Tutorial by Examples: en

Because in .NET 3.5 and older you don't have Lazy<T> class you use the following pattern: public class Singleton { private Singleton() // prevents public instantiation { } public static Singleton Instance { get { return Nested.instanc...

All collection objects contain a map method that takes a Function as an argument, which must take a single argument. This returns an Iterable backed by the collection. When the Iterable is iterated, each step calls the function with a new element of the collection, and the result of the call becomes...

Once the number of abilities definitions start to grow in number, it becomes more and more difficult to handle the Ability file. The first strategy to handle these issue is to move abilities into meaningful methods, as per this example: class Ability include CanCan::Ability def initialize(...

Step 1: Create the controller, set the delegate, and conform to the protocol //Swift class ImageUploadViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate { let imagePickerController = UIImagePickerController() override func viewDi...

Although it's bad practice, it's possible to add multiple return statements in a exception handling block: public static int returnTest(int number){ try{ if(number%2 == 0) throw new Exception("Exception thrown"); else return x; } catch(Exception e){ ...

LISP and Scheme's greatest advantage over other mainstream programming language is their macro system. Unlike the C preprocessor and other macro languages, Scheme macros take parsed code as input and return expanded code as output. This is one of the applications of Scheme's “code is data” phrase, a...

Method stopLoading() stops the current loading process of the webview. Swift webview.stopLoading() Objective-C [webview stopLoading];

Swift webview.reload() Objective-C [webview reload];

Using natural language Functions calls should be close to natural English language. Example: list.insert(element, at: index) instead of list.insert(element, position: index) Naming Factory Methods Factory methods should begin with the prefix `make`. Example: factory.makeObject() ...

By default, one should subscribe to event using inspector, but sometimes it's better to do it in code. In this example we subscribe to click event of a button in order to handle it. using UnityEngine; using UnityEngine.UI; [RequireComponent(typeof(Button))] public class AutomaticClickHandler :...

In case we want to use enum with more information and not just as constant values, and we want to be able to compare two enums. Consider the following example: public enum Coin { PENNY(1), NICKEL(5), DIME(10), QUARTER(25); private final int value; Coin(int value){ this....

To split a JID into its component parts (the localpart, domainpart, and resourcepart), the following algorithm should be used (where the localpart is represented by lp, the resourcepart by rp, and the domainpart by dp and ∈ is used to check if the given character is included in the string): Note ...

In a module (library or application) where you need the aar file you have to add in your build.gradle the repository: repositories { flatDir { dirs 'libs' } } and add the dependency: dependencies { compile(name:'nameOfYourAARFileWithoutExtension', ext:'aar') } Pay a...

The aar file doesn't contain the transitive dependencies and doesn't have a pom file which describes the dependencies used by the library. It means that, if you are importing a aar file using a flatDir repo you have to specify the dependencies also in your project. You should use a maven repositor...

Object obj = new Object(); // Note the 'new' keyword Where: Object is a reference type. obj is the variable in which to store the new reference. Object() is the call to a constructor of Object. What happens: Space in memory is allocated for the object. The constructor Object() is call...

Simple Example (centering a single element) HTML <div class="aligner"> <div class="aligner-item">…</div> </div> CSS .aligner { display: flex; align-items: center; justify-content: center; } .aligner-item { max-width: 50%; /*for d...

Sass uses the colon (:) operator to assign values to variables. Example $foreColor: red; p { color: $foreColor; }

A Button directive which accepts an @Input() to specify a click limit until the button gets disabled. The parent component can listen to an event which will be emitted when the click limit is reached via @Output: import { Component, Input, Output, EventEmitter } from '@angular/core'; @Component(...

It is possible to upload multiple parts, each with a different name. For each part name, you will need one parameter annotated with @RequestPart, whose name matches the part name. To receive a file uploaded via an HTTP Post, you need to do the following: @RequestMapping( value = "...&quo...

C++11 The type std::conditional in the standard library header <type_traits> can select one type or the other, based on a compile-time boolean value: template<typename T> struct ValueOrPointer { typename std::conditional<(sizeof(T) > sizeof(void*)), T*, T>::type vop; }...