ios-模拟imageView的类

.h文件

#import <UIKit/UIKit.h>@interface ImageView : UIView@property (nonatomic ,strong)UIImage * image;- (instancetype)initWithImage:(UIImage *)image;@end

.m文件

#import "ImageView.h"@implementation ImageView- (instancetype)initWithImage:(UIImage *)image{    self = [super initWithFrame:CGRectMake(0, 0, image.size.width, image.size.height)];//这里为什么要设置initWithFrame不直接init因为initWithImage会自动初始化一个frame，x和y为0，宽高为图片的宽高    if (self) {        self.image=image;    }    return self;}-(void)setImage:(UIImage *)image{    //先赋值    _image=image;    //重绘    [self setNeedsDisplay];}-(void)drawRect:(CGRect)rect{    //传过来的图片绘制到屏幕上    [self.image drawInRect:rect];}@end