double.parseDouble;

public class MainActivity extends AppCompatActivity {

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



    final EditText ET1 = (EditText) findViewById(R.id.ET1);
    final EditText ET2 = (EditText) findViewById(R.id.ET2);
    final EditText ET3 = (EditText) findViewById(R.id.ET3);
    final EditText ET4 = (EditText) findViewById(R.id.ET4);
    final EditText ET5 = (EditText) findViewById(R.id.ET5);
    final EditText ET6 = (EditText) findViewById(R.id.ET6);
    final EditText ET7 = (EditText) findViewById(R.id.ET7);
    final EditText ET8 = (EditText) findViewById(R.id.ET8);
    final EditText ET9 = (EditText) findViewById(R.id.ET9);
    Button BT1 = (Button) findViewById(R.id.BT1);
    Button BT2 = (Button) findViewById(R.id.BT2);

    BT2.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {

            if (event.getAction() == MotionEvent.ACTION_DOWN) {

                ET1.setText("");
                ET2.setText("");
                ET3.setText("");
                ET4.setText("");
                ET5.setText("");
                ET6.setText("");
                ET7.setText("");
                ET8.setText("");
                ET9.setText("");
            }
            return false;
        }
    });


}
}

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 
xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.diego.teste.MainActivity">

<Button
    android:id="@+id/BT2"
    android:layout_width="118dp"
    android:layout_height="66dp"
    android:layout_marginBottom="20dp"
    android:layout_marginEnd="28dp"
    android:text="@string/limpa"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    tools:ignore="MissingConstraints"
    android:layout_marginRight="28dp" />


<Button
    android:id="@+id/BT1"
    android:layout_width="113dp"
    android:layout_height="66dp"
    android:layout_marginBottom="20dp"
    android:layout_marginStart="40dp"
    android:text="@string/verifica"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    tools:ignore="MissingConstraints"
    android:layout_marginLeft="40dp" />


<EditText
    android:id="@+id/ET1"
    android:layout_width="100dp"
    android:layout_height="70dp"
    android:layout_marginBottom="16dp"
    android:layout_marginEnd="16dp"
    android:layout_marginStart="16dp"
    android:layout_marginTop="16dp"
    android:ems="10"
    android:inputType="number"
    android:shadowColor="@android:color/background_light"
    app:layout_constraintBottom_toTopOf="@+id/ET4"
    app:layout_constraintEnd_toStartOf="@+id/ET2"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    tools:ignore="MissingConstraints" />


<EditText
    android:id="@+id/ET2"
    android:layout_width="100dp"
    android:layout_height="70dp"
    android:layout_marginBottom="16dp"
    android:layout_marginEnd="16dp"
    android:layout_marginStart="16dp"
    android:layout_marginTop="8dp"
    android:ems="10"
    android:inputType="number"
    android:shadowColor="@android:color/background_light"
    app:layout_constraintBottom_toTopOf="@+id/ET5"
    app:layout_constraintEnd_toStartOf="@+id/ET3"
    app:layout_constraintStart_toEndOf="@+id/ET1"
    app:layout_constraintTop_toTopOf="parent"
    tools:ignore="MissingConstraints" />


<EditText
    android:id="@+id/ET3"
    android:layout_width="100dp"
    android:layout_height="70dp"
    android:layout_marginBottom="16dp"
    android:layout_marginEnd="16dp"
    android:layout_marginStart="16dp"
    android:layout_marginTop="16dp"
    android:ems="10"
    android:inputType="number"
    app:layout_constraintBottom_toTopOf="@+id/ET6"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toEndOf="@+id/ET2"
    app:layout_constraintTop_toTopOf="parent"
    tools:ignore="MissingConstraints" />


<EditText
    android:id="@+id/ET4"
    android:layout_width="100dp"
    android:layout_height="70dp"
    android:layout_marginBottom="16dp"
    android:layout_marginEnd="16dp"
    android:layout_marginStart="16dp"
    android:layout_marginTop="16dp"
    android:ems="10"
    android:inputType="number"
    app:layout_constraintBottom_toTopOf="@+id/ET7"
    app:layout_constraintEnd_toStartOf="@+id/ET5"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/ET1"
    tools:ignore="MissingConstraints" />


<EditText
    android:id="@+id/ET5"
    android:layout_width="100dp"
    android:layout_height="70dp"
    android:layout_marginBottom="8dp"
    android:layout_marginEnd="8dp"
    android:layout_marginStart="8dp"
    android:layout_marginTop="8dp"
    android:ems="10"
    android:inputType="number"
    app:layout_constraintBottom_toTopOf="@+id/ET8"
    app:layout_constraintEnd_toStartOf="@+id/ET6"
    app:layout_constraintHorizontal_bias="0.526"
    app:layout_constraintStart_toEndOf="@+id/ET4"
    app:layout_constraintTop_toBottomOf="@+id/ET2"
    app:layout_constraintVertical_bias="0.529"
    tools:ignore="MissingConstraints" />


