我使用Quartz创建了一个渐变，只有一个问题。我无法通过屏幕旋转它。我已经尝试了this tutorial上列出的所有内容。这是视图控制器头：
#import <UIKit/UIKit.h>
@interface RadialGradientBackgroundViewController : UIViewController {
}
@end
这是视图控制器：
#import "RadialGradientBackgroundViewController.h"
#import "BackgroundLayer.h"
@implementation RadialGradientBackgroundViewController
/*
// The designated initializer. Override to perform setup that is required before the view is loaded.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
*/
/*
// Implement loadView to create a view hierarchy programmatically, without using a nib.
- (void)loadView {
}
*/
- (void)viewDidLoad {
[super viewDidLoad];
}
-(void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
CAGradientLayer *bgLayer = [BackgroundLayer gradient];
bgLayer.frame = self.view.bounds;
[self.view.layer insertSublayer:bgLayer atIndex:0];
}
-(void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration {
[[[self.subview.layer sublayers] objectAtIndex:0] setFrame:self.view.bounds]; // Error is here!
}
/*
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
// Return YES for supported orientations
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
*/
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
- (void)viewDidUnload {
}
- (void)dealloc {
[super dealloc];
}
@end