Cocoa原理指南-学习和实践1

【bolg目标】

bolg仅仅针对<Cocoa原理指南>书中代码进行本地测试和文档学习，书中理论不进行摘要

个人觉得此书值得推荐阅读，从整体上学习Cocoa

【实践环境】
Mac 10.6
XCode4

【正文】
Pdf版

Cocoa整体纵览图，在书中页码：
Foundation
　　P15
　　P16
　　P17
Application Kit
　　P20
　　P21

/**************************************************/
下面分析下P27书中代码

#import <Foundation/Foundation.h>
int main (int argc, const char * argv[]) {
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    NSArray *args = [[NSProcessInfo processInfo] arguments];
    NSCountedSet *cset = [[NSCountedSet alloc] initWithArray:args];
    NSArray *sorted_args = [[cset allObjects]
                            sortedArrayUsingSelector:@selector(compare:)];
    NSEnumerator *enm = [sorted_args objectEnumerator];
    id word;
    while (word = [enm nextObject]) {
        printf("%s\n", [word UTF8String]);
    }
   
    [cset release];
    [pool release];
    return 0;
}

比对资料学习，如下
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NSProcessInfo

此类是对当前进程信息的访问

The NSProcessInfo class provides methods to access information about the current process. Each process has a single, shared NSProcessInfo object, known as process information

agent.

Getting the Process Information Agent
+ processInfo
Accessing Process Information
– arguments
– environment
– processIdentifier
– globallyUniqueString
– processName
– setProcessName:
Sudden Application Termination
– disableSuddenTermination
– enableSuddenTermination
Getting Host Information
– hostName
– operatingSystem
– operatingSystemName
– operatingSystemVersionString
Getting Computer Information
– physicalMemory
– processorCount
– activeProcessorCount
– systemUptime

关于上面罗列的，一目了然的明白这些方法的目的

本例使用processInfo和arguments

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NSCountedSet 继承NSMutableSet : NSSet : NSObject

The NSCountedSet class declares the programmatic interface to a mutable, unordered collection of indistinct objects. A counted set is also known as a bag.

在本例，此类用于统计重复输入对象，在后续的调整代码有这么一句输出
NSLog(@"%@,%lu" ,item ,[cset countForObject:item]);

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sortedArrayUsingSelector:属于NSArray类的，用于数组排序
@selector(compare:)，通过文档，发现其中compare:这个函数来自NSNumber类{?这个是现行理解}，其原型：
- (NSComparisonResult)compare:(NSNumber *)aNumber

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按照书中描述，
SimpleCocoaTool a z c a l q m z
a
c
l
m
q
z

实际在调试中发现出现数据类似
/Users/...../SimpleCocoaTool
a
c
l
m
q
z

比书中所写代码多一个行输出

至于为什么会这样，要么书中作者截获，要么Xcode版本问题
下面在XCode4下进行下面改进
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为了在调试中实践，最后结果类似书中类似输出，改进原有代码：
int main (int argc, const char * argv[]) {
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
   
    NSMutableArray *args = [[NSMutableArray alloc] initWithArray:[[NSProcessInfo processInfo] arguments]];//把NSArray换成NSMutableArray
   
    [args removeObjectAtIndex:0];//移出第一个参数
   
    NSCountedSet *cset = [[NSCountedSet alloc] initWithArray:args];
   
    for(id item in cset)
    {
        NSLog(@"%@,%lu" ,item ,[cset countForObject:item]);
    }
   
    NSArray *sorted_args = [[cset allObjects]
                            sortedArrayUsingSelector:@selector(compare:)];
    NSEnumerator *enm = [sorted_args objectEnumerator];
    id word;
    while (word = [enm nextObject]) {
        printf("%s\n", [word UTF8String]);
    }
   
    for(id item in sorted_args)
    {
        NSLog(@"for %@" ,item);
    }
   
    [cset release];
    [pool release];
   
    return 0;
}

现在测试

SimpleCocoaTool a z c a l q m z
a
c
l
m
q
z
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