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Drawing gradient on UIView not working with iOS 91个
我创建了一个新项目.我链接了QuartzCore.framework并导入了< QuartzCore / QuartzCore.h>在ViewController.m中.
我创建了一个新项目.我链接了QuartzCore.framework并导入了< QuartzCore / QuartzCore.h>在ViewController.m中.
这是代码.
- (void)viewDidLoad {
[super viewDidLoad];
NSLog(@"view height %f",self.view.frame.size.height); // returns 667 on iPhone 6
NSLog(@"view width %f",self.view.frame.size.width); // returns 375 on iPhone 6
NSLog(@"layers count %lu",self.view.layer.sublayers.count); // returns 2
// Gradient
UIColor *colorOne = [UIColor blueColor];
UIColor *colorTwo = [UIColor greenColor];
NSArray *colorArray = @[colorOne,colorTwo];
NSNumber *locationOne = [NSNumber numberWithFloat:0.0];
NSNumber *locationTwo = [NSNumber numberWithFloat:1.0];
NSArray *locationArray = @[locationOne,locationTwo];
CAGradientLayer *gradientLayer = [CAGradientLayer layer];
gradientLayer.frame = self.view.frame;
gradientLayer.colors = colorArray;
gradientLayer.locations = locationArray;
[self.view.layer insertSublayer:gradientLayer atIndex:0];
//[self.view.layer insertSublayer:gradientLayer above:[self.view.layer.sublayers firstObject]]; // didn't work either
NSLog(@"layers count %lu",self.view.layer.sublayers.count); //returns 3
}
我尝试将视图的背景颜色设置为clearColor,在viewDidAppear中调用它,但它们都没有工作.我真的不知道自己错过了什么.在任何帮助下谢谢.
解决方法
你的颜色数组应该是NSArray * colorArray = @ [(id)colorOne.CGColor,(id)colorTwo.CGColor] ;,因为colors数组需要CGColorRefs,而不是UIColors,令人讨厌 – 请参阅
the CGGradientLayer docs