How To Hide Status Bar In iOS 7

- (BOOL)prefersStatusBarHidden
{
   return YES;
}

Write above method on every UIViewController class which has a UIView to show without status bar.

isDescendantOfView: To check whether UIView is a subview of another UIView in iOS

Sometimes it's needed to check whether a UIView is a subview of another view. A typical use case is show and hide UIViews with button click events. it's better if the code check whether a UIView is a sub view of another view before the view is removed from the super view. UIView class have method  "isDescendantOfView" [1] it returns "YES" if the specified UIView is a subview of another UIView if it's not it returns "NO".

In example code below, "I m in" is printed if the theSubView is a sub view of the UIView self.view otherwise it prints "I m out".

if ([theSubView isDescendantOfView:self.view]) {

    

        NSLog(@"I m in");

        

    }else{

    

        NSLog(@"I m out");

    

    }

Reference:
[1]. http://developer.apple.com/library/ios/documentation/uikit/reference/uiview_class/uiview/uiview.html#//apple_ref/occ/instm/UIView/isDescendantOfView:

Converting NSString to NSData and NSData to NSString

Description

Below code segment shows how to convert a NSString value to NSData and NSData value to NSString value. At the beginning, It create a NSString literal with the variable name "firstString" then value of "firstString" variable is taken as a way that can be assigned into NSData variable by using method [1]. The variable "firstString" is assigned with "nil" in order to show that the variable contains nothing. The value of the variable has printed to by using "NSLog". After the printing a NSString object is created with by using previously created NSData. Method [2] has been used. Then the "firstString" value is printed again with NSLog.

1. - (NSData *)dataUsingEncoding:(NSStringEncoding)encoding
2. - (instancetype)initWithData:(NSData *)data encoding:(NSStringEncoding)encoding

Code

    NSString *firstString = @"This is the string that is wanted to convert";

    

    NSData *dataFromString = [firstString dataUsingEncoding:NSUTF8StringEncoding];

    

    firstString = nil;

    

    NSLog(@"firstString (nil) = %@", firstString);

    

    firstString = [[NSString alloc] initWithData:dataFromString encoding:NSUTF8StringEncoding];

    

    NSLog(@"firstString (!nil) = %@", firstString);

Result

2014-03-24 17:10:11.367 TestProject[3048:60b] firstString (nil) = (null)

2014-03-24 17:10:11.369 TestProject[3048:60b] firstString (!nil) = This is the string that is wanted to convert