Introduction

In this tutorial, we will introduce the fundamental aspects of native app development for Android and iOS. You will learn about the languages used, the development tools, and the platform-specific design principles. By the end of this tutorial, you should have a basic understanding of how to build native apps for these two platforms.

Prerequisites:
- Basic understanding of programming concepts
- Familiarity with any one programming language would be beneficial but not necessary

Step-by-Step Guide

1. Android Development

Android apps are primarily built using Java or Kotlin, with Kotlin being the more modern choice.

Development Tools

The most common tool for Android development is Android Studio, provided by Google. It includes a code editor, emulator, debugging tools, and more.

Design Principles

Android follows Material Design principles, featuring bold, graphic design and intentional white space.

2. iOS Development

iOS apps are written in Swift or Objective-C, with Swift being the more contemporary and widely-used language.

Development Tools

For iOS development, Apple provides Xcode, an integrated development environment (IDE). It's a comprehensive toolset for developing apps.

Design Principles

iOS apps follow Human Interface Guidelines laid out by Apple, featuring a focus on simplicity and a great user experience.

Code Examples

1. Android "Hello, World!" in Kotlin

import android.app.Activity
import android.os.Bundle
import android.widget.TextView

// This is the main Activity (the entry point for your app)
class MainActivity : Activity() {

    // OnCreate is where you initialize your activity
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        // Create a TextView and set its text to "Hello, world!"
        val tv = TextView(this)
        tv.text = "Hello, World!"
        setContentView(tv)
    }
}

This simple Android app displays "Hello, World!" on the screen. The MainActivity is the entry point of the app and onCreate is where we initialize our activity.

2. iOS "Hello, World!" in Swift

import UIKit

// This is the main view controller (the entry point for your app)
class ViewController: UIViewController {

    // viewDidLoad is where you set up your view after it's been loaded
    override func viewDidLoad() {
        super.viewDidLoad()

        // Create a UILabel and set its text to "Hello, world!"
        let label = UILabel()
        label.frame = CGRect(x: 0, y: 0, width: 200, height: 21)
        label.center = self.view.center
        label.textAlignment = .center
        label.text = "Hello, World!"
        self.view.addSubview(label)
    }
}

This simple iOS app displays "Hello, World!" in the center of the screen. The ViewController is the entry point of the app and viewDidLoad is where we set up our view after it's been loaded.

Summary

We've covered the basics of native Android and iOS development, including the languages used (Kotlin and Swift), the main development tools (Android Studio and Xcode), and the design principles for each platform.

For further learning, you may want to explore more advanced topics, such as handling user interaction, networking, and storing data locally on the device.

Practice Exercises

1. Create a basic Android app that displays your name on the screen.
2. Create a basic iOS app that displays your name in the center of the screen.
3. Modify the above apps to change the text color and background color.

Remember, practice is key to mastering any new programming language or platform. Keep experimenting and building!