https://github.com/aloco/reactivesecrets
A collection of ReactiveCocoa examples
https://github.com/aloco/reactivesecrets
Last synced: 5 months ago
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A collection of ReactiveCocoa examples
- Host: GitHub
- URL: https://github.com/aloco/reactivesecrets
- Owner: aloco
- License: mit
- Created: 2016-02-17T14:37:58.000Z (over 10 years ago)
- Default Branch: master
- Last Pushed: 2016-02-17T14:39:41.000Z (over 10 years ago)
- Last Synced: 2025-01-29T20:23:48.570Z (over 1 year ago)
- Size: 5.86 KB
- Stars: 6
- Watchers: 4
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
#ReactiveSecrets
I really like `ReactiveCocoa` and started using this framework in nearly all of my projects, however sometimes I had a hard time to find a reactive solution without help for easy looking tasks. Therefore I started this document to collect some use cases I stumbled across during development. This document should serves as a kind of cheat-cheet or as a best practice example collection.
Please note that this is not a pure beginners guide for `ReactiveCocoa` and requires that you have already read at least [Framework Overview](https://github.com/ReactiveCocoa/ReactiveCocoa/blob/master/Documentation/FrameworkOverview.md), [Basic Operators](https://github.com/ReactiveCocoa/ReactiveCocoa/blob/master/Documentation/BasicOperators.md) and
[Design Guidelines](https://github.com/ReactiveCocoa/ReactiveCocoa/blob/master/Documentation/DesignGuidelines.md)
 
# Table of Contents
1. [NSNotificationCenter](#nsnotificationcenter)
2. [Contributing](#contributing)
## NSNotificationCenter
Adjust scrollview when keyboard appears / disappears the reactive way.
```
NSNotificationCenter.defaultCenter()
.rac_notifications(UIKeyboardWillShowNotification, object: nil)
.startWithNext { [weak self] notification in
if let keyboardSize = notification.userInfo?[UIKeyboardFrameEndUserInfoKey]?.CGRectValue.size, let weakSelf = self {
var currentInset = weakSelf.tableView.contentInset
currentInset.bottom = keyboardSize.height
weakSelf.tableView.contentInset = currentInset
weakSelf.tableView.scrollIndicatorInsets = currentInset
}
}
```
Be aware, that **you have to cancel the subscription when it´s not longer needed.** `[weak self]` or `[unowned self]` within the closure does not cancel the subscription when e.g. the viewcontroller gets popped or dismissed.
Two possible solutions, as always there are more ways to do that..
**1. take care of your disposable**
```
let disposable = NSNotificationCenter.defaultCenter()
.rac_notifications(UIKey..........
```
>
hold a reference to the returned disposable and use `disposable.dispose()` to cancel the subscription
+ (+) very transparent
+ (+) manual control of subscription
+ (-) requires some boilerplate (e.g. holding reference of disposable)
**2. use `takeUntil` operator in combination with `rac_willDeallocSignal`**
>
`rac_willDeallocSignal` works only on `NSObject`. As another constraint, this operator returns an oldschool `RACSignal` which must be mapped to an `SignalProducer`. Time for an extension:
```
extension NSObject {
func rac_willDeallocSignalProducer() -> SignalProducer<(), NoError> {
return rac_willDeallocSignal()
.toSignalProducer()
.flatMapError { _ in .empty }
.map { _ in () }
}
}
```
> Then you can do
```
NSNotificationCenter.defaultCenter()
.rac_notifications(UIKeyboardWillShowNotification, object: nil)
.takeUntil(self.rac_willDeallocSignalProducer())
```
+ (+) automatically cancels the subscription when current object deallocs
+ (+) no boilerplate (except of optional `NSObject` extension)
+ (-/+) doesn´t work if you have accidently a strong reference to that object (e.g. caused by `self` caputred within a closure)
+ (-) works only with `NSObject`
**Complete solution with ``takeUntil``**
```
NSNotificationCenter.defaultCenter()
.rac_notifications(UIKeyboardWillShowNotification, object: nil)
.takeUntil(self.rac_willDeallocSignalProducer())
.startWithNext { [weak self] notification in
if let keyboardSize = notification.userInfo?[UIKeyboardFrameEndUserInfoKey]?.CGRectValue.size, let weakSelf = self {
var currentInset = weakSelf.tableView.contentInset
currentInset.bottom = keyboardSize.height
weakSelf.tableView.contentInset = currentInset
weakSelf.tableView.scrollIndicatorInsets = currentInset
}
}
```
# Contributing
If you want to help making this document a useful collection of `ReactiveCocoa` use cases, add new entries of your daily life reactive development or enhance existing examples 👍🏻
* [Fork it](http://help.github.com/forking/)
* Create new branch to make your changes / add your stuff
* Commit all your changes to your branch
* Submit a [pull request](http://help.github.com/pull-requests/)