ios - IOS - 使用 drawRect 方法在视图上设置背景颜色

Question

我对 IOS 很陌生；我通过drawRect方法做了一些渐变等，现在，如果我想实现它，我将它子类化到视图中。但我在想，有什么方法可以调用方法 drawRect 并让它从 ViewController 的子类中设置视图的背景？

布局是这样的：

背景颜色.h

#import <UIKit/UIKit.h>

@interface BackgroundColor : UIView

@end

背景颜色.m

#import "BackgroundColor"

@implementation BackgroundColor___Fuschia


- (void)drawRect:(CGRect)rect
{
...
}

@end

ViewControllerNav.h

#import <UIKit/UIKit.h>

@interface ViewControllerNav : UIViewController

@end

ViewControllerNav.m

@interface ViewControllerNav ()

@end

@implementation ViewControllerNav

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

我假设我必须导入 BackgroundColor 并初始化方法还是？

（PS：我的 drawRect 方法使用 CGRect frame = rect；所以我需要通过我假设的视图大小？）

任何帮助都是有价值的

Answer 1

To answer your original question, you never call drawRect: directly. You call

[self.view setNeedsDisplay];

and the system takes care of calling your drawRect: at the appropriate time.