当整数等于OSX中的某个特定值时，如何绑定控件中的隐藏属性？

Question

I've got a RadioGroup with 3 cells. I want to hide some controls when the selected index in radio group is 1. That is:

[someControl setHidden: radioGroup.selectedIndex == 1];

I've got a lot of controls will show/hidden when radio group selection changed. Some might show when the selected index equals 0, some might show when equals 2.

I want it to be done by binding, not connect each control reference using outlet.

How to acheive that?

Answer 1

There are at least two ways of doing this, as binding hidden requires a Boolean balue:

• Create a property that is of type BOOL and returns YES or NO based on your value comparison, then in your class use KVO to observe the original value and set the Boolean property inside of the KVO observer (this is required to make sure the object is updated at the right time)

• Use bindings alone, but create a Value Transformer to transform each value you need into a BOOL as necessary to be interpreted correctly. There is an existing value transformer that changes YES to NO and vice-versa, but for other value transforms you will have to create these yourself, and there is no good way to parametrize them inside of the xib file.

The first solution is probably easier.