Mobile App Development 2021W Lecture 16

Video

Video from the lecture given on March 15, 2021 is now available.

Code

TapDemo (iOS) ContentView.swift

//
//  ContentView.swift
//  Shared
//
//  Created by Anil Somayaji on 2021-03-15.
//

import SwiftUI

struct ContentView: View {
    @State var count = 0
    var body: some View {
        VStack{
            Button("Tap here!", action: onTapped)
                .font(/*@START_MENU_TOKEN@*/.title/*@END_MENU_TOKEN@*/)
            
            Text("You have tapped \(count) times.")
            .padding()
        }
    }
    func onTapped() {
        count = count + 1
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

TapDemo (Android) MainActivity.kt

package carleton.comp1601.tapdemo

import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import android.view.View
import android.widget.TextView

class MainActivity : AppCompatActivity() {
    private lateinit var myMessage: TextView
    private var count = 0

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        Log.d("Tap Demo", "Created")

        myMessage = findViewById(R.id.myMessage)
    }

    override fun onResume() {
        super.onResume()
        Log.d("Tap Demo", "Resumed")
    }

    override fun onPause() {
        super.onPause()
        Log.d("Tap Demo", "Paused")
    }

    override fun onStart() {
        super.onStart()
        Log.d("Tap Demo", "Started")
    }

    override fun onStop() {
        super.onStop()
        Log.d("Tap Demo", "Stopped")
    }

    override fun onDestroy() {
        super.onDestroy()
        Log.d("Tap Demo", "Destroyed")
    }

    override fun onRestart() {
        super.onRestart()
        Log.d("Tap Demo", "Restarted")
    }

    fun myButtonPressed(v: View) {
        count++
        myMessage.text = "You clicked $count times."
    }
}

TapDemo (Android) activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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:id="@+id/TapDemo"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/myButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="myButtonPressed"
        android:text="Tap me!"
        android:textAppearance="@style/TextAppearance.AppCompat.Display1"
        app:layout_constraintBottom_toTopOf="@+id/myMessage"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/myMessage"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="You haven't tapped yet."
        android:textAppearance="@style/TextAppearance.AppCompat.Display1"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>