ios 塊文法的本質

塊文法的本質是：函數指標

塊文法的回調是通過傳遞函數指標實現的。

貼圖貼碼為快：

主函數：

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#import <Foundation/Foundation.h>#import "HomeClass.h"int main(int argc, const char * argv[]){    @autoreleasepool {                HomeClass *home = [[HomeClass alloc] init];        [home method];            }    return 0;}

HomeClass類：

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#import <Foundation/Foundation.h>@interface HomeClass : NSObject- (void)method;- (void)aactin:(NSString *)string;@end

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////  HomeClass.m//  BlockDemo////  Created by hanjun on 13-3-14.//  Copyright (c) 2013年 CompanyOfHanJun. All rights reserved.//#import "HomeClass.h"#import "ToolClass.h"@implementation HomeClass- (void)aactin:(NSString *)string{    NSLog(@"%@",string);}- (void)method{    ToolClass *tool = [[ToolClass alloc] init];    [tool handleData:0 numberb:0 Function:^(int a, int b) {        NSLog(@"%d %d",a,b);    }];        [tool action:^NSString *(NSString * string) {        NSLog(@"callBack:%@",string);        return @"hanjun";    }];        }@end

ToolClass類

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#import <Foundation/Foundation.h>@interface ToolClass : NSObject-(void)handleData:(int)a numberb:(int)b Function:(void (^)(int a,int b))testFunction;- (void)presentViewCompletion:(void (^)(void))completion;- (void)action:(NSString *(^)(NSString *))string;- (void)aactin:(NSString *)string;@end

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////  ToolClass.m//  BlockDemo////  Created by hanjun on 13-3-14.//  Copyright (c) 2013年 CompanyOfHanJun. All rights reserved.//#import "ToolClass.h"@implementation ToolClass//塊值傳參，沒有傳回值-(void)handleData:(int)a numberb:(int)b Function:(void (^)(int a,int b))testFunction{    int aaa=5,bbb=10;        testFunction(aaa,bbb);}//塊不僅可以傳參，還可以有傳回值- (void)action:(NSString *(^)(NSString *))string{        NSString * backReturn = string(@"yhy");    NSLog(@"backReturn = %@",backReturn);}int (^oneFrom)(int) = ^(int anInt){    return anInt-1;};int (^completion)(int)=^(int a){    return a;};//int (^completion)(int)=^(int a1){//    return a1+5;//};int (^myBlock)(int)=^(int a1){    return a1;};@end