stackoverflow-tag-objective-c

stackoverflow-tag-objective-c-1

1.How do I convert an NSString value to NSData?
NSString* str = @"teststring";
NSData* data = [str dataUsingEncoding:NSUTF8StringEncoding];

2.How to check iOS version?
[[UIDevice currentDevice].systemVersion floatValue]

3.How do I create delegates in Objective-C?
http://stackoverflow.com/questions/626898/how-do-i-create-delegates-in-objective-c

4.Location Services not working in iOS 8？
http://stackoverflow.com/questions/24062509/location-services-not-working-in-ios-8

5.How do you trigger a block after a delay, like -performSelector:withObject:afterDelay:?
int parameter1 = 12;
float parameter2 = 144.1;

// Delay execution of my block for 10 seconds.
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, 10 * NSEC_PER_SEC), dispatch_get_main_queue(), ^{
    NSLog(@"parameter1: %d parameter2: %f", parameter1, parameter2);
});


let time1 = 8.23
let time2 = 3.42

// Delay 2 seconds
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, Int64(2.0 * Double(NSEC_PER_SEC))), dispatch_get_main_queue()) { () -> Void in
        println("Sum of times: \(time1 + time2)")
}

+ (void)runBlock:(void (^)())block
{
    block();
}
+ (void)runAfterDelay:(CGFloat)delay block:(void (^)())block 
{
    void (^block_)() = [[block copy] autorelease];
    [self performSelector:@selector(runBlock:) withObject:block_ afterDelay:delay];
}

[Util runAfterDelay:2 block:^{
    NSLog(@"two seconds later!");
}];


6.how to make a Placeholder in UITextView?
http://stackoverflow.com/questions/1328638/placeholder-in-uitextview 

7.In Objective-C, how do I test the object type?
http://stackoverflow.com/questions/1144629/in-objective-c-how-do-i-test-the-object-type

8.UIView with rounded corners?
http://stackoverflow.com/questions/1509547/uiview-with-rounded-corners

9.How to print out the method name and line number and conditionally disable NSLog?
http://stackoverflow.com/questions/969130/how-to-print-out-the-method-name-and-line-number-and-conditionally-disable-nslog

10.How to check if an NSDictionary or NSMutableDictionary contains a key?
http://stackoverflow.com/questions/2784648/how-to-check-if-an-nsdictionary-or-nsmutabledictionary-contains-a-key

11.Is It Possible to NSLog C Structs (Like CGRect or CGPoint)?
http://stackoverflow.com/questions/550195/is-it-possible-to-nslog-c-structs-like-cgrect-or-cgpoint

12.Set the maximum character length of a UITextField?
http://stackoverflow.com/questions/433337/set-the-maximum-character-length-of-a-uitextfield