CH 6 iOS

Here is my UIViewController class:

//

//  ViewController.swift

//  CH6Ex1Circle

//

//  Created by stu2017 on 10/24/17.

//  Copyright © 2017 stu2017. All rights reserved.

//

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var tbRad: UITextField!

    @IBOutlet weak var lblCirc: UILabel!

    @IBOutlet weak var lblArea: UILabel!

    override func viewDidLoad() {

        super.viewDidLoad()

        // Do any additional setup after loading the view, typically from a nib.

    }

    override func didReceiveMemoryWarning() {

        super.didReceiveMemoryWarning()

        // Dispose of any resources that can be recreated.

    }

    @IBAction func btnCalc(_ sender: UIButton) {

        let rad=Double(tbRad.text!);

        let circ1=Circle(radius:rad!);

        let a=String(format: "%.2f", circ1.getArea());

        let c=String(format: "%.2f", circ1.getCircumference());

        lblArea.text="Area: \(a)";

        lblCirc.text="Circumfrence: \(c)";

    }

}

 Here is my circle class

//

//  Circle.swift

//  CH6Ex1Circle

//

//  Created by stu2017 on 10/24/17.

//  Copyright © 2017 stu2017. All rights reserved.

//

import Foundation

class Circle {

    var radius = 0.0

    

    init(radius: Double) { // Constructor

        self.radius = radius

        

    }

    var Area: Double{

        return 3.14*(radius*radius)

    }

    

    func getArea() -> Double {

        return 3.14*(radius*radius)

    }

    

    var Circumference: Double {

        return 2*3.14*radius

    }

    func getCircumference() -> Double{

        return 2*3.14*radius

    }

}

Week 4 AppInventor

Hello World

SMS/Location

Circle App

Unit 5 Chapter 3Android Intro Hello World Button

package com.example.hellobuttonweek5;//this line is unique to your app
import androidx.appcompat.app.AppCompatActivity;

import android.content.res.Resources;
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 {

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

    }

    private void initButton() {
        Resources res= getResources();
        Button button = (Button) findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                EditText firstName = (EditText) findViewById(R.id.editTextTextPersonName);
                TextView textView = (TextView) findViewById(R.id.textView);
                String displayString=res.getString(R.string.hello,firstName.getText().toString());
                textView.setText(displayString);
            }
        });
    }

    private void initButtonClear() {
        Button clear = (Button) findViewById(R.id.button2);
        clear.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                EditText firstName = (EditText) findViewById(R.id.editTextTextPersonName);
                TextView textView = (TextView) findViewById(R.id.textView);
                textView.setText("Hello World!");
                firstName.setText("");
            }
        });

    }
}

Update 9/20/2021:

If you are on the latest version of Android Studio (Android Studio Arctic Fox Version 2020.3.1) and you are on JAVA version 11 or early you may get the following error when executing your (Newly created) Android application:

> Failed to apply plugin 'com.android.internal.application'.
   > Android Gradle plugin requires Java 11 to run. You are currently using Java 1.8.
     You can try some of the following options:
       - changing the IDE settings.
       - changing the JAVA_HOME environment variable.
       - changing `org.gradle.java.home` in `gradle.properties`.

SOLUTION:Make sure you load Java11 or later (I have version 15) -

Open the Project get to Files->Settings->Build,Execution,Deployment->Build Tools->Gradle-> Use the drop down for Gradle JDK on that page and select a Java version 11 or later (Which you may have just loaded). I picked JDK 15.