ECStretchableHeaderView

A multi-purpose header view that you can attach to a UITableView (or any UIScrollView), allowing you to maximize the scrolling content's screen real state by expanding and contracting the top header upon scrolling down or up, or by delegating the decision on when to do this through a another object.

Useful when such header isn't fully needed, but might have some buttons or some other interactive control that needs to remain visible.

Usage

	ECStretchableHeaderView *headerView;

    headerView = [[ECStretchableHeaderView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, CGRectGetWidth(self.tableView.frame), maxHeight)];

	// the header will expand up to 320 pixels tall when scrolling down
	headerView.maxHeight = 320.0f;

	// the header will shrink down to 100 pixels tall when scrolling up
    headerView.minHeight = 100.0f;

    // for demo purposes we programmatically create
    // a height constraint for the header view 
    // but more likely you will create it on Interface Builder 
    // and assign it to a private IBOutlet property

	NSLayoutConstraint *heightConstraint = [NSLayoutConstraint
                                                   constraintWithItem:headerView
                                                   attribute:NSLayoutAttributeHeight
                                                   relatedBy:NSLayoutRelationEqual
                                                      toItem:nil
                                                   attribute:NSLayoutAttributeNotAnAttribute
                                                  multiplier:1.0
                                                    constant:headerView.maxHeight]];

    [headerView addConstraint:heightConstraint];

    headerView.heightConstraint = heightConstraint;

    // put it at the top of your table vew
    [headerView attachToScrollView:self.tableView inset:0.0f];

Why do you need to set a height constraint?

Because ECStretchableHeaderView is made to be auto-layout friendly, in a way that you can design your header view on your Storyboard, and not let it get your interface builder be full of layout errors and warnings for missing constraints.

The height of the header view varies by modifying this constraint constant, as opposed to changing the view's frame.

The example project contains a ECStretchableHeaderView that is not created programatically, but instead created in Interface Builder.

License

This project is MIT licensed. Feel free to contribute :-)

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