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objective-cios7ios7.1

makeObjectsPerformSelector not working on IOS7.1

i have array of buttons (IBOutletCollections) name "topFriends"..i need to set hidden the all buttons of topFriends(array name).

[self.topInFriends makeObjectsPerformSelector:@selector(setHidden:) withObject:[NSNumber numberWithBool:YES]];

Actually its working on iOS7...but its not working on iOS 7.1 .

but when i try to enumerate the array like following,then its working for iOS7 and 7.1

[self.topInFriends enumerateObjectsUsingBlock:^(UIButton * obj, NSUInteger idx, BOOL *stop) {
        obj.hidden=YES;
    }];

Can anyone please tell me why makeObjectsPerformSelector function not working in iOS 7.1 .I am really frustrated to find the issue..please anyone help me..thanks in advance

Solution

  • I got this from the docs of makeObjectsPerformSelector and this is the description of the parameter SEL in this method

    A selector that identifies the message to send to the objects in the array. The method must take a single argument of type id, and must not have the side effect of modifying the receiving array.

    Then I run this line

    [self.topInFriends makeObjectsPerformSelector:@selector(setHidden:)
                                   withObject:@"Fcuked up"];

    It hides the button, So it doesn't matter what you are passing. And it makes sense too as your method expect a BOOL and you are giving an object to it, I don't know the exact internal implementation of makeObjectsPerformSelector but I can conclude some points

    When you pass some object say @"abc" or @YES and when makeObjectsPerformSelector invokes your setHidden then it's passing object, which obviously has some address too, to setHidden and it converts your object(address) into BOOL. Suppose your addresses are

    @"Fcuked up" ---> 0x7cde450034798976  (assuming 64 bit pointer)
@YES         ---> 0x7cde450000000000

    For first case the value of BOOL will become true as it's LSB are non-zero and for second case the BOOL will become false as LSB are zeros.

    In whole you should respect apple docs and you should not call a method which doesn't take parameter as id

    All thoughts appearing in this answer are mine. Any resemblance to other persons, living or dead, is purely coincidental.