Github url

KVOController

by facebookarchive

facebookarchive /KVOController

Simple, modern, thread-safe key-value observing for iOS and OS X.

7.2K Stars 903 Forks Last release: almost 4 years ago (v1.2.0) Other 157 Commits 6 Releases

Available items

No Items, yet!

The developer of this repository has not created any items for sale yet. Need a bug fixed? Help with integration? A different license? Create a request here:

KVOController

Build StatusCoverage StatusVersionPlatform

Key-value observing is a particularly useful technique for communicating between layers in a Model-View-Controller application. KVOController builds on Cocoa's time-tested key-value observing implementation. It offers a simple, modern API, that is also thread safe. Benefits include:

  • Notification using blocks, custom actions, or NSKeyValueObserving callback.
  • No exceptions on observer removal.
  • Implicit observer removal on controller dealloc.
  • Thread-safety with special guards against observer resurrection – rdar://15985376.

For more information on KVO, see Apple's Introduction to Key-Value Observing.

Usage

Example apps for iOS and OS X are included with the project. Here is one simple usage pattern:

// create KVO controller with observer FBKVOController \*KVOController = [FBKVOController controllerWithObserver:self]; self.KVOController = KVOController; // observe clock date property [self.KVOController observe:clock keyPath:@"date" options:NSKeyValueObservingOptionInitial|NSKeyValueObservingOptionNew block:^(ClockView \*clockView, Clock \*clock, NSDictionary \*change) { // update clock view with new value clockView.date = change[NSKeyValueChangeNewKey]; }];

While simple, the above example is complete. A clock view creates a KVO controller to observe the clock date property. A block callback is used to handle initial and change notification. Unobservation happens implicitly on controller deallocation, since a strong reference to the

KVOController

is kept.

Note: the observer specified must support weak references. The zeroing weak reference guards against notification of a deallocated observer instance.

NSObject Category

For an even easier usage, just

#import <kvocontroller></kvocontroller>

for an automatic

KVOController

property on all objects.

[self.KVOController observe:clock keyPath:@"date" options:NSKeyValueObservingOptionInitial|NSKeyValueObservingOptionNew action:@selector(updateClockWithDateChange:)];

Swift

KVOController works great in Swift but there are few requirements:

  • Your observer should subclass
    NSObject
    .
  • Properties that you observe must be marked as
    dynamic
    .

Check the following example:

class TasksListViewModel: NSObject { dynamic var tasksList: [TaskList] = [] } /// In ViewController.swift import KVOController kvoController.observe(viewModel, keyPath: "listsDidChange", options: [.new, .initial]) { (viewController, viewModel, change) in self.taskListsTableView.reloadData() }

Prerequisites

KVOController takes advantage of recent Objective-C runtime advances, including ARC and weak collections. It requires:

  • iOS 6 or later.
  • OS X 10.7 or later.

Installation

To install using CocoaPods, add the following to your project Podfile:

pod 'KVOController'

To install using Carthage, add the following to your project Cartfile:

github "facebook/KVOController"

Alternatively, drag and drop FBKVOController.h and FBKVOController.m into your Xcode project, agreeing to copy files if needed. For iOS applications, you can choose to link against the static library target of the KVOController project.

Having installed using CocoaPods or Carthage, add the following to import in Objective-C: ```objective-c

import

## Testing The unit tests included use CocoaPods for managing dependencies. Install CocoaPods if you haven't already done so. Then, at the command line, navigate to the root KVOController directory and type: ```sh pod install

This will install and add test dependencies on OCHamcrest and OCMockito. Re-open the Xcode KVOController workspace and Test, ⌘U.

License

KVOController is released under a BSD License. See LICENSE file for details.

We use cookies. If you continue to browse the site, you agree to the use of cookies. For more information on our use of cookies please see our Privacy Policy.