colineberhardt / avalon Goto Github PK

Need to work out how this will be achieved, e.g. how to create a placeholder while images are loaded? what happens when cells are recycled?

See:

This should be supported by:

• UITableView
• UIPickerView
• UISegmentedControl

"ViewModelBase isn't doing KVO properly, you need to use a context parameter to ensure superclasses get called properly. It's not an issue given the current class hierarchy, but you're better off doing it the right way now instead of debugging it later, should the superclass change in the future. http://stackoverflow.com/a/11917449"

Remembering to correctly prefix their names (if necessary)

Because Avalon makes use of a number of Objective-C APIs (e.g. KVO, associated properties) it imposes a number of uncomfortable constraints. It would be great to be able to remove these at some point. Hopefully as the Swift language evolves, this will become possible!

• View models must extend NSObject because they are stored in an associated property via the bindingContext
• The ObservabeArray has to be a class, rather than a struct, because it is stored in associated properties. Swift structs cannot be bridged to Objective-C
• Numerous types are marked @objc in order that they can be used as associated properties (probably worth a review to check this is necessary in all cases)

Similar to the knockout concept, very useful for master-detail

The UIControl binding is disposed, but UIView is not.

Perhaps it would be better to have an observable array as an adapter over a strongly types swift array?

Due to the implementation of the overridden didMoveToWindow: method, it's currently possible for a delegateMultiplexer to be set as its own delegate. This in turn causes an infinite loop, and stack overflow.

There's a partial hotfix in: sammyd@a6bbd3a

if delegate !== delegateMultiplexer {
  delegateMultiplexer.delegate = delegate
  self.delegate = delegateMultiplexer
}

I think there are other code paths that could cause the same effect - maybe it would make sense for the multiplexer to reject a delegate value of itself?

UISegmentedControl has a bug, if you remove an item the selected item index is decremented. This causes quite a few issues with Avalon, where the selection index is maintained.

Affects

• UISearchBar
• UITableView

If you bind the selected index first, then the items, the initial selection state is incorrect:

segmentedControl.bindings = [Binding(source: "selectedOption", destination: "selectedSegmentIndex", mode: .TwoWay), 
   Binding(source: "options", destination: "segments")]

Need to cache the value.

It should be possible to specify that a bounds property is converted to a string via a formatter:

https://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/Strings/Articles/formatSpecifiers.html

When you pick a new value, an exception is thrown, something to do with the delegate multiplexer. First spotted in this commit:

8f9f4c3

As suggested by @sammyd - I think this sound viable.

This can be done by subscribing to the EditingDidEnd control event.

An exception is thrown here:

https://github.com/ColinEberhardt/Avalon/blob/master/Avalon/Util/Connectors/KVOBindingConnector.swift#L37

Provide binding support to the following:

UIView subclasses

• UILabel
• UIPickerView
• UIProgressView
• UIActivityIndicator
• UIImageView
• UITabBar
• UIToolbar
• UICollectionView
• UINavigationBar
• UITableViewCell
• UIActionSheet
• UIAlertView
• UIScrollView
• UITableView
• UITextView
• UISearchBar
• UIWebView

UIControl subclasses

• UIButton
• UIDatePicker
• UIPageControl
• UISegmentedControl
• UITextField
• UISlider
• UISwitch

Consider using custom operator functions to streamline Binding creation:

infix operator >| {}   // One-way binding
infix operator |<>| {} // Two-way binding

func >| (source: String, destination: String) -> Binding
{
    return Binding(source: source, destination: destination, mode: .OneWay)
}

func |<>| (source: String, destination: String) -> Binding
{
    return Binding(source: source, destination: destination, mode: .TwoWay)
}


    // bind the controls to the view model
//    searchBar.bindings = [Binding(source: "searchText", destination: "text", mode: .TwoWay),
//      Binding(source: "searchAction", destination: "searchAction")]
//
//    tableView.bindings = [Binding(source: "places", destination: "items"),
//      Binding(source: "placeSelectedAction", destination: "selectionAction")]

    searchBar.bindings = [
        "searchText" |<>| "text",
        "searchAction" >| "searchAction"
    ]

    tableView.bindings = [
        "places" >| "items",
        "placeSelectedAction" >| "selectionAction"
    ]

I neat idea via @ijoshsmith

Currently all bindings must be added before the bindingContext is set in order to create the binding.

These need to have they bindings evaluated.

One advantage is that it already has a registry concept built-in ..

• Change code to use NSValueTransformer
• revisit naming of converters
• Look at simplifying the implementation of transformers
• Unit test the transformer name look-up
• Determine whether the customer operators can be made to use the registry

Affects

• UIButton
• UIGestureRecognizer