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IOS开发－ 用block实现回调

2024-07-09 18:33:30   224人阅读

在IOS开发中经常会用到回调的情况，下面介绍如何用block实现回调。

1 #import <Foundation/Foundation.h>2 3 @interface BLock : NSObject4 5 + (void)getBlock:(void (^)(NSString *))someblock;6 7 @end
BLock.h
 1 #import "BLock.h" 2 #import <Foundation/Foundation.h> 3  4 @implementation BLock 5  6 + (void)getBlock:(void (^)(NSString *))someblock 7 { 8     NSLog(@"we are in a getBLock function"); 9     someblock(@"BLOCK GO GO");10 }11 @end
BLock.m

上面有一个BLock类， 里面有个静态方法，通过someblock回调一个string 数据。

 1 #import <Foundation/Foundation.h> 2 #import "BLock.h" 3 int main(int argc, const char * argv[]) 4 { 5  6     @autoreleasepool { 7          8         [BLock getBlock:^(NSString *str){NSLog(@"%@",str);}]; 9     }10     return 0;11 }
main.m

通过回调回来的str参数 ，在main里面显示。

输出结果如下

2014-06-26 18:01:31.065 MyFirstApp[2430:303] we are in a getBLock function2014-06-26 18:01:31.066 MyFirstApp[2430:303] BLOCK GO GOProgram ended with exit code: 0

 

也可以将BLock.h和BLock.m的文件改写成如下：

1 #import <Foundation/Foundation.h>2 3 typedef  void (^ablock)(NSString *);//将block定义为新的类型4 5 @interface BLock : NSObject6 7 + (void)getBlock:(ablock)someblock;8 9 @end
BLock.h
 1 #import "BLock.h" 2 #import <Foundation/Foundation.h> 3  4  5 @implementation BLock 6  7 + (void)getBlock:(ablock)someblock 8 { 9     NSLog(@"we are in a getBLock function");10     someblock(@"BLOCK GO GO");11 }12 @end
BLock.m

 


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