Ios 为什么我的CAGradientLayer没有显示?
我需要知道我做错了什么。我真的复制并粘贴到我的代码和梯度没有显示这一点Ios 为什么我的CAGradientLayer没有显示?,ios,objective-c,core-graphics,core-animation,cagradientlayer,Ios,Objective C,Core Graphics,Core Animation,Cagradientlayer,我需要知道我做错了什么。我真的复制并粘贴到我的代码和梯度没有显示这一点 #import "ViewController.h" @interface ViewController () @end @implementation ViewController - (void)viewDidLoad { [super viewDidLoad]; UIView *gradient_view = [[UIView alloc]initWithFrame:self.view.bo
#import "ViewController.h"
@interface ViewController ()
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
UIView *gradient_view = [[UIView alloc]initWithFrame:self.view.bounds];
CAGradientLayer *gradient_layer = [CAGradientLayer layer];
[gradient_layer setFrame:gradient_view.bounds];
gradient_layer.startPoint = CGPointMake(0, 0);
gradient_layer.endPoint = CGPointMake(0, 1);
UIColor *top_color = [UIColor redColor];
UIColor *bottom_color = [UIColor blueColor];
[gradient_layer setColors:@[top_color,bottom_color]];
[gradient_view.layer addSublayer:gradient_layer];
[self.view addSubview:gradient_view];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end
它只显示一个白色屏幕。谁能帮我弄清楚问题是什么。因为它现在真的很烦我。你可能会踢自己:) 渐变层需要CGColorRef,而不是UIColor:
CGColorRef topRef = [UIColor redColor].CGColor;
CGColorRef botRef = [UIColor blueColor].CGColor;
[gradient_layer setColors:@[(__bridge id)topRef, (__bridge id)botRef]];