IOS 7 UISearchDisplayController search bar overlaps status bar while searching

You can achieve this by implementing a new property called edgesForExtendedLayout in iOS7 SDK. Please add the following code to achieve this,

if ([self respondsToSelector:@selector(edgesForExtendedLayout)])
        self.edgesForExtendedLayout = UIRectEdgeNone;

You need to add the above in your -(void)viewDidLoad method.

iOS 7 brings several changes to how you layout and customize the appearance of your UI. The changes in view-controller layout, tint color, and font affect all the UIKit objects in your app. In addition, enhancements to gesture recognizer APIs give you finer grained control over gesture interactions.

Using View Controllers

In iOS 7, view controllers use full-screen layout. At the same time, iOS 7 gives you more granular control over the way a view controller lays out its views. In particular, the concept of full-screen layout has been refined to let a view controller specify the layout of each edge of its view.

The wantsFullScreenLayout view controller property is deprecated in iOS 7. If you currently specify wantsFullScreenLayout = NO, the view controller may display its content at an unexpected screen location when it runs in iOS 7.

To adjust how a view controller lays out its views, UIViewController provides the following properties:

• edgesForExtendedLayout

The edgesForExtendedLayout property uses the UIRectEdge type, which specifies each of a rectangle’s four edges, in addition to specifying none and all. Use edgesForExtendedLayout to specify which edges of a view should be extended, regardless of bar translucency. By default, the value of this property is UIRectEdgeAll.

• extendedLayoutIncludesOpaqueBars

If your design uses opaque bars, refine edgesForExtendedLayout by also setting the extendedLayoutIncludesOpaqueBars property to NO. (The default value of extendedLayoutIncludesOpaqueBars is NO.)

• automaticallyAdjustsScrollViewInsets

If you don’t want a scroll view’s content insets to be automatically adjusted, set automaticallyAdjustsScrollViewInsets to NO. (The default value of automaticallyAdjustsScrollViewInsets is YES.)

• topLayoutGuide, bottomLayoutGuide

The topLayoutGuide and bottomLayoutGuide properties indicate the location of the top or bottom bar edges in a view controller’s view. If bars should overlap the top or bottom of a view, you can use Interface Builder to position the view relative to the bar by creating constraints to the bottom of topLayoutGuide or to the top of bottomLayoutGuide. (If no bars should overlap the view, the bottom of topLayoutGuide is the same as the top of the view and the top of bottomLayoutGuide is the same as the bottom of the view.) Both properties are lazily created when requested.

Please refer, apple doc

1. Set the UIViewControllerBasedStatusBarAppearance to YES in the .plist file.

2. In the viewDidLoad do a [self setNeedsStatusBarAppearanceUpdate];

3. Add the following method:

   - (UIStatusBarStyle)preferredStatusBarStyle
   { 
       return UIStatusBarStyleLightContent; 
   }
   

Note: This does not work for controllers inside UINavigationController, please see Tyson's comment below :)

Swift 3 - This will work controllers inside UINavigationController. Add this code inside your controller.

// Preferred status bar style lightContent to use on dark background.
// Swift 3
override var preferredStatusBarStyle: UIStatusBarStyle {
    return .lightContent
}

Swift 5 and SwiftUI

For SwiftUI create a new swift file called HostingController.swift

import Foundation
import UIKit
import SwiftUI

class HostingController: UIHostingController<ContentView> {
    override var preferredStatusBarStyle: UIStatusBarStyle {
        return .lightContent
    }
}

Then change the following lines of code in the SceneDelegate.swift

window.rootViewController = UIHostingController(rootView: ContentView())

to

window.rootViewController = HostingController(rootView: ContentView())