实现颜色渐变

第一种方法:

@property(nonatomic, assign)CGPoint inputPoint0;    //  这两个点事定义颜色渐变的区域@property(nonatomic, assign)CGPoint inputPoint1;@property(nonatomic, strong)UIColor *inputColor0;   //  这两种颜色定义起始到结束的颜色@property(nonatomic, strong)UIColor *inputColor1;_inputPoint0 = CGPointMake(0, 0);    _inputPoint1 = CGPointMake(1, 1);    _inputColor0 = [UIColor orangeColor];    _inputColor1 = [UIColor greenColor];    //   实现    CAGradientLayer *gradientLayer = [[CAGradientLayer alloc] init];    gradientLayer.colors = @[(__bridge id)_inputColor0.CGColor, (__bridge id)_inputColor1.CGColor];    gradientLayer.startPoint = _inputPoint0;    gradientLayer.endPoint = _inputPoint1;    gradientLayer.frame = self.view.bounds;    [self.view.layer addSublayer:gradientLayer];//  实现方式一//  在目标view使用masonry进行约束时, 为了使颜色渐变layer生效, 需要在viewController中加上- (void)viewDidLayoutSubviews {   //   在view的bounds改变时, 调整layer的大小    gradientLayer.frame = blockSelf.bottomLabel.bounds;        //左边为layer, 右边是目标view}//  实现方式二//  直接对view的layer进行操作_label = [[UILabel alloc] init];//    label.frame = CGRectMake(100, 100, 200, 300);    [self.view addSubview:_label];    _label.center = self.view.center;    _label.layer.borderWidth = 1;    [_label mas_makeConstraints:^(MASConstraintMaker *make) {        make.left.and.top.offset(50);        make.center.equalTo(self.view);    }];//    label.backgroundColor = [UIColor grayColor];    [self setupGradientLayer:(CAGradientLayer *)_label.layer];- (void)setupGradientLayer:(CAGradientLayer *)gradientLayer {//        _gradientLayer = [[CAGradientLayer alloc] init];        gradientLayer.colors = @[(__bridge id)[UIColor orangeColor].CGColor, (__bridge id)[UIColor purpleColor].CGColor, (__bridge id)[UIColor blueColor].CGColor, (__bridge id)[UIColor redColor].CGColor];        gradientLayer.locations = @[@(0), @(0.5), @(0.75), @(1)];        gradientLayer.startPoint = CGPointMake(0, 0);        gradientLayer.endPoint = CGPointMake(0, 1);}//  在label的extension中:#import "UILabel+Extension.h"@implementation UILabel (Extension)+ (Class)layerClass {    return [CAGradientLayer class];}@end

效果: