如何在Objective-C中聲明一個Block？
接下來正文中出現(xiàn)詞語定義:
returnType: 返回類型鲤遥， NSInteger斋日、BOOL、int挠羔、...
blockName: block名稱井仰，自己定義
parameterTypes: 參數(shù)類型 ，NSInteger破加、BOOL糕档、int、...
parameters : 參數(shù)類型 +名 稱 拌喉，NSInteger index, BOOL flag ...
someObject : 對象速那，實例對象 、類對象尿背、self端仰、...
-
局部變量
returnType (^blockName)(parameterTypes) = ^returnType(parameters) {...};
NSInteger (^myblock)(BOOL) = ^NSInteger(BOOL flag) {
//code
if(flag) return 1
return 0;
};
-
屬性
@property (nonatomic, copy) returnType (^blockName)(parameters);
@property (nonatomic, copy) NSInteger (^myblock)(BOOL flag);
-
方法參數(shù)
-(void)someMethodWithBlock:(returnType(^)(parameters))blockName;
- (void)someMethodWithBlock:(NSInteger(^)(BOOL flag))myblock
{
//code
NSInteger index = myblock(YES);
//處理返回值 index
}
-
方法調(diào)用的參數(shù)
[someObject someMethodWithBlock:^returnType (parameters) {...}];
[self someMethodWithBlock:^NSInteger(BOOL flag) {
///code
if (flag) return 1;
return 0;
}];
-
C函數(shù)的參數(shù)：
voidSomeFunctionWithBlock(returnType(^blockName)(parameterTypes));void someMethodWichBlock(NSInteger(^myblock)(BOOL)){ //code NSInteger index = myblock(YES); //處理返回值 index }; -
typedef：
typedef returnType (^blockName)(parameters);
blockName aBlock = ^returnType(parameters) {...};
typedef NSInteger (Myblock)(BOOL flag);
//調(diào)用
Myblock block = ^NSInteger(BOOL flag){
//code
if(flag)return 1;
return 0;
};
