Two way binding when setter is overriden

Posted by Nicolas Goy on Stack Overflow See other posts from Stack Overflow or by Nicolas Goy
Published on 2012-10-25T22:57:14Z Indexed on 2012/10/25 23:00 UTC
Read the original article Hit count: 200

Filed under:

cocoa

|

properties

|

key-value-observing

I have an NSTextField bound to some object "zoom" property.

In this object's class implementation, I have the following

- (void)setZoom:(CGFloat)zoom
{
    _zoom = MAX(0, MIN(10, zoom));
}

If I write "-5" in the textfield, setZoom: will be called with "-5" as argument and _zoom will be set to 0.

Then problem is that the textfield is not updating itself and it shows "-5" instead of re-reading the property value it has just set.

If I do myObject.zoom = -5; in code, the text field will display 0 correctly.

I tried to wrap _zoom =... inside willChangeValueForKey/didChangeValueForKey calls but it didn't change anything.

© Stack Overflow or respective owner

Related posts about cocoa

MVC - Cocoa interface - Cocoa Design pattern book

as seen on Stack Overflow - Search for 'Stack Overflow'
So I started reading this book: http://www.amazon.com/Cocoa-Design-Patterns-Erik-Buck/dp/0321535022 On chapter 2 it explains about the MVC design pattern and gives and example which I need some clarification to. The simple example shows a view with the following fields: hourlyRate, WorkHours, Standarthours… >>> More
Drag String data from My Cocoa App to Third-Party Cocoa App

as seen on Stack Overflow - Search for 'Stack Overflow'
Hello, I want to drag a row from my tableview and drop it into any other NSTextField in Mac OS X 10.6, and have a string of text be dropped. Drag and drop already works within my app (between a NSTableView and an NSBrowser), but I have had no success putting any data on the pasteboard that can… >>> More
Cocoa equivalent of the Carbon method getPtrSize

as seen on Stack Overflow - Search for 'Stack Overflow'
I need to translate the a carbon method into cocoa into and I am having trouble finding any documentation about what the carbon method getPtrSize really does. From the code I am translating it seems that it returns the byte representation of an image but that doesn't really match up with the name… >>> More
String formatting in cocoa

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi I am trying to send some text in an email from my cocoa app (by using Mail.app). Initially I tried using HTML to send properly formatted text. But the mailto: URL does not support html tags (even after setting headers) So I decided to use formatted string (left-aligning of string) This is what… >>> More
Anyone know the state of cocoa#?

as seen on Stack Overflow - Search for 'Stack Overflow'
Having just updated Mono to 2.6.3 (on OS X), I noticed in the installer that cocoa# 0.9.5 is also installed. However using MonoDevelop there are no cocoa# project templates by default, and I was wondering if anyone knew more about creating cocoa# apps. If you goto the cocoa# page on the Mono site… >>> More

Related posts about properties

Creating a dynamic, extensible C# Expando Object

as seen on West-Wind - Search for 'West-Wind'
I love dynamic functionality in a strongly typed language because it offers us the best of both worlds. In C# (or any of the main .NET languages) we now have the dynamic type that provides a host of dynamic features for the static C# language. One place where I've found dynamic to be incredibly useful… >>> More
Loading Properties with Spring (via System Properties)

as seen on Stack Overflow - Search for 'Stack Overflow'
My problem is as follows: I have server.properties for different environments. The path to those properties is provided trough a system property called propertyPath. How can I instruct my applicationContext.xml to load the properties with the given propertyPath system property without some ugly MethodInvokingBean… >>> More
Java properties - .properties files vs xml?

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm a newbie when it comes to properties, and I read that XML is the preferred way to store these. I noticed however, that writing a regular .properties file in the style of foo=bar fu=baz also works. This would mean a lot less typing (and maybe easier to read and more efficient as well). So what… >>> More
How to make Delphi Prism indexed properties visible to C# when properties are not default

as seen on Stack Overflow - Search for 'Stack Overflow'
I have several Delphi Prism classes with indexed properties that I use a lot on my C# web applications (we are migrating a big Delphi Win32 system to ASP.Net). My problem is that it seems that C# can't see the indexed properties if they aren't the default properties of their classes. Maybe I'm doing… >>> More
properties-maven-plugin: Error loading properties-file

as seen on Stack Overflow - Search for 'Stack Overflow'
I want to extract all the properties from my pom.xml into a properties-file. These are the common properties like dependency-versions, plugin-versions and directories. I'm using the properties-maven-plugin, but its not working as i want it to. The essential part of my pom.xml: <plugin> <groupId>org… >>> More