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

Question

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?

I know this question is kind of old but if you just use `RACSignal.combineLatest([self.textView.rac_textSignal(), RACObserve(self.textView, "text")]` yadda yadda yadda. That way you subscribe to both UI and programatic updates — barndog, Jan 11 '15 at 21:04

score 10 · Answer 1 · answered Mar 03 '15 at 12:32

10

Just send action:

[self.inputTextView sendActionsForControlEvents:UIControlEventEditingChanged];

answered Mar 03 '15 at 12:32

Ruslan Mansurov

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score 7 · Accepted Answer · answered Nov 25 '13 at 08:01

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.

score 0 · Answer 3 · answered Dec 22 '16 at 13:07

0

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.

answered Dec 22 '16 at 13:07

Stunner

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

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