animationWithKeyPath的值：

　 transform.scale = 比例轉換

    transform.scale.x = 闊的比例轉換

    transform.scale.y = 高的比例轉換

    transform.rotation.z = 平面圖的旋轉

    transform.translation.x

transform.translation.y

transform.translation.z

    opacity = 透明度

    margin

    zPosition

    backgroundColor    背景颜色

    cornerRadius    圆角

    borderWidth

    bounds

    contents

    contentsRect

    cornerRadius

    frame

    hidden

    mask

    masksToBounds

    opacity

    position

    shadowColor

    shadowOffset

    shadowOpacity

    shadowRadius

• Table of Contents

• Introduction
• Core Animation Basics
• Setting Up Layer Objects
• Animating Layer Content
• Building a Layer Hierarchy
• Advanced Animation Tricks
• Changing a Layer’s Default Behavior
• Improving Animation Performance
• Appendix A: Layer Style Property Animations
• Appendix B: Animatable Properties
• Appendix C: Key-Value Coding Extensions
• Revision History

Key-Value Coding Extensions

Core Animation extends the NSKeyValueCoding protocol as it pertains to the CAAnimation and CALayer classes. This extension adds default values for some keys, expands wrapping conventions, and adds key path support for CGPoint, CGRect, CGSize, andCATransform3D types.

Key-Value Coding Compliant Container Classes

The CAAnimation and CALayer classes are key-value coding compliant container classes, which means that you can set values for arbitrary keys. Even if the key someKey is not a declared property of the CALayer class, you can still set a value for it as follows:

[theLayer setValue:[NSNumber numberWithInteger:50] forKey:@"someKey"];

You can also retrieve the value for arbitrary keys like you would retrieve the value for other key paths. For example, to retrieve the value of the someKey path set previously, you would use the following code:

someKeyValue=[theLayer valueForKey:@"someKey"];

Default Value Support

Core Animation adds a convention to key value coding whereby a class can provide a default value for a key that has no set value. TheCAAnimation and CALayer classes support this convention using the defaultValueForKey: class method.

To provide a default value for a key, create a subclass of the desired class and override its defaultValueForKey: method. Your implementation of this method should examine the key parameter and return the appropriate default value. Listing C-1 shows a sample implementation of the defaultValueForKey: method for a layer object that provides a default value for the masksToBounds property.

Listing C-1  Example implementation of defaultValueForKey:

+ (id)defaultValueForKey:(NSString *)key

{

    if ([key isEqualToString:@"masksToBounds"])

         return [NSNumber numberWithBool:YES];

    return [super defaultValueForKey:key];

}

Wrapping Conventions

When the data for a key consists of a scalar value or C data structure, you must wrap that type in an object before assigning it to the layer. Similarly, when accessing that type, you must retrieve an object and then unwrap the appropriate values using the extensions to the appropriate class. Table C-1 lists the C types commonly used and the Objective-C class you use to wrap them.

Key Path Support for Structures

The CAAnimation and CALayer classes lets you access the fields of selected data structures using key paths. This feature is a convenient way to specify the field of a data structure that you want to animate. You can also use these conventions in conjunction with thesetValue:forKeyPath: and valueForKeyPath: methods to set and get those fields.

CATransform3D Key Paths

You can use the enhanced key path support to retrieve specific transformation values for a property that contains a CATransform3D data type. To specify the full key path for a layer’s transforms, you would use the string value transform or sublayerTransform followed by one of the field key paths in Table C-2. For example, to specify a rotation factor around the layer’s z axis, you would specify the key pathtransform.rotation.z.

The following example shows how you can modify a layer using the setValue:forKeyPath: method. The example sets the translation factor for the x axis to 10 points, causing the layer to shift by that amount along the indicated axis.

[myLayer setValue:[NSNumber numberWithFloat:10.0] forKeyPath:@"transform.translation.x"];

https://developer.apple.com/library/prerelease/ios/releasenotes/General/iOS80APIDiffs/frameworks/QuartzCore.html

https://developer.apple.com/library/ios/documentation/Cocoa/Conceptual/CoreAnimation_guide/Key-ValueCodingExtensions/Key-ValueCodingExtensions.html#//apple_ref/doc/uid/TP40004514-CH12-SW2