Add UICollectionView to NavigationBar

问题:

I'm trying to add a UICollectionView as a SubView to my NavigationBar.

[self.navigationController.view addSubview:self.hotspotCollectionView];

It seems to work properly but covers the back button, see the screenshot attached. Is there anyway to indent the collectionView so that the back button is properly visible? Also is there a way to increase the height of the navigationbar so I can use bigger thumbnail pictures in my CollectionView?

I'm using XCode 7 and iOS9.

回答1:

I was able to achieve this simple example

by using a subclass of UINavigationBar and setting a collection view to the view controller's navigationItem.titleView

---

#import <UIKit/UIKit.h>

@interface NavigationBar : UINavigationBar

@end

---

#import "NavigationBar.h"

@implementation NavigationBar

- (CGSize)sizeThatFits:(CGSize)size
{
    return CGSizeMake(self.superview.bounds.size.width, 80);
}

-(void)setFrame:(CGRect)frame {
    CGRect f = frame;
    f.size.height = 80;
    [super setFrame:f];
}

@end

---

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController

@end

---

#import "ViewController.h"
#import "CollectionViewCell.h"

@interface ViewController ()<UICollectionViewDelegate, UICollectionViewDataSource>
@property (nonatomic, weak) UICollectionView *collectionView;
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    UICollectionViewFlowLayout *layout=[[UICollectionViewFlowLayout alloc] init];

    UICollectionView *collectionView = [[UICollectionView alloc] initWithFrame:CGRectMake(0, 0, 300, 80) collectionViewLayout:layout];
    collectionView.backgroundColor = [UIColor clearColor];
    self.navigationItem.titleView = collectionView;
    [collectionView registerClass:[CollectionViewCell class] forCellWithReuseIdentifier:@"cell"];
    collectionView.delegate = self;
    collectionView.dataSource = self;
}


-(NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
    return 1;
}

-(NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
    return 5;
}

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    CollectionViewCell *cell = (CollectionViewCell *)[collectionView dequeueReusableCellWithReuseIdentifier:@"cell" forIndexPath:indexPath];
    cell.backgroundColor = [UIColor orangeColor];
    return cell;
}
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath
{
    return CGSizeMake(50, 50);
}

@end

---

I set the custom NavigationBar in the Interface Builder

---

Disclaimer 1: I cannot promise that this is a future proof solution or will work in any case. I didn't test it with things like auto layout or rotation.

Disclaimer 2: I personally would implement any datasource/delegate independently from the view controller. For tableViews and collection views I use my self grown OFAPopulator.

---

Here is a example code: gitlab.com/vikingosegundo/collectionview-in-navigationbar/tree/… there are still some UI quirks in it. But probably that was to be expected. I guess Apple just did not consider us changing the height. Actually I never saw an app with a different height for it's nav bar. But the code answers your question. Give it more love and it may be useful for you.

回答2:

I think the best decision in this situation is to use custom UIView subclass that mimics UINavigationBar. And setNavigationBarHidden:YES animated:NO to corresponding UINavigationController.