Tag: applications

I just started learning Android app development. As a beginner project, I build a simple calculator app, but every time I execute it, all the other functions besides the addition function will give false results.
Here is the Java code I wrote. (MainActivity.java)

package com.example.calc;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {
    TextView result; 
    EditText number1, number2;  
    Button add;
    Button sub;
    Button mul;
    Button div;

    public float result_num = 0;
    public int num1;
    public int num2;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        result = (TextView) findViewById(R.id.result);

        number1 = (EditText) findViewById(R.id.number1);
        number2 = (EditText) findViewById(R.id.number2);
        //numbers
        add = (Button) findViewById(R.id.add);
        sub = (Button) findViewById(R.id.sub);
        mul = (Button) findViewById(R.id.mul);
        div = (Button) findViewById(R.id.div);

        ///////////Calculation part///////////

        add.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                num1 = Integer.parseInt(number1.getText().toString());
                num2 = Integer.parseInt(number2.getText().toString());
                result_num = (num1 + num2);
                result.setText(String.valueOf(result_num));

            }
        });
        sub.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                num1 = Integer.parseInt(number1.getText().toString());
                num2 = Integer.parseInt(number1.getText().toString());
                result_num = (num1 - num2);
                result.setText(String.valueOf(result_num));
            }
        });
        mul.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                num1 = Integer.parseInt(number1.getText().toString());
                num2 = Integer.parseInt(number1.getText().toString());
                result_num = (num1 * num2);
                result.setText(String.valueOf(result_num));
            }
        });
        div.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                num1 = Integer.parseInt(number1.getText().toString());
                num2 = Integer.parseInt(number1.getText().toString());
                result_num = (num1 / num2);
                result.setText(String.valueOf(result_num));
            }
        });
    }
}

The XML code for the app. (Activity_main.xml)

I use a linear layout

Please help me.
Thanks.