Setting leftViewMode/rightViewMode on UITextField causing iOS application to hang

[jordanmaguire]

If in my stylesheet I have something like:

style :textField,
    backgroundColor: UIColor.whiteColor,
    leftView: UIView.alloc.initWithFrame(CGRectMake(0,0,20,44)),
    leftViewMode: UITextFieldViewModeAlways,
    rightView: UIView.alloc.initWithFrame(CGRectMake(0,0,20,44)),
    rightViewMode: UITextFieldViewModeAlways

and apply that to an instance of a UITextField, my app dies with no error. The REPL becomes unresponsive and I have to force the simulator to quit.

If I don't set the leftViewMode or rightViewMode in the styles, and just set them on the instance itself, it all works fine.

I'm using:

• iOS7
• RubyMotion 2.24
• Teacup 2.1.16

Easy enough to work around. However, seems like something weird must be happening behind the scenes given this is no different from any other assignment.

[jordanmaguire]

Actually I'll investigate some more, might be another gem causing this issue.

[jordanmaguire]

For anyone running into a similar issue:

Looks like you should NOT instantiate objects as I was doing there. It will just return the same object every time. Makes sense.

You'll need to do the following, instead:

style :textField,
    backgroundColor: UIColor.whiteColor,
    leftView: lambda { UIView.alloc.initWithFrame(CGRectMake(0,0,20,44)) },
    rightView: lambda { UIView.alloc.initWithFrame(CGRectMake(0,0,20,44)) }

That way you get a new object every time, instead of the same one. That's why it was crashing out when I was changing the leftViewMode/rightViewMode on any views that used that style other than the first one.

Without lambda:

(main)> Controller.current.view.nameField.leftView
=> #<UIView:0x94cc2b0>
(main)> Controller.current.view.emailField.leftView
=> #<UIView:0x94cc2b0>

With lambda:

(main)> Controller.current.view.emailField.leftView
=> #<UIView:0xa9889b0>
(main)> Controller.current.view.nameField.leftView
=> #<UIView:0xa98b3b0>

[colinta]

Ah, yes, I'll document that lambda support in the README, and point out that if you need to create an object, that's the way to do it.