jason-cooke/njkscrollfullscreen

Scroll to full screen like Facebook app

NJKScrollFullSrceen

NJKScrollFullSrceen is Facebook App like scroll to full screen library.

This repository consists of full screen delegate and full screen UI behaivior module.

• NJKScrollFullScreen
• Simple UIScrollViewDelegate wrapper. It called delegate methods when full screen wanted.
• UIViewController+NJKFullScreenSupport
• Add full screen behaivior to UIViewController.

These modules are individual. You can implement your own customized full screen behavior without UIViewController+NJKFullScreenSupport. NJKScrollFullSrceen can apply not only UIScrollView but also UIWebView and UITableView.

Requirements

• iOS 5.0 or later
• ARC

Install

CocoaPods

pod 'NJKScrollFullScreen'

Usage

1. Instance NJKScrollFullScreen

Instance and set UIScrollViewDelegate on your view controller. If you set scrollViewDelegate, NJKScrollFullScreen suould perform as a proxy object.

- (void)viewDidLoad
{
    [super viewDidLoad];

    _scrollProxy = [[NJKScrollFullScreen alloc] initWithForwardTarget:self]; // UIScrollViewDelegate and UITableViewDelegate methods proxy to ViewController
    self.tableView.delegate = (id)_scrollProxy; // cast for surpress incompatible warnings
    _scrollProxy.delegate = self;
}

2. Implement delegate methods

- (void)scrollFullScreen:(NJKScrollFullScreen *)proxy scrollViewDidScrollUp:(CGFloat)deltaY
{
    [self moveNavigationBar:deltaY animated:YES];
}

- (void)scrollFullScreen:(NJKScrollFullScreen *)proxy scrollViewDidScrollDown:(CGFloat)deltaY
{
    [self moveNavigationBar:deltaY animated:YES];
}

- (void)scrollFullScreenScrollViewDidEndDraggingScrollUp:(NJKScrollFullScreen *)proxy
{
    [self hideNavigationBar:YES];
}

- (void)scrollFullScreenScrollViewDidEndDraggingScrollDown:(NJKScrollFullScreen *)proxy
{
    [self showNavigationBar:YES];
}

3. Implement full screen behavior

You can choose UIViewController+NJKFullScreenSupport or your own view management code.

Use UIViewController+NJKFullScreenSupport.h.

#import "UIViewController+NJKFullScreenSupport.h"

Or you can implement own full screen behavior like below.

- (void)showNavigationBar:(BOOL)animated
{
    CGFloat statusBarHeight = [UIApplication sharedApplication].statusBarFrame.size.height;
    [self setNavigationBarOriginY:statusBarHeight animated:animated];
}

- (void)hideNavigationBar:(BOOL)animated
{
    [self setNavigationBarOriginY:0 animated:animated];
}

- (void)moveNavigationBar:(CGFloat)deltaY animated:(BOOL)animated
{
    CGRect frame = self.navigationController.navigationBar.frame;
    CGFloat nextY = frame.origin.y + deltaY;
    [self setNavigationBarOriginY:nextY animated:animated];
}

- (void)setNavigationBarOriginY:(CGFloat)y animated:(BOOL)animated
{
    CGFloat statusBarHeight = [UIApplication sharedApplication].statusBarFrame.size.height;
    CGRect frame = self.navigationController.navigationBar.frame;
    CGFloat navigationBarHeight = frame.size.height;

    frame.origin.y = fmin(fmax(y, navigationBarHeight), statusBarHeight); // limit over moving

    [UIView animateWithDuration:animated ? 0.1 : 0 animations:^{
        self.navigationController.navigationBar.frame = frame;
    }];
}

License

MIT license.