Question

起初：没有CGRect不是空的（我在整个网站上搜索并了解了解决它的所有可能方法，但到目前为止我似乎没有成功）

RqButton.h

#import <UIKit/UIKit.h>

@interface RqButton : UIButton
@property (nonatomic) int c;
@property (nonatomic) float r;
@property (nonatomic) float g;
@property (nonatomic) CGRect frame;

- (id)initWithFrame:(CGRect)frame c:(int)c;
@end

RqButton.m

#import "RqButton.h"
#import <QuartzCore/QuartzCore.h>

@implementation RqButton

+ (RqButton *)buttonWithType:(UIButtonType)type
{return [super buttonWithType:UIButtonTypeCustom];}


- (id)initWithFrame:(CGRect)frame c:(int)c
{
    self = [super initWithFrame:frame];
    if (self)
    {   self.r=c%16;
        self.g=c/16;

        [self drawRect:frame];
    }
    return self;
}


- (void)drawRect:(CGRect)rect
{
    CGContextRef ctx = UIGraphicsGetCurrentContext();

    float width =  CGRectGetWidth(rect);
    float height =  CGRectGetHeight(rect);

    UIColor *borderColor = [UIColor colorWithRed:0.05f green:0.05f blue:0.05f alpha:1.00f];
    NSLog(@"%f",width);

    CGFloat BGLocations[2] = { 0.0, 1.0 };
    CGFloat BgComponents[8] = { self.r*0.33f, self.g*0.33f, 0.0f , 1.0,
        0.00, 0.00, 0.00, 1.0 };
    CGColorSpaceRef BgRGBColorspace = CGColorSpaceCreateDeviceRGB();
    CGGradientRef bgRadialGradient = CGGradientCreateWithColorComponents(BgRGBColorspace, BgComponents, BGLocations, 2);

    UIBezierPath *roundedRectanglePath = [UIBezierPath bezierPathWithRoundedRect: CGRectMake(0, 0, width, height) cornerRadius: 5];
    [roundedRectanglePath addClip];

    CGPoint startBg = CGPointMake (width*0.5, height*0.5);
    CGFloat endRadius= 32;

    CGContextDrawRadialGradient(ctx, bgRadialGradient, startBg, 0, startBg, endRadius, kCGGradientDrawsAfterEndLocation);
    CGColorSpaceRelease(BgRGBColorspace);
    CGGradientRelease(bgRadialGradient);

    [borderColor setStroke];
    roundedRectanglePath.lineWidth = 2;
    [roundedRectanglePath stroke];

}

@end

像这样调用类

int xz=  buttons[x][y].frame.origin.x;
        int yz=  buttons[x][y].frame.origin.y;

        buttons[x][y] = [[RqButton alloc] initWithFrame:CGRectMake(xz, yz, 30, 30) c:(int)51  ];
        [buttons[x][y] addTarget:self action:@selector(actionPick:) forControlEvents:UIControlEventTouchDown];
        buttons[x][y].tag = tag;

        [self.view addSubview:buttons[x][y]];

我不能忽略错误，因为我的应用程序完全冻结了一些时间。我需要做所有这些来自定义按钮的外观。通过.xib将类应用于Button非常合适。

此

Error>: CGContextAddPath: invalid context 0x0. This is a serious error. This application, or a library it uses, is using an invalid context

很多CG方法都会出现; CGContextDrawRadialGradient：clip; CGContextSetStrokeColorWithColor：CGContextSaveGState：CGContextSetLineWidth：[...]

提前多多感谢

Answer 1

你不能那样自己调用drawRect。操作系统在绘制时调用drawRect方法，并且只有在为类设置环境之后才调用。这就是崩溃的原因。如果你想尽快强制平局，请调用[self setNeedsDisplay]。

CGContextAddPath：无效的上下文0x0

1 个答案: