Question

我有像这个图像的自定义视图，它可以工作（我在 drawRect 中设置的文字字体和文字颜色）

+ ******************* +

* text 01 IMAGE *

* text 02 _______ *

+ ******************* +

现在我想从Interface Builde设置字体和颜色，但是我收到错误：

IB Designables：无法呈现AvailableSeatView的实例：渲染视图的时间超过200毫秒。您的绘图代码可能会遇到性能下降的问题。

这是我的代码：

在AvailableSeatView.h中

#import <UIKit/UIKit.h>
IB_DESIGNABLE
@interface AvailableSeatView : UIView
@property (nonatomic) IBInspectable UIImage *image;
@property (nonatomic) IBInspectable NSInteger numberSeats;
@property (nonatomic) IBInspectable UIFont *numberSeatsFont;
@property (nonatomic) IBInspectable UIColor *numberSeatsColor;
@property (nonatomic) IBInspectable NSString *title;

在AvailableSeatView.m

中

@implementation AvailableSeatView
- (void)drawRect:(CGRect)rect {
    //UIImage
    CGRect myFrame = self.bounds;
    CGFloat yImage = myFrame.size.height/2 - self.image.size.height < 0 ? 0 : myFrame.size.height/2 - self.image.size.height;
    CGRect imageFrame = CGRectMake(myFrame.size.width/2, yImage, self.image.size.width, self.image.size.height);
    [self.image drawInRect:imageFrame];

    //UILabel number of seats
    [self drawString:[NSString stringWithFormat:@"%li", (long)self.numberSeats]
            withFont:self.numberSeatsFont
            andColor:self.numberSeatsColor
            aligment: NSTextAlignmentRight
              inRect:CGRectMake(0, yImage, imageFrame.origin.x, self.image.size.height)];

    //UILabel Title
    UIFont *titleFont = [UIFont systemFontOfSize:20];
    UIColor *titleColor = [UIColor redColor];
    [self drawString:self.title
            withFont:titleFont
            andColor:titleColor
            aligment: NSTextAlignmentCenter
              inRect:CGRectMake(0, myFrame.size.height/2, myFrame.size.width, myFrame.size.height/2)];
}

- (void) drawString: (NSString*) s
           withFont: (UIFont*) font
           andColor: (UIColor *)color
           aligment: (NSTextAlignment) alignment
             inRect: (CGRect) contextRect {

    CGFloat fontHeight = font.pointSize;
    CGRect textRect = CGRectMake(0, contextRect.origin.y, contextRect.size.width, fontHeight);
    NSMutableParagraphStyle* p = [NSMutableParagraphStyle new];
    p.alignment = alignment;
    [s drawInRect:textRect withAttributes:@{NSFontAttributeName: font,
                                            NSForegroundColorAttributeName: color,
                                            NSParagraphStyleAttributeName: p}];
}
@end

在谷歌搜索后，我发现这篇文章：IBDesignable View Rendering times out我尝试覆盖 initWithFrame ， initWithCoder ，但它仍无效。

Answer 1

基本上，使用DrawRect（）方法进行实时渲染是一个错误的概念。 Apple为此提供了一个单独的方法（用于实时渲染目的）“ - （void）prepareForInterfaceBuilder {}”。但是，在这种情况下，您无法从IB设置UIFont属性。但是你可以设置UIcolor。

Sample Project

IBDesignable View Rendering

1 个答案: