苹果屏幕尺寸，像素，分辨率原文文档介绍地址：
https://www.paintcodeapp.com/news/ultimate-guide-to-iphone-resolutions
Objective-C 中 block块 的使用
http://fuckingblocksyntax.com
As a local variable:
returnType (^blockName)(parameterTypes) = ^returnType(parameters) {...};
As a property:
@property (nonatomic, copy, nullability) returnType (^blockName)(parameterTypes);
As a method parameter:
- (void)someMethodThatTakesABlock:(returnType (^nullability)(parameterTypes))blockName;
As an argument to a method call:
[someObject someMethodThatTakesABlock:^returnType (parameters) {...}];
As a typedef:
typedef returnType (^TypeName)(parameterTypes);
TypeName blockName = ^returnType(parameters) {...};
