DRPLoadingSpinner

DRPLoadingSpinner is a neat little loading spinner. It's pretty configurable, so you can achieve a variety of effects. Check out src/DRPLoadingSpinner.h for all the configurable properties. Even though it's quite configurable, DRPLoadingSpinner is easy to get started with. Here's a snippet of creating one with default settings:

DRPLoadingSpinner *spinner = [[DRPLoadingSpinner alloc] init];
[self.view addSubview:spinner];
[spinner startAnimating];

Done! See? That was easy. You can even use DRPLoadingSpinner as a drop-in replacement for UIRefreshControl. Check out its sibling, DRPRefreshControl.

DRPRefreshControl *refreshControl = [[DRPRefreshControl alloc] init];
[refreshControl addToScrollView:self.scrollView target:self action:@selector(refreshTriggered:)];

Bam! Now you've got a snazzy refresh control in just a couple lines of code. Refresh controls can be added to UITableViewControllers and, in iOS 10, any UIScrollView or UIScrollView subclass. You can use either a callback block or a target-action to get notified that a refresh has been triggered.

Why not Swift?

Swift is not yet source-stable, which means that whenever an update to Swift is released, there is a risk that older Swift code won't compile. You shouldn't have to wait for me or someone else to update this library to a new Swift version in order to use it. The good news is, thanks to Swift-ObjC interop, DRPLoadingSpinner can be accessed easily from Swift code and will not break when new versions are released.

Installing

Installing couldn't be easier. Just install the Pod and away you go! If you're not the CocoaPods type, you can always just add the contents of the src directory to your project and get building!

pod install 'DRPLoadingSpinner'

Customizing

There are a handful of things you can customize on your loading spinner:

Color sequence: DRPLoadingSpinner has the opportunity to change color every time it goes around. You can define what colors appear and in which order. When the end of the sequence is reached, it loops back to the beginning.
- To define a single color, just set colorSequence to an array with just one color, like: loadingSpinner.colorSequence = @[ UIColor.grayColor ];

loadingSpinner.colorSequence = @[ UIColor.cyanColor, UIColor.magentaColor, UIColor.yellowColor, UIColor.blackColor ];

Background rail color: You can add a background rail to your spinner by setting a color here. This defaults to UIColor.clear, which effectively disables it.

loadingSpinner.backgroundRailColor = UIColor.lightGrayColor;

Line width: You can change the thickness of the line drawn when the spinner is spinning:

loadingSpinner.lineWidth = 3; // a pretty thick line.

Minimum and maximum arc length: As the spinner is spinning, it expands and contracts. You can define how long it gets as its longest and how short it gets at its shortest. This is measured in radians - don't forget the handy M_PI family of constants!

loadingSpinner.maximumArcLength = (2 * M_PI) - M_PI_4; // line will get as long as 7/8 the circumference of the circle
loadingSpinner.minimumArcLength = 0; // line will completely disappear at its shortest.

Rotation direction: Which direction the spinner should spin. Defaults to DRPRotationDirectionClockwise, but can also be set to DRPRotationDirectionCounterClockwise.

loadingSpinner.rotationDirection = DRPRotationDirectionCounterClockwise;

Rotation cycle duration: As the spinner is expanding and contracting, it also spins about its center. The rotation cycle duration is how long it would take to make a complete revolution if left interrupted. It's a CFTimeInterval, so it's measured in seconds!

loadingSpinner.rotationCycleDuration = 2; // a short and pretty noticeable rotation

Draw cycle duration: Draw cycle duration is the length of time taken up by any period of expansion or contraction of the line. Time taken by expansion and contraction are always equal. I find that it's quite pleasant to look at if rotationCycleDuration and drawCycleDuration are multiples of one another.

loadingSpinner.drawCycleDuration = 1;

Draw animation timing function: The draw animation timing function controls how quick or gradual the animation will appear. This is a standard CAMediaTimingFunction, so you can use anything you like, but check out DRPLoadingSpinnerTimingFunction for some presets.

loadingSpinner.drawTimingFunction = [DRPLoadingSpinnerTimingFunction sharpInOut];

Handy APIs

-startAnimating and -stopAnimating do exactly what their names suggest.
-isAnimating will tell you whether or not the spinner is currently animating. Nifty!

Contributing