Tutorial by Examples: i

Predefined macros are those that the compiler defines (in contrast to those user defines in the source file). Those macros must not be re-defined or undefined by user. The following macros are predefined by the C++ standard: __LINE__ contains the line number of the line this macro is used on, an...

To show some content in a new window, a Stage needs to be created. After creation and initialisation show or showAndWait needs to be called on the Stage object: // create sample content Rectangle rect = new Rectangle(100, 100, 200, 300); Pane root = new Pane(rect); root.setPrefSize(500, 500); ...

If you have an existing class that you'd like to use, perform Step 2 and then skip to Step 5. (For some cases, I had to add an explicit #import <Foundation/Foundation.h to an older ObjC File) Step 1: Add Objective-C Implementation -- .m Add a .m file to your class, and name it CustomObje...

Step 1: Create New Swift Class Add a .swift file to your project, and name it MySwiftObject.swift In MySwiftObject.swift: import Foundation class MySwiftObject : NSObject { var someProperty: AnyObject = "Some Initializer Val" init() {} func someFunction(someArg...

# app/channels/appearance_channel.rb class NotificationsChannel < ApplicationCable::Channel def subscribed stream_from "notifications" end def unsubscribed end def notify(data) ActionCable.server.broadcast "notifications", { title: 'New things!', ...

app/assets/javascripts/channels/notifications.coffee App.notifications = App.cable.subscriptions.create "NotificationsChannel", connected: -> # Called when the subscription is ready for use on the server $(document).on "change", "input", (e)=> ...

Java-like enumerations can be created by extending Enumeration. object WeekDays extends Enumeration { val Mon, Tue, Wed, Thu, Fri, Sat, Sun = Value } def isWeekend(day: WeekDays.Value): Boolean = day match { case WeekDays.Sat | WeekDays.Sun => true case _ => false } isWeekend...

An alternative to extending Enumeration is using sealed case objects: sealed trait WeekDay object WeekDay { case object Mon extends WeekDay case object Tue extends WeekDay case object Wed extends WeekDay case object Thu extends WeekDay case object Fri extends WeekDay case objec...

Creating a Snackbar can be done as follows: Snackbar.make(view, "Text to display", Snackbar.LENGTH_LONG).show(); The view is used to find a suitable parent to use to display the Snackbar. Typically this would be a CoordinatorLayout that you've defined in your XML, which enables adding ...

The String List passed as a parameter to the share() method contains the paths of all the files you want to share. It basically loops through the paths, adds them to Uri, and starts the Activity which can accept Files of this type. public static void share(AppCompatActivity context,List<Strin...

Functions can either be named or unnamed (anonymous functions): var namedSum = function sum (a, b) { // named return a + b; } var anonSum = function (a, b) { // anonymous return a + b; } namedSum(1, 3); anonSum(1, 3); 4 4 But their names are private to their own scope: ...

To avoid verbose null checking, the ?. operator has been introduced in the language. The old verbose syntax: If myObject IsNot Nothing AndAlso myObject.Value >= 10 Then Can be now replaced by the concise: If myObject?.Value >= 10 Then The ? operator is particularly powerful when you...

This new feature makes the string concatenation more readable. This syntax will be compiled to its equivalent String.Format call. Without string interpolation: String.Format("Hello, {0}", name) With string interpolation: $"Hello, {name}" The two lines are equivalent and ...

There are 4 methods for comparing dates: Swift isEqualToDate(anotherDate: NSDate) -> Bool earlierDate(anotherDate: NSDate) -> NSDate laterDate(anotherDate: NSDate) -> NSDate compare(anotherDate: NSDate) -> NSComparisonResult Objective-C - (BOOL)isEqualToDate:(NSDate *)anothe...

Get the description of an specific property in an object. var sampleObject = { hello: 'world' }; Object.getOwnPropertyDescriptor(sampleObject, 'hello'); // Object {value: "world", writable: true, enumerable: true, configurable: true}

Swift let alert = UIAlertController(title: "Hello", message: "Welcome to the world of iOS", preferredStyle: UIAlertControllerStyle.alert) let defaultAction = UIAlertAction(title: "OK", style: UIAlertActionS...

Dim array() As Integer = {2, 0, 1, 6} ''Initialize an array of four Integers. Dim strings() As String = {"this", "is", "an", "array"} ''Initialize an array of four Strings. Dim floats() As Single = {56.2, 55.633, 1.2, 5.7743, 22.345} ...

Compare method Either you implement a compare-method for your object: - (NSComparisonResult)compare:(Person *)otherObject { return [self.birthDate compare:otherObject.birthDate]; } NSArray *sortedArray = [drinkDetails sortedArrayUsingSelector:@selector(compare:)]; NSSortDescriptor NSS...

Custom Font Support Applications that want to use custom fonts can now include those fonts in their application bundle and register those fonts with the system by including the UIAppFonts key in their Info.plist file. The value of this key is an array of strings identifying the font files in the ...

We write custom action filters for various reasons. We may have a custom action filter for logging, or for saving data to database before any action execution. We could also have one for fetching data from the database and setting it as the global values of the application. To create a custom actio...