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How to access a property value of AppDelegate class from someView Controller without creating reference of the delegate in view controller?

Sabha B
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3 Answers3

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I'm not quite sure what you mean - there are multiple ways to get information from your application delegate into a view controller, and the phrase "without creating reference of the delegate" is unclear. Your options basically are:

  1. Reference the application delegate, casting as appropriate. You would write code in your view controller class like: 
    id propertyValue = [(MyAppDelegate *)[[UIApplication sharedApplication] delegate] myProperty];
  2. Pass the property in when creating the view controller. This requires the view controller to have a @property declared and @synthesized for use, then you would have the app delegate just set the property on the view controller instance.

Neither of these options require that you retain a copy of your app's delegate as a @property, but the first does reference the delegate once.

Tim
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  • One more question [UIApplication sharedApplication].delegate; Is this a standrad way , why Am asking is I need a property called "sharedObject" in 3 different class files , "sharedObject" resides in AppDelegate class ? – Sabha B Mar 03 '11 at 02:39
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    Unless you want to create a singleton class to house the property, using `[[UIApplication sharedApplication] delegate]` is the standard way to access that property among multiple classes. (And let's be honest; you're basically accessing a singleton anyway. No need to multiply singletons.) – Tim Mar 03 '11 at 03:06
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[UIApplication sharedApplication].delegate

You'll also need to include the app delegate header file in your view controller and possibly typecast the delegate from id to your actual app delegate class.

#include "MyAppDelegate.h"

((MyAppDelegate *)[UIApplication sharedApplication].delegate).myProperty;
par
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[UIApplication sharedApplication].delegate;
madmik3
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  • Am looking for alternative way to achieve the same besides doing [UIApplication sharedApplication].delegate;. 1. Something like accessing the value through publish/subscribe? 2. One more question [UIApplication sharedApplication].delegate; Is this a standrad , way why Am asking is I need property called "sharedObject" in 3 different class files , "sharedObject" resides in AppDelegate class ? – Sabha B Mar 03 '11 at 02:37