1 前言

Block Objects 的對象可以內聯或編碼為獨立的代碼塊。 今天我們就來介紹一下其用法。

2 代碼實例
今天我們不用IOS框架來開發，直接用簡單的程序來開發，下面來介紹一下如何用Xcode建立一個簡單的程序

2.1 新建項目

2.2 選擇Type為Foundation

2.3 新建一個類，在裡面添加需要調用的相應方法

TestBlockObject.h

 

[plain]
#import <Foundation/Foundation.h>

@interface TestBlockObject : NSObject

//正常方法
- (NSInteger) subtract:(NSInteger)paramValue from:(NSInteger)paramFrom;
//調用Block Object
- (void) callIntToString;

- (void) doTheConversion;

- (void) doTheConversionExt;

- (void) doTheConversionExt2;
@end

#import <Foundation/Foundation.h>

@interface TestBlockObject : NSObject

//正常方法
- (NSInteger) subtract:(NSInteger)paramValue from:(NSInteger)paramFrom;
//調用Block Object
- (void) callIntToString;

- (void) doTheConversion;

- (void) doTheConversionExt;

- (void) doTheConversionExt2;
@end
TestBlockObject.m

 

[plain]
#import "TestBlockObject.h"

@implementation TestBlockObject

- (NSInteger) subtract:(NSInteger)paramValue from:(NSInteger)paramFrom{
return paramFrom - paramValue;
}

//Block Object
NSString* (^intToString)(NSUInteger) = ^(NSUInteger paramInteger){
NSString *result = [NSString stringWithFormat:@"%lu",(unsigned long)paramInteger];
return result;
};
- (void) callIntToString{
NSString *string = intToString(10);
NSLog(@"string = %@", string);
}
//typedef 這個 intToStringBlock Object 的簽名, 這個簽名會告訴 編譯器我們的 Block Object 會接受什麼參數:
//這個 typedef 告訴編譯器 Block Objects 接受一個整數參數並且返回一個被 IntToString Converter 命名的標 示符來展現的字符串。
typedef NSString* (^IntToStringConverter)(NSUInteger paramInteger);

- (NSString *) convertIntToString:(NSUInteger)paramInteger
usingBlockObject:(IntToStringConverter)paramBlockObject
{
return paramBlockObject(paramInteger);
}

- (void) doTheConversion{
NSString *result = [self convertIntToString:123 usingBlockObject:intToString];
NSLog(@"result = %@",result);
}

- (void) doTheConversionExt{
IntToStringConverter inlineConverter = ^(NSUInteger paramInteger){
NSString *result = [NSString stringWithFormat:@"%lu",(unsigned long)paramInteger];
return result;};
NSString *result = [self convertIntToString:123 usingBlockObject:inlineConverter];
NSLog(@"result = %@", result);
}
//內聯
- (void) doTheConversionExt2{
NSString *result =
[self convertIntToString:123 usingBlockObject:^NSString *(NSUInteger paramInteger)
{
NSString *result = [NSString stringWithFormat:@"%lu",(unsigned long)paramInteger];
return result;
}];
NSLog(@"result = %@", result);
}

#import "TestBlockObject.h"

@implementation TestBlockObject

- (NSInteger) subtract:(NSInteger)paramValue from:(NSInteger)paramFrom{
return paramFrom - paramValue;
}

//Block Object
NSString* (^intToString)(NSUInteger) = ^(NSUInteger paramInteger){
NSString *result = [NSString stringWithFormat:@"%lu",(unsigned long)paramInteger];
return result;
};
- (void) callIntToString{
NSString *string = intToString(10);
NSLog(@"string = %@", string);
}
//typedef 這個 intToStringBlock Object 的簽名, 這個簽名會告訴 編譯器我們的 Block Object 會接受什麼參數:
//這個 typedef 告訴編譯器 Block Objects 接受一個整數參數並且返回一個被 IntToString Converter 命名的標 示符來展現的字符串。
typedef NSString* (^IntToStringConverter)(NSUInteger paramInteger);

- (NSString *) convertIntToString:(NSUInteger)paramInteger
usingBlockObject:(IntToStringConverter)paramBlockObject
{
return paramBlockObject(paramInteger);
}

- (void) doTheConversion{
NSString *result = [self convertIntToString:123 usingBlockObject:intToString];
NSLog(@"result = %@",result);
}

- (void) doTheConversionExt{
IntToStringConverter inlineConverter = ^(NSUInteger paramInteger){
NSString *result = [NSString stringWithFormat:@"%lu",(unsigned long)paramInteger];
return result;};
NSString *result = [self convertIntToString:123 usingBlockObject:inlineConverter];
NSLog(@"result = %@", result);
}
//內聯
- (void) doTheConversionExt2{
NSString *result =
[self convertIntToString:123 usingBlockObject:^NSString *(NSUInteger paramInteger)
{
NSString *result = [NSString stringWithFormat:@"%lu",(unsigned long)paramInteger];
return result;
}];
NSLog(@"result = %@", result);
}
main.m

 

[plain]
int main(int argc, const char * argv[])
{

@autoreleasepool {

TestBlockObject *test = [[TestBlockObject alloc] init];
NSInteger i = [test subtract:10 from:20];
NSLog(@"Simple method [test subtract:10 from:20] result is====>%ld",(long)i);
NSLog(@"callingBlockObject");
[test callIntToString];
NSLog(@"usingBlockObject");
[test doTheConversion];
NSLog(@"doTheConversionExt=====>");
[test doTheConversionExt];
NSLog(@"doTheConversionExt2=====>");
[test doTheConversionExt2];
[test release];
//Block Object
NSInteger (^subtract)(NSInteger, NSInteger) = ^(NSInteger paramValue, NSInteger paramFrom){ return paramFrom - paramValue;
};
NSLog(@"Simple Block Object result is %lu",subtract(10,20));

}
return 0;

}

int main(int argc, const char * argv[])
{

@autoreleasepool {

TestBlockObject *test = [[TestBlockObject alloc] init];
NSInteger i = [test subtract:10 from:20];
NSLog(@"Simple method [test subtract:10 from:20] result is====>%ld",(long)i);
NSLog(@"callingBlockObject");
[test callIntToString];
NSLog(@"usingBlockObject");
[test doTheConversion];
NSLog(@"doTheConversionExt=====>");
[test doTheConversionExt];
NSLog(@"doTheConversionExt2=====>");
[test doTheConversionExt2];
[test release];
//Block Object
NSInteger (^subtract)(NSInteger, NSInteger) = ^(NSInteger paramValue, NSInteger paramFrom){ return paramFrom - paramValue;
};
NSLog(@"Simple Block Object result is %lu",subtract(10,20));

}
return 0;

}
運行後控制台結果

2013-05-09 17:35:45.335 TestBlockObject[1986:303] Simple method [test subtract:10 from:20] result is====>10

2013-05-09 17:35:45.337 TestBlockObject[1986:303] callingBlockObject

2013-05-09 17:35:45.338 TestBlockObject[1986:303] string = 10

2013-05-09 17:35:45.339 TestBlockObject[1986:303] usingBlockObject

2013-05-09 17:35:45.339 TestBlockObject[1986:303] result = 123

2013-05-09 17:35:45.340 TestBlockObject[1986:303] doTheConversionExt=====>

2013-05-09 17:35:45.340 TestBlockObject[1986:303] result = 123

2013-05-09 17:35:45.341 TestBlockObject[1986:303] doTheConversionExt2=====>

2013-05-09 17:35:45.341 TestBlockObject[1986:303] result = 123

2013-05-09 17:35:45.342 TestBlockObject[1986:303] Simple Block Object result is 10