How to stick UIView to top of UIWindow on iOS 7 - ios

Question

I have a custom UIView which I want to stick to the top of the UIWindow even when interface orientation changes. Here is the my view in portrait orientation
The problem is that prior iOS 8 UIWindow coordinate system is not being changed with the orientation changes. So I need to make all the calculations by hand.
The first thing is to change the transform of the UIView, which I do using this method
-(CGFloat)angleForOrientation:(UIInterfaceOrientation)orientation
{
CGFloat angle;
switch (orientation) {
case UIInterfaceOrientationLandscapeLeft:
angle = -M_PI /2.0;
NSLog(#"UIInterfaceOrientationLandscapeLeft");
break;
case UIInterfaceOrientationLandscapeRight:
angle = M_PI /2.0;
NSLog(#"UIInterfaceOrientationLandscapeRight");
break;
case UIInterfaceOrientationPortraitUpsideDown:
angle = M_PI;
NSLog(#"UIInterfaceOrientationPortraitUpsideDown");
break;
default:
angle = 0;
NSLog(#"UIInterfaceOrientationPortrait");
break;
}
return angle;
}
The second thing is to somehow map actual coordinate systems to UIWindow coordinate system, which stays the same.
So how should I calculate the frame of the custom UIView that even when the user rotates the view to other orientations I will have the same sized UIView sticked to the top centre of the screen?
For instance this is how should the view look like in landscape
By the way this image is generated from iOS 8 version. For which I do the following
self.frame = CGRectMake(window.bounds.size/2-50, 0, 100, 100);
CGFloat angle = [self angleForOrientation:orientation];
self.transform = CGAffineTransformMakeRotation(angle);
I need to do something similar to iOS 7. How can I achieve this?
Thanks for help!

Answer 1

So Finally I figured out how to implement this.
I've created the following method to calculate the rect which will stick the view to top based on given bounds.
-(CGRect)getTopRectForBounds:(CGRect)bounds orientation:(UIInterfaceOrientation)orientation window:(UIWindow *)window
{
CGRect newRect;
CGFloat statusBarHeight = [self getStatusBarHeight];
CGSize screenSize = window.screen.bounds.size;
CGFloat sW = screenSize.width;
CGFloat sH = screenSize.height;
CGFloat W = rect.size.width;
CGFloat H = rect.size.height;
switch (orientation) {
case UIInterfaceOrientationLandscapeLeft:
newRect = CGRectMake(statusBarHeight, (sH-W)/2, H,W);
break;
case UIInterfaceOrientationLandscapeRight:
newRect = CGRectMake(sW-H-statusBarHeight, (sH-W)/2, H,W);
break;
case UIInterfaceOrientationPortraitUpsideDown:
newRect = CGRectMake((sW-W)/2, sH-H-statusBarHeight, W,H);
break;
default:
newRect = CGRectMake((sW-W)/2, statusBarHeight, W,H);
break;
}
return newRect;
}
Then I just change the frame whenever orientation changes.
So first I listen to Orientation changes
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(statusBarFrameOrOrientationChanged:) name:UIApplicationDidChangeStatusBarOrientationNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:#selector(statusBarFrameOrOrientationChanged:) name:UIApplicationDidChangeStatusBarFrameNotification object:nil];
Then in the orientation change event handler and change the transform and the frame. (see my question to see the method which handles the transforms)
CGRect bounds = CGRectMake(0, 0, 100, 100);
UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;
self.frame = [self getTopRectForBounds:bounds orientation:orientation window:self.window]
CGFloat angle = [self angleForOrientation:orientation];
self.transform = CGAffineTransformMakeRotation(angle);