block的使用

#import <Foundation/Foundation.h>
@class EOCBlock;
//枚举block
typedef void (^TypedefBlock)(int param1, int param2);

@interface EOCBlock : NSObject

//声明block属性
@property (nonatomic, copy)int (^oneParamBlock)(int param);
@property (nonatomic, copy)void (^twoParamBlock)(int param1, int param2);
@property (nonatomic, copy)int (^noParamBlock)(void);
@property (nonatomic, assign)int result;

-(void)doT;
//block作为入参
-(void)doTBlock:(void(^)(int param1, int param2))twoParamBlock;
//block作为出参
-(void(^)(int param1, int param2))doGetBlock;
//block作为出参的应用
-(EOCBlock *(^)(int param))doContinueBlock;
@end

#import "EOCBlock.h"

@implementation EOCBlock

-(void)doT{
    int v = self.oneParamBlock(5);
    NSLog(@"xxx:%d",v);
}

-(void)doTBlock:(void (^)(int, int))twoParamBlock
{
    twoParamBlock(1,2);
    NSLog(@"doTBlock");
}

-(void (^)(int, int))doGetBlock
{
    return ^(int p1,int p2){
        NSLog(@"doGetBlock : %d",p1);
    };
}


-(EOCBlock *(^)(int))doContinueBlock
{
    return ^EOCBlock *(int p){
        _result *= p;
        return self;
    };
}

@end

- (void)viewDidLoad {
    [super viewDidLoad];
    
    __block int mult = 2;
    
    EOCBlock *e = [[EOCBlock alloc] init];
    e.oneParamBlock = ^int(int param) {
        //如果想要在block修改外部的变量，外部的变量需要用static、全局、__block
        mult = 3;
        return param * mult;
    };
    //必须先初始化block，再输出
    [e doT];
    
    NSLog(@"%@",e.oneParamBlock);
    
    //block作为入参
    [e doTBlock:^(int param1, int param2) {
        NSLog(@"param1:%d",param1);
    }];
    
    //block作为出参
    void (^block)(int,int) = [e doGetBlock];
    block(1,2);
    
    //block出参应用
    e.result = 1;
    e.doContinueBlock(1).doContinueBlock(2).doContinueBlock(3);
    NSLog(@"result:%d",e.result);
}