修改UIView的默认Layer后,修改View的值会动态修改Layer的值
效果图:
如上图所示,当我们修改了一个UIView的子类中的Layer内置类型时(如上图中我们将CALayer直接替换成了CAGradientLayer类),会直接作用到其内置的Layer当中.
我们可以用这个特性将Layer封装到View当中,然后直接修改view就能达到我们想要实现的目的.
源码:
//
// AlphaView.h
// YXMWeather
//
// Created by XianMingYou on 15/2/20.
// Copyright (c) 2015年 XianMingYou. All rights reserved.
// #import <UIKit/UIKit.h> @interface AlphaView : UIView @property (nonatomic, strong) NSArray *colors;
@property (nonatomic, strong) NSArray *locations;
@property (nonatomic) CGPoint startPoint;
@property (nonatomic) CGPoint endPoint; - (void)alphaType; @end
//
// AlphaView.m
// YXMWeather
//
// Created by XianMingYou on 15/2/20.
// Copyright (c) 2015年 XianMingYou. All rights reserved.
// #import "AlphaView.h" @interface AlphaView () {
CAGradientLayer *_gradientLayer;
} @end @implementation AlphaView /**
* 修改当前view的backupLayer为CAGradientLayer
*
* @return CAGradientLayer类名字
*/
+ (Class)layerClass {
return [CAGradientLayer class];
} - (instancetype)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
_gradientLayer = (CAGradientLayer *)self.layer;
}
return self;
} - (void)alphaType {
self.colors = @[[UIColor clearColor], [UIColor blackColor], [UIColor clearColor]];
self.locations = @[@(0.25), @(0.5), @(0.75)];
self.startPoint = CGPointMake(, );
self.endPoint = CGPointMake(, );
} /**
* 重写setter,getter方法
*/
@synthesize colors = _colors;
- (void)setColors:(NSArray *)colors {
_colors = colors; // 将color转换成CGColor
NSMutableArray *cgColors = [NSMutableArray array];
for (UIColor *tmp in colors) {
id cgColor = (__bridge id)tmp.CGColor;
[cgColors addObject:cgColor];
} // 设置Colors
_gradientLayer.colors = cgColors;
}
- (NSArray *)colors {
return _colors;
} @synthesize locations = _locations;
- (void)setLocations:(NSArray *)locations {
_locations = locations;
_gradientLayer.locations = _locations;
}
- (NSArray *)locations {
return _locations;
} @synthesize startPoint = _startPoint;
- (void)setStartPoint:(CGPoint)startPoint {
_startPoint = startPoint;
_gradientLayer.startPoint = startPoint;
}
- (CGPoint)startPoint {
return _startPoint;
} @synthesize endPoint = _endPoint;
- (void)setEndPoint:(CGPoint)endPoint {
_endPoint = endPoint;
_gradientLayer.endPoint = endPoint;
}
- (CGPoint)endPoint {
return _endPoint;
} @end