OC, oc Language

OC, oc Language
Overview

• Introduction

  • CAKeyframeAnimation is also called a key frame animation.
  • CAKeyframeAnimation is a subclass of the abstract class CAPropertyAnimation. It can be directly used.
  • Specify the animation attributes through the values and path attributes.

• Notes

  • If the path attribute is specified, the values attribute is ignored.
  • CABasicAnimation is equivalent to CAKeyframeAnimation with only two key frames.

Common attributes of Key Frame Animation

• Values (NSArray *)

  • Multiple key frame values
  • Similar to the fromValue and toValue values of CABasicAnimation

• Path (CGPathRef)

  • Animation execution path
  • You can draw a path by drawing

• KeyTimes (NSArray *)

  • Execution time of each key frame
  • NSNumber type
  • If this parameter is not specified, the duration of all key frames is equal to the animation duration.

• TimingFunctions (NSArray *)

  • Array of speed control functions

• CalculationMode (NSString *)

  • Specifies the animation attribute of the key frame.
  • If this value is specified, the keyTimes and timingFunctions attribute values are ignored.
  • Default Value: kCAAnimationLinear

• RotationMode (NSString *)

  • Specify the rotation mode. The default value is nil.

Example

• Implementation

  • Draw the besell curve by listening to the touch events of the UI control that executes the animation.
  • Create a Key Frame Animation and specify the keyPath attribute of the animation.
  • Use the beiser curve as the animation execution path.
  • Add an animation to a specified layer

• Implementation steps (subclass of custom UIView)

  • Save the besher path using the member attributes

  @property (nonatomic, strong) UIBezierPath *path;

  • Listen to the status of the touch event and draw the beser Curve

    • Start

    // Determine the start point-(void) touchesBegan :( NSSet *) touches withEvent :( UIEvent *) event {// obtain the current touch point UITouch * touch = [touches anyObject]; CGPoint curretnPoint = [touch locationInView: self]; // create path UIBezierPath * path = [UIBezierPath bezierPath]; [path moveToPoint: curretnPoint]; // save path self. path = path ;}

    • Mobile

    // Add a line-(void) touchesMoved :( NSSet *) touches withEvent :( UIEvent *) event {// obtain the current touch point UITouch * touch = [touches anyObject]; CGPoint currentPoint = [touch locationInView: self]; // Add a line [self. path addLineToPoint: currentPoint]; // redraw the curve and display it on the layer [self setNeedsDisplay];}

    • End (create an animation)

    -(Void) touchesEnded :( NSSet *) touches withEvent :( UIEvent *) event {// create an animation CAKeyframeAnimation * animation = [CAKeyframeAnimation animation]; // specify the attributes of the animation, animation. keyPath = @ "position"; // sets the animation execution path, animation. path = self. path. CGPath; // set the animation execution time to animation. duration = 1; // set the animation repetition rate to animation. repeatCount = MAXFLOAT; // Add the animation to the corresponding layer [[self. subviews firstObject] layer] addAnimation: animation forKey: nil];}

  • Show the path to the Layer

  // Draw the path-(void) drawRect :( CGRect) rect {[self. path stroke];}