Proper way to hide status bar on iOS, with animati

Question

Consider a view controller that needs to slide out (or hide) the status bar when a button is clicked.

- (void) buttonClick:(id)sender
{
    [[UIApplication sharedApplication] setStatusBarHidden:YES
                                            withAnimation:UIStatusBarAnimationSlide];
}

The above effectively hides the status bar, but does not resize the root view appropriately, leaving a 20 pixel gap on top.

What I expected is the root view to expand over the space that was previously used by the status bar (animated, with the same duration than the status bar animation).

What's the proper way of doing this?

(I'm aware there are plenty of similar questions, but I couldn't find any about hiding the status bar on demand as opposed to hiding it to display a new view controller)

The "brute force" approach

Obviously, the following works...

[[UIApplication sharedApplication] setStatusBarHidden:YES
                                        withAnimation:UIStatusBarAnimationSlide];
[UIView animateWithDuration:0.25 animations:^{
    CGRect frame = self.view.frame;
    frame.origin.y -= 20;
    frame.size.height += 20;
    self.view.frame = frame;
}];

...but has disadvantages:

• Hardcodes the duration of the slide animation
• Hardcodes the height of the status bar
• The root view origin stays at (0,-20). I like my frames to start at (0,0) whenever possible.

What I already tried

• Made sure the autoresize mask of the root view has UIViewAutoresizingFlexibleTopMargin and UIViewAutoresizingFlexibleHeight.
• Called [self.view setNeedsLayout] after hiding the status bar.
• Called [self.view setNeedsDisplay] after hiding the status bar.
• Set wantsFullScreenLayout to YES before and after hiding the status bar.

Answer 1

Hide or Show status bar that also re-sizes the view:

-(void)statusBar:(BOOL)status {
UIViewController *rootViewController = self.view.window.rootViewController;
UIView *view = rootViewController.view;

// Hide/Unhide the status bar
[[UIApplication sharedApplication] setStatusBarHidden:status]; // BOOL : YES or NO

// statusBar frame
CGRect statusBarFrame = [UIApplication.sharedApplication statusBarFrame];
// Establish baseline frame
CGRect newViewFrame = self.view.window.bounds;

// Check statusBar frame is worth dodging
if (!CGRectEqualToRect(statusBarFrame, CGRectZero)) {
    UIInterfaceOrientation currentOrientation = rootViewController.interfaceOrientation;
    if (UIInterfaceOrientationIsPortrait(currentOrientation)) {
        // If portrait need to shrink height
        newViewFrame.size.height -= statusBarFrame.size.height;
        if (currentOrientation == UIInterfaceOrientationPortrait) {
            // If not upside-down move down origin
            newViewFrame.origin.y += statusBarFrame.size.height;
        }
    } else { // Is landscape 
        // portrait shrink width
        newViewFrame.size.width -= statusBarFrame.size.width;
        if (currentOrientation == UIInterfaceOrientationLandscapeLeft) {
            // If the status bar is on the left side of the window move origin
            newViewFrame.origin.x += statusBarFrame.size.width;
        }
    }
}
view.frame = newViewFrame; // pass new frame 
}

call method(message):

 if ([[UIApplication sharedApplication] isStatusBarHidden]) {
        [self statusBar:NO];
 } else {
        [self statusBar:YES];
 }