Tutorial by Examples: n

What is Serialization Serialization is the process of converting an object's state (including its references) to a sequence of bytes, as well as the process of rebuilding those bytes into a live object at some future time. Serialization is used when you want to persist the object. It is also used b...

If you have cloned a fork (e.g. an open source project on Github) you may not have push access to the upstream repository, so you need both your fork but be able to fetch the upstream repository. First check the remote names: $ git remote -v origin https://github.com/myusername/repo.git (fetch...

Installing Visual Studio If you do not have Visual Studio installed, you can download the free Visual Studio Community Edition here. If you already have it installed, you can proceed to the next step. Creating an ASP.NET Core MVC Application. Open Visual Studio. Select File > New Project. ...

By default, all the methods declared in a protocol are required. This means that any class that conforms to this protocol must implement those methods. It is also possible to declare optional methods. These method can be implemented only if needed. You mark optional methods with the @optional dire...

The following syntax indicate that a class adopts a protocol, using angle brackets. @interface NewClass : NSObject <NewProtocol> ... @end This means that any instance of NewClass will respond to methods declared in its interface but also it will provide an implementation for all the requ...

If you screw up a rebase, one option to start again is to go back to the commit (pre rebase). You can do this using reflog (which has the history of everything you've done for the last 90 days - this can be configured): $ git reflog 4a5cbb3 HEAD@{0}: rebase finished: returning to refs/heads/foo 4...

The typeof operator works on type parameters. class NameGetter<T> { public string GetTypeName() { return typeof(T).Name; } }

toList flattens a Foldable structure t a into a list of as. ghci> toList [7, 2, 9] -- t ~ [] [7, 2, 9] ghci> toList (Right 'a') -- t ~ Either e "a" ghci> toList (Left "foo") -- t ~ Either String [] ghci> toList (3, True) -- t ~ (,) Int [True] toList is ...

When json_encode or json_decode fails to parse the string provided, it will return false. PHP itself will not raise any errors or warnings when this happens, the onus is on the user to use the json_last_error() and json_last_error_msg() functions to check if an error occurred and act accordingly in ...

It is possible to instruct the Xamarin.Android Bindings Generator to ignore a Java type and not bind it. This is done by adding a remove-node XML element to the metadata.xml file: <remove-node path="/api/package[@name='{package_name}']/class[@name='{name}']" />

Interactive input To get input from the user, use the input function (note: in Python 2.x, the function is called raw_input instead, although Python 2.x has its own version of input that is completely different): Python 2.x2.3 name = raw_input("What is your name? ") # Out: What is your...

VoiceOver works great most of the time, breezily reading aloud screens full of content and intuitively following the user. Alas, no general solution is perfect. Sometimes only you, the app developer, know where VoiceOver should be focused for an optimal user experience. Fortunately, VoiceOver listen...

In many cases, content within a single screen will update with new or different content. For example, imagine a form that reveals additional options based on the user’s answer to a previous question. In this case, a “layout change” notification lets you either announce the change or focus on a new e...

Announcements are useful for alerting users to events that don’t require any interaction, such as “screen locked” or “finished loading.” Use a more specific announcement to notify users of screen changes or more minor layout changes. UIAccessibilityPostNotification(UIAccessibilityAnnouncementNotifi...

VoiceOver navigates from top-left to bottom-right, irrespective of the view hierarchy. This is usually how content is arranged in left-to-right languages since sighted individuals tend to scan the screen in an “F-shaped pattern”. VoiceOver users will expect to navigate the same way as typical users....

VoiceOver can navigate many apps on iOS because most UIKit classes implement UIAccessibilityProtocol. Features that don’t represent onscreen elements using UIView, including apps that leverage Core Graphics or Metal to perform drawing, must describe these elements for accessibility. As of iOS 8.0, t...

Most UIKit classes, including UIView, adhere to UIAccessibilityProtocol and return correct values by default. It’s easy to take for granted that a UIView set to hidden is also absent from the accessibility hierarchy and won’t be navigated by VoiceOver. While this default behavior is usually sufficie...

1.8 You can remove a submodule (e.g. the_submodule) by calling: $ git submodule deinit the_submodule $ git rm the_submodule git submodule deinit the_submodule deletes the_submodules' entry from .git/config. This excludes the_submodule from git submodule update, git submodule sync and git ...

IDLE is Python’s Integrated Development and Learning Environment and is an alternative to the command line. As the name may imply, IDLE is very useful for developing new code or learning python. On Windows this comes with the Python interpreter, but in other operating systems you may need to install...

You can use a template in a function based view as follows: from django.shortcuts import render def view(request): return render(request, "template.html") If you want to use template variables, you can do so as follows: from django.shortcuts import render def view(request):...