pod 'PopoverObjC'
#import "ASViewController.h"
#import <PopoverObjC/ASPopover.h>
@interface ASViewController ()
@property (weak, nonatomic) IBOutlet UIButton *btn;
@property (nonatomic, strong) ASPopover *btnPopover;
@property (nonatomic, strong) ASPopover *itemPopover;
@end
@implementation ASViewController
- (void)viewDidLoad {
 [super viewDidLoad];
 [self.btn addTarget:self action:@selector(clickBtn:) forControlEvents:UIControlEventTouchUpInside];
 self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"item" style:UIBarButtonItemStylePlain target:self action:@selector(clickItem:)];
}
- (void)didReceiveMemoryWarning {
}

- (ASPopover *)btnPopover {
 if (!_btnPopover) {
 ASPopoverOption *option = [[ASPopoverOption alloc] init];
 option.popoverType = ASPopoverTypeUp;
 option.autoAjustDirection = NO;
 option.arrowSize = CGSizeMake(9, 6);
 option.blackOverlayColor = [UIColor clearColor];
 option.popoverColor = [UIColor lightGrayColor];
 option.dismissOnBlackOverlayTap = YES;
 option.animationIn = 0.5;
 //...
 _btnPopover = [[ASPopover alloc] initWithOption:option];
 }
 return _btnPopover;
}
- (ASPopover *)itemPopover {
 if (!_itemPopover) {
 ASPopoverOption *option = [[ASPopoverOption alloc] init];
 option.autoAjustDirection = NO;
 option.arrowSize = CGSizeMake(10, 6);
 option.blackOverlayColor = [UIColor clearColor];
 option.sideEdge = 7;
 option.dismissOnBlackOverlayTap = YES;
 option.popoverColor = [[UIColor blackColor] colorWithAlphaComponent:0.7];
 option.autoAjustDirection = YES;
 option.animationIn = 0.4;
 option.springDamping = 0.5;
 option.initialSpringVelocity = 1;
 option.overlayBlur = [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight];
 //...
 _itemPopover = [[ASPopover alloc] initWithOption:option];
 }
 return _itemPopover;
}

- (void)clickBtn:(id)sender {
 UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width - 50, 40)];
 [self.btnPopover show:view fromView:self.btn]; // in delegate window
}
- (void)clickItem:(id)sender {
 UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 100, 200)];
 UIView *itemView = [self.navigationItem.rightBarButtonItem valueForKey:@"view"]; // you should use custom view in item;
 if (itemView) {
// [self.itemPopover show:view fromView:itemView];
 CGPoint originPoint = [self.itemPopover originArrowPointWithView:view fromView:itemView];
 originPoint.y += 5;
 [self.itemPopover show:view atPoint:originPoint];
 }
}
@end

Popover interface
#import <UIKit/UIKit.h>
#import "ASPopoverOption.h"
typedef void (^ASPopoverBlock)(void);
@interface ASPopover : UIView
@property (nonatomic, copy) ASPopoverBlock willShowHandler;
@property (nonatomic, copy) ASPopoverBlock willDismissHandler;
@property (nonatomic, copy) ASPopoverBlock didShowHandler;
@property (nonatomic, copy) ASPopoverBlock didDismissHandler;
@property (nonatomic, strong) ASPopoverOption *option;
- (instancetype)initWithOption:(ASPopoverOption *)option;
- (void)dismiss;
- (void)show:(UIView *)contentView fromView:(UIView *)fromView;
- (void)show:(UIView *)contentView fromView:(UIView *)fromView inView:(UIView *)inView;
- (void)show:(UIView *)contentView atPoint:(CGPoint)point;
- (void)show:(UIView *)contentView atPoint:(CGPoint)point inView:(UIView *)inView;
- (CGPoint)originArrowPointWithView:(UIView *)contentView fromView:(UIView *)fromView;
- (CGPoint)arrowPointWithView:(UIView *)contentView fromView:(UIView *)fromView inView:(UIView *)inView popoverType:(ASPopoverType)type;
@end

PopoverOption Interface
typedef NS_ENUM(NSInteger, ASPopoverType) {
 ASPopoverTypeUp = 0,
 ASPopoverTypeDown,
};
@interface ASPopoverOption : NSObject
@property (nonatomic, assign) CGSize arrowSize;
@property (nonatomic, assign) NSTimeInterval animationIn; // if 0, no animation
@property (nonatomic, assign) NSTimeInterval animationOut;
@property (nonatomic, assign) CGFloat cornerRadius;
@property (nonatomic, assign) CGFloat sideEdge;
@property (nonatomic, strong) UIColor *blackOverlayColor;
@property (nonatomic, strong) UIBlurEffect *overlayBlur;
@property (nonatomic, strong) UIColor *popoverColor;
@property (nonatomic, assign) BOOL dismissOnBlackOverlayTap;
@property (nonatomic, assign) BOOL showBlackOverlay;
@property (nonatomic, assign) CGFloat springDamping;
@property (nonatomic, assign) CGFloat initialSpringVelocity;
@property (nonatomic, assign) ASPopoverType popoverType;
@property (nonatomic, assign) BOOL highlightFromView;
@property (nonatomic, assign) CGFloat highlightCornerRadius;
@property (nonatomic, assign) BOOL autoAjustDirection; // down preferred, effect just in view not at point
@end