iOS UI效果之毛玻璃效果和渐变效果

@property(nullable, copy) NSArray *colors;

/* An optional array of NSNumber objects defining the location of each
 * gradient stop as a value in the range [0,1]. The values must be
 * monotonically increasing. If a nil array is given, the stops are
 * assumed to spread uniformly across the [0,1] range. When rendered,
 * the colors are mapped to the output colorspace before being
 * interpolated. Defaults to nil. Animatable. */

@property(nullable, copy) NSArray<NSNumber *> *locations;

/* The start and end points of the gradient when drawn into the layer's
 * coordinate space. The start point corresponds to the first gradient
 * stop, the end point to the last gradient stop. Both points are
 * defined in a unit coordinate space that is then mapped to the
 * layer's bounds rectangle when drawn. (I.e. [0,0] is the bottom-left
 * corner of the layer, [1,1] is the top-right corner.) The default values
 * are [.5,0] and [.5,1] respectively. Both are animatable. */

@property CGPoint startPoint;
@property CGPoint endPoint;

- (void)insertGradient {
    
    UIColor *colorRed = [UIColor redColor];
    
    UIColor *colorBlue = [UIColor blueColor];
    
    UIColor *colorGreen = [UIColor greenColor];
    
    NSArray *colors = [NSArray arrayWithObjects:(id)colorRed.CGColor, (id)colorBlue.CGColor, (id)colorGreen.CGColor, nil];
    
    NSNumber *locationR = [NSNumber numberWithFloat:0.0];
    
    NSNumber *locationB = [NSNumber numberWithFloat:0.35];
    
    NSNumber *locationG = [NSNumber numberWithFloat:1.0];
    
    NSArray *locations = [NSArray arrayWithObjects:locationR, locationB, locationG, nil];
    
    //crate gradient layer
    
    CAGradientLayer *headerLayer = [CAGradientLayer layer];
    
    headerLayer.colors = colors;
    
    headerLayer.locations = locations;
    
    headerLayer.startPoint = CGPointMake(0.5, 0.);
    
    headerLayer.endPoint = CGPointMake(1, 1);
    
    headerLayer.frame = CGRectMake(0, 100, self.view.frame.size.width, self.view.frame.size.width);
    
    [self.view.layer addSublayer:headerLayer];
    
}

@property (nonatomic, strong, readonly) UIView *contentView; // Do not add subviews directly to UIVisualEffectView, use this view instead.
@property (nonatomic, copy, nullable) UIVisualEffect *effect;

- (void)insertBlurView {
    
    UIBlurEffect *effect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight];
    
    UIVisualEffectView *blurView = [[UIVisualEffectView alloc] initWithEffect:effect];
    
    blurView.frame = self.view.bounds;
    
    [self.view addSubview:blurView];
}