iOS 小知识点总结

• 子类实现父类方法时，监测子类是否调用super方法。

在父类中声明方法时：

- (void)functionWith:(NSArray*)arr1 string:(NSString*)string arr:(NSArray*)arr2NS_REQUIRES_SUPER;

子类中实现该父类方法：

- (void)functionWith:(NSArray *)arr1string:(NSString *)stringarr:(NSArray *)arr2 {//不调用super方法，报警告⚠️[superfunctionWith:nilstring:nilarr:nil];}   

• 图片压缩

func imageCompress(targetWidth:CGFloat) -> UIIMage {
   let targetHeight = targetWidth/width*height
   UIGraphicsBeginImageContext(CGSizeMake(targetWidth,targetHeight))
   self.drawInRect(CGRectMake(0,0,targetWidth,targetHeight))
   let newImage:UIImage = UIGraphicsGetImageFromCurrentImageContext()
            UIGrapicsEndImageContext()
   return newImage
}