开发随笔2023Q1

1. 将UIView转换为图片

//初始化并绘制UI
HeadImageView *view = [[HeadImageView alloc] initWithFrame:frame BackGroundColor:backGroundColor Text:text TextColor:textColor TextFontOfSize:size];

//转化成image
UIGraphicsBeginImageContext(view.bounds.size);
CGContextRef ctx = UIGraphicsGetCurrentContext();
[view.layer renderInContext:ctx];
UIImage* tImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return tImage;

2. 计算UILabel内容的实际高度、行数

CGSize textMaxSize = CGSizeMake(UILabel的指定宽度, MAXFLOAT);
NSDictionary *textAttrs = @{NSFontAttributeName : 字体大小};
CGFloat textH（UILabel内容的实际高度） = [UILabel的属性名 boundingRectWithSize:textMaxSize options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading attributes:textAttrs context:nil].size.height;

NSNumber *count（UILabel内容的行高） = @((textH) / _label.font.lineHeight);
NSLog(@"共 %td 行", [count integerValue]);

2. 成员变量和属性

以下两种定义变量的方式，是有明显区别的。具体体现在self. brandImageView 和 strongSelf->_brandImageView调用的时候，尤其是在异步block回调中，..->_brandImageView会产生崩溃。

/// 1.
@interface ActivitySlidStoreItemCell()

@property (nonatomic, strong) UIImageView *brandImageView;
@property (nonatomic, strong) UIImageView *bgImageView;

@end

/// 2.
@interface ActivitySlidStoreItemCell() {
    UIImageView *_bgImageView;
    UIImageView *_brandImageView;
}
@end