CODEWITHSUNDEEP
iosobjective-cuitextfieldreactive-cocoa
bryanjclark
bryanjclark

Reputation: 6434

Reactive Cocoa - UITextView's rac_textSignal doesn't get called when programmatically setting text

I'm implementing a chat UI, and using Reactive Cocoa to adjust the chat bubble's size as the user types. Currently, I'm updating the UI's layout based on the textview's rac_textSignal. Everything's working great - except for one bit: when the user sends the message, I programmatically clear the textfield:

_inputTextView.text = @"";

... but the textview's rac_textSignal doesn't activate. I hear this is a feature with ReactiveCocoa - but what's the proper way to build this? Do I need to have an NSString holding the currentlyTypedString, and drive the UI changes when that string updates?

Upvotes: 7

Views: 2800

Answers (3)

Stunner
Stunner

Reputation: 12224

The following is a workaround that works:

[[RACSignal 
  merge:@[self.inputTextView.rac_textSignal, RACObserve(self.inputTextView, text)]] 
  subscribeNext:^(NSString* text) {
      // do something here
  }];

Thanks to startupthekid on GitHub.

Upvotes: 0

Ruslan Mansurov
Ruslan Mansurov

Reputation: 1301

Just send action:

[self.inputTextView sendActionsForControlEvents:UIControlEventEditingChanged];

Upvotes: 10

Justin Spahr-Summers
Justin Spahr-Summers

Reputation: 16973

Yep, that's correct.

Under MVVM, the view model should be considered the canonical source of UI data and events (which leads to a whole host of important benefits, like better testability). You'd store the typed NSString on the view model, then bind that to the UI.

With MVC, you'd have to use the controller or model instead, but the principle is the same: treat the view as transient data and do the important stuff elsewhere.

Upvotes: 7

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