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IOS開發（57）之構建 Block Objects

編輯：IOS開發綜合

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;