Free Swift 2 How To Make An App For Mac
. print( 'Hello, world!' ). // Prints 'Hello, world!'
If you have written code in C or Objective-C, this syntax looks familiar to you—in Swift, this line of code is a complete program. You don’t need to import a separate library for functionality like input/output or string handling. Code written at global scope is used as the entry point for the program, so you don’t need a main function. You also don’t need to write semicolons at the end of every statement.
This tour gives you enough information to start writing code in Swift by showing you how to accomplish a variety of programming tasks. Don’t worry if you don’t understand something—everything introduced in this tour is explained in detail in the rest of this book. var myVariable = 42. myVariable = 50. let myConstant = 42 A constant or variable must have the same type as the value you want to assign to it. However, you don’t always have to write the type explicitly.
Providing a value when you create a constant or variable lets the compiler infer its type. In the example above, the compiler infers that myVariable is an integer because its initial value is an integer. If the initial value doesn’t provide enough information (or if there is no initial value), specify the type by writing it after the variable, separated by a colon. Experiment Change optionalName to nil.
What greeting do you get? Add an else clause that sets a different greeting if optionalName is nil. If the optional value is nil, the conditional is false and the code in braces is skipped. Otherwise, the optional value is unwrapped and assigned to the constant after let, which makes the unwrapped value available inside the block of code.
Another way to handle optional values is to provide a default value using the?? If the optional value is missing, the default value is used instead. Experiment Try removing the default case.
Free Swift 2 How To Make An App For Mac
What error do you get? Notice how let can be used in a pattern to assign the value that matched the pattern to a constant. After executing the code inside the switch case that matched, the program exits from the switch statement.
Free Swift 2 How To Make An App For Mac Pro
Execution doesn’t continue to the next case, so there is no need to explicitly break out of the switch at the end of each case’s code. You use for- in to iterate over items in a dictionary by providing a pair of names to use for each key-value pair. Dictionaries are an unordered collection, so their keys and values are iterated over in an arbitrary order. Experiment Write a function that compares two Rank values by comparing their raw values. By default, Swift assigns the raw values starting at zero and incrementing by one each time, but you can change this behavior by explicitly specifying values. In the example above, Ace is explicitly given a raw value of 1, and the rest of the raw values are assigned in order.
You can also use strings or floating-point numbers as the raw type of an enumeration. Use the rawValue property to access the raw value of an enumeration case. Use the init?(rawValue:) initializer to make an instance of an enumeration from a raw value. It returns either the enumeration case matching the raw value or nil if there is no matching Rank.
Experiment Add a color method to Suit that returns “black” for spades and clubs, and returns “red” for hearts and diamonds. Notice the two ways that the hearts case of the enumeration is referred to above: When assigning a value to the hearts constant, the enumeration case Suit.hearts is referred to by its full name because the constant doesn’t have an explicit type specified. Inside the switch, the enumeration case is referred to by the abbreviated form.hearts because the value of self is already known to be a suit. You can use the abbreviated form anytime the value’s type is already known.
If an enumeration has raw values, those values are determined as part of the declaration, which means every instance of a particular enumeration case always has the same raw value. Another choice for enumeration cases is to have values associated with the case—these values are determined when you make the instance, and they can be different for each instance of an enumeration case. You can think of the associated values as behaving like stored properties of the enumeration case instance.
For example, consider the case of requesting the sunrise and sunset times from a server. The server either responds with the requested information, or it responds with a description of what went wrong. Experiment Add a third case to ServerResponse and to the switch. Notice how the sunrise and sunset times are extracted from the ServerResponse value as part of matching the value against the switch cases. Use struct to create a structure. Structures support many of the same behaviors as classes, including methods and initializers.
One of the most important differences between structures and classes is that structures are always copied when they are passed around in your code, but classes are passed by reference. Experiment Add another requirement to ExampleProtocol. What changes do you need to make to SimpleClass and SimpleStructure so that they still conform to the protocol?
Notice the use of the mutating keyword in the declaration of SimpleStructure to mark a method that modifies the structure. The declaration of SimpleClass doesn’t need any of its methods marked as mutating because methods on a class can always modify the class. Use extension to add functionality to an existing type, such as new methods and computed properties. You can use an extension to add protocol conformance to a type that is declared elsewhere, or even to a type that you imported from a library or framework.
Project 18: Bindings Practice your skill with Cocoa bindings by building a Fahrenheit to Celsius temperature converter, all powered by key-value coding and key-value observing. While building projects, you'll learn all this and more:. How Cocoa on macOS differs from Cocoa Touch on iOS. (Note: if you're not interested in iOS, don't worry – you don't need any iOS experience to follow along, and the iOS parts are kept to a minimum!). Creating advanced user interfaces with NSTableView, NSCollectionView, NSStackView, NSSplitView, and the all-new NSGridView.
How to build apps that look great in multi-window and tabbed user environments. Designing your apps with powerful native components such as NSButton, NSTextView, NSSegmentedControl, NSImageView, and more. Working with the filesystem, and using system services such as sharing and drag and drop.
Customizing your app's user interface so it looks great in both light and dark mode. Designing interfaces with and without storyboards, plus Auto Layout, alerts, modals, and sheets. Handling mouse and keyboard events, animation, concurrency, and more. Hacking with macOS follows the same approach I used with Hacking with Swift: small, standalone projects that teach individual techniques starting from scratch, so you end up with a huge library of finished projects you can develop further or use as the base for something entirely new. If you loved Hacking with Swift, this is the sequel you've been waiting for.