<EditText
    android:id="@+id/ET6"
    android:layout_width="100dp"
    android:layout_height="70dp"
    android:layout_marginBottom="16dp"
    android:layout_marginEnd="16dp"
    android:layout_marginStart="16dp"
    android:layout_marginTop="16dp"
    android:ems="10"
    android:inputType="number"
    app:layout_constraintBottom_toTopOf="@+id/ET9"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toEndOf="@+id/ET5"
    app:layout_constraintTop_toBottomOf="@+id/ET3"
    app:layout_constraintVertical_bias="0.428"
    tools:ignore="MissingConstraints" />


<EditText
    android:id="@+id/ET7"
    android:layout_width="100dp"
    android:layout_height="70dp"
    android:layout_marginBottom="194dp"
    android:layout_marginEnd="16dp"
    android:layout_marginStart="16dp"
    android:layout_marginTop="16dp"
    android:ems="10"
    android:inputType="number"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toStartOf="@+id/ET8"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/ET4"
    app:layout_constraintVertical_bias="1.0"
    tools:ignore="MissingConstraints" />


<EditText
    android:id="@+id/ET8"
    android:layout_width="100dp"
    android:layout_height="70dp"
    android:layout_marginBottom="190dp"
    android:layout_marginEnd="16dp"
    android:layout_marginStart="16dp"
    android:layout_marginTop="16dp"
    android:ems="10"
    android:inputType="number"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toStartOf="@+id/ET9"
    app:layout_constraintStart_toEndOf="@+id/ET7"
    app:layout_constraintTop_toBottomOf="@+id/ET5"
    tools:ignore="MissingConstraints" />

<EditText
    android:id="@+id/ET9"
    android:layout_width="100dp"
    android:layout_height="70dp"
    android:layout_marginBottom="194dp"
    android:layout_marginEnd="16dp"
    android:layout_marginStart="16dp"
    android:layout_marginTop="16dp"
    android:ems="10"
    android:inputType="number"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHorizontal_bias="0.0"
    app:layout_constraintStart_toEndOf="@+id/ET8"
    app:layout_constraintTop_toBottomOf="@+id/ET6"
    tools:ignore="MissingConstraints" />

Someone can help me , in the part of taking numbers of variables, sum and check?

Answer 1

A flexible and organized way of finding sums is by using two-dimensional arrays representing a grid. For this it will be necessary to take in each value of EdiText and interpret as whole with Integer.parseInt and place in the respective house. Then fors you can scroll through each row, column and diagonal and confirm that the total is as expected:

public boolean verificarQuadrado(int total){
    EditText ET1 = (EditText) findViewById(R.id.ET1);
    EditText ET2 = (EditText) findViewById(R.id.ET2);
    EditText ET3 = (EditText) findViewById(R.id.ET3);
    EditText ET4 = (EditText) findViewById(R.id.ET4);
    EditText ET5 = (EditText) findViewById(R.id.ET5);
    EditText ET6 = (EditText) findViewById(R.id.ET6);
    EditText ET7 = (EditText) findViewById(R.id.ET7);
    EditText ET8 = (EditText) findViewById(R.id.ET8);
    EditText ET9 = (EditText) findViewById(R.id.ET9);

    int[][] numeros = {
        { 
            Integer.parseInt(ET1.getText().toString()),
            Integer.parseInt(ET2.getText().toString()),
            Integer.parseInt(ET3.getText().toString())
        },
        { 
            Integer.parseInt(ET4.getText().toString()),
            Integer.parseInt(ET5.getText().toString()),
            Integer.parseInt(ET6.getText().toString())
        },
        { 
            Integer.parseInt(ET7.getText().toString()),
            Integer.parseInt(ET8.getText().toString()),
            Integer.parseInt(ET9.getText().toString())
        }   
    };

    for (int  i = 0; i < numeros.length; ++i){
        int linha = 0, coluna = 0;

        for (int j = 0; j < numeros[i].length; ++j){
            linha += numeros[i][j];
            coluna += numeros[j][i];
        }

        if (linha != total || coluna != total)
            return false;
    }

    int diag1 = 0, diag2 = 0;

    for (int i = 0; i < numeros.length; ++i){
        diag1 += numeros[i][i];
        diag2 += numeros[i][numeros.length-i-1];
    }

    return diag1 == total && diag2 == total;
}

This method verificarQuadrado return true whether the magic square has the desired total or false otherwise. So you just have to use it like this:

if (verificarQuadrado(15)) { //ou if(verificarQuadrado(15) == true)
    //código para quando o usuário ganhou
}

Note that I assumed that the EditText are positioned as follows:

-------------------
| ET1 | ET2 | ET3 |
-------------------
| ET4 | ET5 | ET6 |
-------------------
| ET7 | ET8 | ET9 |
-------------------

In addition the verification algorithm does not use any fixed size and so will work for a magic 3x3, 4x4 or larger square, provided it starts the two-dimensional array appropriately.

---

Note: From API 26 you don’t need the conversion when you do the findViewById, and so when you fetch an element from the layout:

EditText ET1 = (EditText) findViewById(R.id.ET1);

You can start doing it like:

EditText ET1 = findViewById(R.id.ET1);

Which is simpler and less boring to write.