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项目介绍：
block的5种基本用法的总结；适合初学者
As a local variable
As a property:
As a method parameter:
As an argument to a method call:
As a typedef:demo写的很low，希望大家好的建议
[Objective-C] 查看源文件 复制代码
控制器一
#import "ViewController.h"
#import "SecondViewController.h"
@interface ViewController ()
@property (nonatomic,copy) int (^FirstBlock)(int ,int);
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.FirstBlock = ^int(int a,int b){
return a + b;
};
}
/*
* 1.作为本地变量
As a local variable:
returnType (^blockName)(parameterTypes) = ^returnType(parameters) {...};
*/
- (IBAction)localVariable:(id)sender{
__block int sum ;
int (^myBlock)(int,int) = ^int(int a ,int b){
sum = a +b;
return sum;
};
NSLog(@"这是作为本地变量的----%d",myBlock(1,2));
}
/*
* 2. As a property:
@property (nonatomic, copy, nullability) returnType (^blockName)(parameterTypes);
*/
- (IBAction)asAproperty:(id)sender {
NSLog(@"这是作为属性的----%d",self.FirstBlock(2,3));
}
/*
* 3.作为方法参数
As a method parameter:
*/
- (IBAction)Asmethodparameter:(id)sender {
NSLog(@"作为方法参数被调用----%d",[self testMethodwithBlock:^int(int a, int b) {
NSLog(@"http://fuckingblocksyntax.com/ a = %d,b = %d",a,b);
return a * b -b;
}]);
}
/*4.作为方法传递
*As an argument to a method call:
*/
- (int)testMethodwithBlock:(int(^)(int a,int b))MehtodBlock{
//这个可能是传过来的参数
__block int i = 10;
int sum = 0;
if (MehtodBlock) {
sum = MehtodBlock(i,2*i);
}
return sum;
}
- (IBAction)presentSecondVC:(id)sender {
SecondViewController *secondVC = [[SecondViewController alloc]init];
secondVC.block = ^(id acolor){
self.view.backgroundColor = acolor;
};
UINavigationController *nav = [[UINavigationController alloc]initWithRootViewController:secondVC];
[self presentViewController:nav animated:YES completion:nil];
}
控制器二
#import "SecondViewController.h"
@interface SecondViewController ()
@end
@implementation SecondViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.title = @"这是第二个页面";
}
- (IBAction)gotoFirstVC:(id)sender {
if (self.block) {
self.block([UIColor redColor]);
}
[self dismissViewControllerAnimated:YES completion:nil];
}
testBlock.zip
(66.95 KB, 下载次数: 322)
2016-8-29 23:47 上传
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block的5种使用
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