kalkulator

package com.example.lab04;

import static java.lang.Math.abs;
import static java.lang.Math.log10;
import static java.lang.Math.pow;
import static java.lang.Math.sqrt;

import androidx.appcompat.app.AppCompatActivity;

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import org.w3c.dom.Text;

public class MainActivity extends AppCompatActivity {

    boolean isNewOperator = true;
    TextView ResultTV;
    TextView WorkingsTV;
    String operator = "";
    String workings = "";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        WorkingsTV = findViewById(R.id.workings);
        ResultTV = findViewById(R.id.result);
    }

    public void clickNumber(View view) {

        if (isNewOperator) {
            WorkingsTV.setText("");
        }
        isNewOperator = false;

        String number = WorkingsTV.getText().toString();

        switch (view.getId()) {
            case R.id.oneButton:
                number += "1";
                break;
            case R.id.twoButton:
                number += "2";
                break;
            case R.id.threeButton:
                number += "3";
                break;
            case R.id.fourButton:
                number += "4";
                break;
            case R.id.fiveButton:
                number += "5";
                break;
            case R.id.sixButton:
                number += "6";
                break;
            case R.id.sevenButton:
                number += "7";
                break;
            case R.id.eightButton:
                number += "8";
                break;
            case R.id.nineButton:
                number += "9";
                break;
            case R.id.zeroButton:
                number += "0";
                break;
            case R.id.minusButton:
                if(Double.parseDouble(number) > 0.0) {
                    number = "-" + number;
                    break;
                } else {
                    number = String.valueOf(abs(Double.parseDouble(number)));
                    break;
                }

            case R.id.commaButton:
                number += ".";
                break;
        }
        WorkingsTV.setText(number);
    }

    public void clickOperator(View view) {
        isNewOperator = true;
        workings = WorkingsTV.getText().toString();

        switch (view.getId()) {
            case R.id.sumButton:
                operator = "+";
                break;
            case R.id.subButton:
                operator = "-";
                break;
            case R.id.mulButton:
                operator = "x";
                break;
            case R.id.divButton:
                operator = "/";
                break;
            case R.id.logButton:
                operator = "log10";
                break;
            case R.id.sqrtButton:
                operator = "SQRT";
                break;
            case R.id.cuberootButton:
                operator = "^3";
                break;
            case R.id.squarerootButton:
                operator = "^2";
                break;
            case R.id.factorialButton:
                operator = "x!";
                break;

        }
        WorkingsTV.setText(operator);
    }

    public void showResult(View view) {
        String value = WorkingsTV.getText().toString();
        double result = 0.0;

        switch (operator) {
            case "+":
                result = Double.parseDouble(workings) + Double.parseDouble(value);
                break;
            case "-":
                result = Double.parseDouble(workings) - Double.parseDouble(value);
                break;
            case "x":
                result = Double.parseDouble(workings) * Double.parseDouble(value);
                break;
            case "/":
                result = Double.parseDouble(workings) / Double.parseDouble(value);
                break;
            case "SQRT":
                result = sqrt(Double.parseDouble(workings));
                break;
            case "^3":
                result = pow(Double.parseDouble(workings),3);
                break;
            case "^2":
                result = pow(Double.parseDouble(workings),2);
                break;
            case "log10":
                result = log10(Double.parseDouble(workings));
                break;
            case "x!":
                result = factorial(Double.parseDouble(workings));
                break;
        }
        ResultTV.setText(result + "");
        WorkingsTV.setText("");
        workings = "";
    }

    public double factorial(double num){
        double fact = 1;
        for(int i = 1; i <= num; i++) {
            fact *= i;
        }
        return fact;
    }


    public void allClear(View view) {
        WorkingsTV.setText("");
        ResultTV.setText("0");
        isNewOperator = true;
    }

    public void countPerc(View view) {
        double result = Double.parseDouble(WorkingsTV.getText().toString()) / 100;
        WorkingsTV.setText("%");
        ResultTV.setText(result + "");
        isNewOperator = true;
    }

}