Android Java Calculator (Clear Button)

Question

So I am working with a simple android calculator, I have made 5 buttons, +, -, /, * and C. C is supposed to reset all the text field so that they get erased. Basically turned null. Here is the java code, but I do not know how to write the code for the null button. Erasing the content that is inside them the text fields (editTextNumber1, editTextNumber2 and editTextnumber3) These are textboxes, 1 and 2 is where you input the three numbers, 3 is the textbox outputting the answer after the calculation have been made of the numbers that originally was putted in textboxes 1 and 2. like you do on a real calculator when you tap C (Clear button).

package com.example.raknaretest;

import androidx.appcompat.app.AppCompatActivity;

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

public class MainActivity extends AppCompatActivity {

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

    public void AddBtn(View v){
    EditText et1 =(EditText)findViewById(R.id.editTextNumber1);
    EditText et2 =(EditText)findViewById(R.id.editTextNumber2);
    EditText et3 =(EditText)findViewById(R.id.editTextNumber3);

    int n1 = Integer.parseInt(et1.getText().toString());
    int n2 = Integer.parseInt(et2.getText().toString());
    int result = n1+n2;

    et3.setText("= " + result);
}

public void SubBtn(View v){
    EditText et1 =(EditText)findViewById(R.id.editTextNumber1);
    EditText et2 =(EditText)findViewById(R.id.editTextNumber2);
    EditText et3 =(EditText)findViewById(R.id.editTextNumber3);

    int n1 = Integer.parseInt(et1.getText().toString());
    int n2 = Integer.parseInt(et2.getText().toString());
    int result = n1 - n2;

    et3.setText("= " + result);

}
public void MultBtn(View v){
    EditText et1 =(EditText)findViewById(R.id.editTextNumber1);
    EditText et2 =(EditText)findViewById(R.id.editTextNumber2);
    EditText et3 =(EditText)findViewById(R.id.editTextNumber3);

    int n1 = Integer.parseInt(et1.getText().toString());
    int n2 = Integer.parseInt(et2.getText().toString());
    int result = n1 * n2;

    et3.setText("= " + result);
}
public void DivBtn(View v){
    EditText et1 =(EditText)findViewById(R.id.editTextNumber1);
    EditText et2 =(EditText)findViewById(R.id.editTextNumber2);
    EditText et3 =(EditText)findViewById(R.id.editTextNumber3);

    int n1 = Integer.parseInt(et1.getText().toString());
    int n2 = Integer.parseInt(et2.getText().toString());
    int result = n1 / n2;

    et3.setText("= " + result);
}

   // public void ClearBtn(View view) {

   // }
}

Answer 1

See other answers on how to clear the text.

I suggest you save your EditTexts in local variables and create methods for fetching their values. Also, method names should start with a lower case character and be private (since you probably don't want to use them outside of MainActivity) and variable names should be significant:

package com.example.raknaretest;

import androidx.appcompat.app.AppCompatActivity;

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

public class MainActivity extends AppCompatActivity {
    private EditText et1, et2, et3;

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

        et1 = (EditText) findViewById(R.id.editTextNumber1);
        et2 = (EditText) findViewById(R.id.editTextNumber2);
        et3 = (EditText) findViewById(R.id.editTextNumber3);
    }

    private void addBtn(View v) {
        int result = value(et1) + value(et2);
        displayResult(result);
    }

    private void subBtn(View v) {
        int result = value(et1) - value(et2);
        displayResult(result);
    }

    private void multBtn(View v) {
        int result = value(et1) * value(et2);
        displayResult(result);
    }

    private void divBtn(View v) {
        int result = value(et1) / value(et2);
        displayResult(result);
    }

    private int value(EditText editText) {
        return Integer.parseInt(editText.getText().toString());
    }

    private void displayResult(int result) {
        et1.getText().clear();
        et2.getText().clear();
        et3.setText("= " + result);
    }
}

Answer 2

To clear the text fields use

et.getText().clear();

or

et.setText("")