iOS tips - PopoverView on iPhone

在iPad上的menu選單常常可以看到popover方式呈現的menu，但不知為何在iPhone上不能implement，不過iOS 8之後iPhone也可以透過別的方式實現了



主要就是透過下面這段code，最重要的就是把要顯示的viewcontroller的popoverPresentationController的相對屬性設定好就行了
http://stackoverflow.com/questions/25319179/uipopoverpresentationcontroller-on-ios-8-iphone

- (IBAction)btnSelectDatePressed:(id)sender
{
    UINavigationController *destNav = [[UINavigationController alloc] initWithRootViewController:dateVC];/*Here dateVC is controller you want to show in popover*/
    dateVC.preferredContentSize = CGSizeMake(280,200);
    destNav.modalPresentationStyle = UIModalPresentationPopover;
    _dateTimePopover8 = destNav.popoverPresentationController;
    _dateTimePopover8.delegate = self;
    _dateTimePopover8.sourceView = self.view;
     CGRect frame = [[sender valueForKey:@"view"] frame];
    frame.origin.y = frame.origin.y+20;
    _dateTimePopover8.sourceRect = frame;
    destNav.navigationBarHidden = YES;
    [self presentViewController:destNav animated:YES completion:nil];
}