浅谈OC对象初始化的三种姿势

序

早上看了位仁兄写了 ! 《Swift:让人眼前一亮的初始化方式》的文章 。什么？！初始化？Objective-C！好吧，吓哔哔~~~

一、普通程序猿
普通程序员使用最常见路人姿势等场。普普通通，纯属陆仁辈。

陆仁贾写法：

// view 1

UIView *v1 = [UIView alloc] initWithFrame:CGRectMake(0, 0, 200, 100)];
v1.backgroundColor = [UIColor whiteColor];

// view 2

UIView *v2 = [UIView alloc] initWithFrame:CGRectMake(0, 120, 200, 100)];
v2.backgroundColor = [UIColor whiteColor];

// add to view
[self.view addSubview:v1];
[self.view addSubview:v2];

撸人已写法：撸人已明显比陆仁贾聪明多了。使用大括号隔离，view1与view2相互独立，创建代码变量不会相互污染。

// view 1
{
    UIView *v1 = nil;
    UIView *v = [UIView alloc] initWithFrame:CGRectMake(0, 0, 200, 100)];
    v.backgroundColor = [UIColor whiteColor];
    
    v1 = v;

    [self.view addSubview:v1];
}

// view 2
{
    UIView *v2 = nil;
    UIView *v = [UIView alloc] initWithFrame:CGRectMake(0, 120, 200, 100)];
    v.backgroundColor = [UIColor whiteColor];
    
    v2 = v;

    [self.view addSubview:v2];
}

路人饼写法

// view 1
UIView *v1 = nil;
{
    UIView *v = [UIView alloc] initWithFrame:CGRectMake(0, 0, 200, 100)];
    v.backgroundColor = [UIColor whiteColor];
    v1 = v;
}

// view 2
UIView *v2 = nil;
{
    UIView *v = [UIView alloc] initWithFrame:CGRectMake(0, 120, 200, 100)];
    v.backgroundColor = [UIColor whiteColor];
    v2 = v;
}

[self.view addSubview:v1];
[self.view addSubview:v2];

二、文艺程序猿
文艺程序猿，使用教科书姿势登场。使用模板方法模式。使用block隔离初始化代码。

谢谢@ArthurK的指正。使用模板方法来进行对象初始化。

首先给NSObject增加扩展接口

// 扩展NSObject，增加Builder接口

@interface NSObject (Creator)
+ (instancetype)z0_create:(void(^)(id that))block;
- (instancetype)z0_create:(void(^)(id that))block;
@end

// 实现
@implementation NSObject (Creator)

+ (instancetype) z0_create:(void(^)(id))block {
    instancetype instance = [[self alloc] init];
    block(instance);
    return instance;
}

- (instancetype) z0_create:(void(^)(id))block {
    block(self);
    return self;
}

@end

使用。代码简洁工整。处处都是文艺范。

- (void) foo {
// 使用
// view 1
UIView *v1 = [UIView z0_create:^(UIView *that) {
    that.frame = CGRectMake(0, 0, 320, 200);
    that.background = [UIColor whiteColor];
}];

// view 2
UIView *v2 = [[UIView alloc] init];
[v2 z0_create:^(UIView *that) {
    that.frame = CGRectMake(0, 0, 320, 200);
    that.background = [UIColor whiteColor];
}];

// 添加到父视图
[self.view addSubview:v1];
[self.view addSubview:v2];
}

三、二逼程序猿
最后入场的是二逼程序猿。

！#！@#@%&……&%&#￥%！@#￥！@#￥!!!!! 这个是什么卵？
其实....我也不知道！>_<# 自行领悟。
黑科技?🙃呵呵~~ 我就是代码少，你吹啊~~

补充：

语法：https://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html#Statement-Exprs

- (void) foo {
// view 1
  UIView *v1 = ({
      UIView *v = [UIView alloc] init];
      v.frame = CGRectMake(0, 0, 320, 200);
      v.background = [UIColor whiteColor];
      v;
  });

  // view2
  UIView *v2 = ({
      UIView *v = [UIView alloc] init];
      v.frame = CGRectMake(0, 120, 320, 200);
      v.background = [UIColor blueColor];
      v;
  });

  [self.view addSubview:v1];
  [self.view addSubview:v2];
}

总结

总结个鬼，就几行代码。爱干啥，干啥去~~ 白了个掰！