OC11_Block

main.m
#import <Foundation/Foundation.h>int main(int argc, const char * argv[]) {
1.函数指针 函数回调 动态排序Block   块语法本质     匿名函数类似     函数指针当做     变量使用四类Block
(1).无参数,无返回值.block1                   block变量void(^)(void)            block类型^void(void){函数体}       block初值(匿名函数)void(^block1)(void) = ^void(void) {NSLog(@“无参数,无返回值”);
};
block调用,类似函数调用.
block1();(2).有参数,无返回值.
参数1:字符串.
参数2:可变数组.
void(^block2)(NSString *, NSMutableArray *) = ^void(NSString *string, NSMutableArray *array) {[array addObject:string];NSLog(@"%@", array);
};
参数传入.
block2(@"Messi", [NSMutableArray array]);(3).无参数,有返回值.
block 初值可以不写返回值类型.(NSInteger可以不写)
NSInteger(^block3)(void) = ^NSInteger(void) {return 100L
}
NSLog(@"%ld", block());(4).有参数,有返回值.
NSMutableDictionary *(^block4)(NSString *, NSMutableArray *) = ^NSMutableDictionary *(NSString *string, NSMutableArray *array) {NSMutableDictionary *dic = [NSMutableDictionary dictionary];[dic setObject:array forKey:string];return dic;
}
NSLog(@"%@", block4(@"Messi", @[@"AA", @"BB"]));

*****注意*****
(1).等号后面的参数,类型和位置必须一致;等号后面的参数一定要有参数名.
(2).如果有返回值,返回值的类型必须一致.    return 0;
}

2.block和变量之间的关系.
NSInteger value = 100L;
void(^blockTest)(void) = ^void(void) {NSLog(@“%ld, %ld“, value, ++a);   // NSLog(“%ld, %@“, value, a); 如果在value前++, 会报错,value = 100L,这样后面就可以在value前++.或者在NSInteger前加static,static NSInteger value = 100L,这样后面就可以在value前++,或者将NSInteger value = 100L写在main之上.
}
blockTest();#import <Foundation/Foundation.h>
// 在main上方写变量了声明.
NSInteger *a = 123;int main(int argc, const char * argv[]) {

3.block重定义的使用.
#import <Foundation/Foundation.h>// block 重定义
typedef void(^BLOCK)(id);int main(int argc, const char * argv[]) {// block重定义的使用.BLOCK blockPrint = ^(id object) {NSLog(%@, object);
};
blockPrint(@[@"messi", @"kaka"]);
}

4.高级排序,block排序
main.m
(1).block排序器
NSArray *arr = @[@"meiss", @"kaka", @"ABC", @"GHJ"];
NSComparator blockCMP = ^(id obj1, id obj2) {// 升序return [obj1 compare:obj2];// 降序return -[obj1 compare:obj2];
};
NSArray *newArr = [arr sortedArrayUsingComparator:blockCMP];
blockPrint(newArr);

结合上面的block重定义的使用方法

(2).排序
NSArray *nnArray = [arr sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {return -[obj1 compare:obj2];
}];
blockPrint(nnArray);

(3).可变数组
NSMutableArray *mArr = [NSMutableArray arrayWithArray:arr];
[mArr sortUsingComparator:^NSComparisonResult(id obj1, id obj2) {return [obj1 compare:obj2];
}];
blockPrint(mArr);

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