Tutorial by Examples: on

Making an app adaptive – that is, responding to size class changes by changing your layout – often involves lots of help from the Auto Layout system. One of the primary ways apps become adaptive is by updating the active Auto Layout constraints when a view's size class changes. For example, conside...

A key piece of adaptivity in a modern iOS app is supporting multitasking on iPad. By default, apps created in Xcode 7 and newer will be configured to support multitasking: they'll have a LaunchScreen.storyboard file that uses Auto Layout. The easiest way for existing apps to opt in to multitasking ...

Considering a (post)model: public class User { public string FirstName { get; set; } public bool IsAdmin { get; set; } } With a view like so: @using (Html.BeginForm()) { @Html.EditorFor(model => model.FirstName) <input type="submit" value="Save" /...

The following is a list of tips for those who are looking to contribute to the PHP manual: Follow the manual's style guidelines. Ensure that the manual's style guidelines are always being followed for consistency's sake. Perform spelling and grammar checks. Ensure proper spelling and grammar is ...

Sometimes the shell prompt doesn't display the name of the virtual environment and you want to be sure if you are in a virtual environment or not. Run the python interpreter and try: import sys sys.prefix sys.real_prefix Outside a virtual, environment sys.prefix will point to the system p...

There are a few ways to use functions. Calling a function with an assignment statement DECLARE x NUMBER := functionName(); --functions can be called in declaration section BEGIN x := functionName(); END; Calling a function in IF statement IF functionName() = 100 THEN Null; EN...

A simple POST request with authentication data is demonstrated below, note that the username and password field will vary depending on the website: final String USER_AGENT = "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.103 Safari/537.36"; ...

Most websites require a much more complicated process than the one demonstrated above. Common steps for logging into a website are: Get the unique cookie from the initial login form. Inspect the login form to see what the destination url is for the authentication request Parse the login form t...

The built-in werkzeug server certainly is not suitable for running production servers. The most obvious reason is the fact that the werkzeug server is single-threaded and thus can only handle one request at a time. Because of this we want to use the uWSGI Server to serve our application instead. In...

The example in Visitor Pattern provides a compelling use-case for CRTP: struct IShape { virtual ~IShape() = default; virtual void accept(IShapeVisitor&) const = 0; }; struct Circle : IShape { // ... // Each shape has to implement this method the same way ...

In Object Oriented Programming a common task is to compose objects (values). In Functional Programming it is as common task to compose values as well as functions. We are used to compose values from our experience of other programming languages using operators like +, -, *, / and so on. Value co...

Assumptions: TableView - reference to the TableView DataSource - is a class which inherits UITableViewSource DataSource.Objects - is a public List< object >(), accessible to the UIViewController private UIRefreshControl refreshControl; public override void ViewDidLoad() { base.V...

Arrays Dim names = {"Foo", "Bar"} ' Inferred as String() Dim numbers = {1, 5, 42} ' Inferred as Integer() Containers (List(Of T), Dictionary(Of TKey, TValue), etc.) Dim names As New List(Of String) From { "Foo", "Bar" '... ...

You might expect a Python dictionary to be sorted by keys like, for example, a C++ std::map, but this is not the case: myDict = {'first': 1, 'second': 2, 'third': 3} print(myDict) # Out: {'first': 1, 'second': 2, 'third': 3} print([k for k in myDict]) # Out: ['second', 'third', 'first'] Py...

This example demonstrates POSIX Timer usage with CLOCK_REALTIME clock and SIGEV_THREAD notification method. #include <stdio.h> /* for puts() */ #include <string.h> /* for memset() */ #include <unistd.h> /* for sleep() */ #include <stdlib.h> /* for EXIT_SUCCESS */ #inc...

Here this will calculate the UTC time offset from current data in desired timezone. +(NSTimeInterval)getUTCOffSetIntervalWithCurrentTimeZone:(NSTimeZone *)current forDate:(NSDate *)date { NSTimeZone *utcTimeZone = [NSTimeZone timeZoneWithAbbreviation:@"UTC"]; NSInteger currentG...

If you wish to make a complete backup of a large MySql installation and do not have sufficient local storage, you can dump and compress it directly to an Amazon S3 bucket. It's also a good practice to do this without having the DB password as part of the command: mysqldump -u root -p --host=localho...

The UMD (Universal Module Definition) pattern is used when our module needs to be imported by a number of different module loaders (e.g. AMD, CommonJS). The pattern itself consists of two parts: An IIFE (Immediately-Invoked Function Expression) that checks for the module loader that is being i...

Immediately invoked function expressions can be used to create a private scope while producing a public API. var Module = (function() { var privateData = 1; return { getPrivateData: function() { return privateData; } }; })(); Module.getPrivateData(); // 1 Module.priva...

AMD is a module definition system that attempts to address some of the common issues with other systems like CommonJS and anonymous closures. AMD addresses these issues by: Registering the factory function by calling define(), instead of immediately executing it Passing dependencies as an array...