四、Foundation框架

7_1_NSStringTest.m

#import <Foundation/Foundation.h>

int main(int argc, char const *argv[])
{
    @autoreleasepool
    {
        unichar data[6] = {97, 98, 99, 100, 101, 102};
        // 使用unicode数值数组初始化字符串
        NSString* str1 = [[NSString alloc] initWithCharacters: data length:6];
        NSLog(@"str1=%@", str1);

        // c风格的字符串
        char* cstr1 = "hello NSString";
        NSString* str2 = [NSString stringWithUTF8String: cstr1];
        NSLog(@"str2=%@", str2);

        // 将字符串写入文件
        [str2 writeToFile: @"myFile.txt" 
            atomically: YES 
            encoding: NSUTF8StringEncoding 
            error: nil];

        // 读取文件内容
        NSString* str3 = [NSString stringWithContentsOfFile: @"myFile.txt"
            encoding: NSUTF8StringEncoding
            error: nil];
        NSLog(@"str3=%@", str3);

        // 以下是常用方法
        NSString* str = @"hello ios,";
        NSString* book = @"《疯狂IOS讲义》";
        str = [str stringByAppendingFormat: @"%@是一本非常不错的图书", book];
        NSLog(@"afterstr1=%@", str);
        NSLog(@"str length1=%lu", [str length]);
        NSLog(@"str length2=%lu", [str lengthOfBytesUsingEncoding: NSUTF8StringEncoding]);
        NSLog(@"substr1=%@", [str substringToIndex: 10]);
        NSLog(@"substr2=%@", [str substringFromIndex: 2]);
        NSLog(@"substr3=%@", [str substringWithRange: NSMakeRange(1, 4)]);  
        NSRange pos = [str rangeOfString: @"o"];
        NSLog(@"substr4=%ld", pos.location);
        NSLog(@"substr5=%@", [str uppercaseString]);
        NSLog(@"substr6=%@", [str lowercaseString]);
    }
}

7_2_NSDateTest.m

#import <Foundation/Foundation.h>

int main(int argc, char const *argv[])
{
    @autoreleasepool
    {
        // 当前时间, 标准暁
        NSDate* date1 = [NSDate date];
        NSLog(@"date1=%@", date1);

        // 1天之后
        NSDate* date2 = [[NSDate alloc] initWithTimeIntervalSinceNow: 60 * 60* 24];
        NSLog(@"date2=%@", date2);

        // 1天前
        NSDate* date3 = [[NSDate alloc] initWithTimeIntervalSinceNow: -60 * 60* 24];
        NSLog(@"date3=%@", date3);

        // 1970之后
        NSDate* date4 = [NSDate dateWithTimeIntervalSince1970: 60 * 60* 24 * 365 * 20];
        NSLog(@"date4=%@", date4);

        // 当前时区
        NSLocale* cn = [NSLocale currentLocale];
        NSLog(@"当前时间的当前时区=%@", [date1 descriptionWithLocale: cn]);

        // 取小/大的时间
        NSDate* smallDate = [date1 earlierDate: date2];
        NSLog(@"smallDate=%@", smallDate);

        NSDate* bigDate = [date1 laterDate: date2];
        NSLog(@"bigDate=%@", bigDate);

        // 比较时间
        NSComparisonResult rslt = [date1 compare: date2];
        switch (rslt)
        {
            case NSOrderedAscending:
                NSLog(@"date1小于data2");
                break;
            case NSOrderedSame:
                NSLog(@"date1等于data2");
                break;
            case NSOrderedDescending:
                NSLog(@"date1小于data2");
                break;
        }

        // 时间差, 秒
        NSLog(@"date1与date2的时间差 = %g", [date1 timeIntervalSinceDate: date2]);
    }
}

7_3_NSObjCopy.m

#import <Foundation/Foundation.h>

int main(int argc, char const *argv[])
{
    @autoreleasepool
    {
        NSMutableString* book = [NSMutableString stringWithString: @"我是一本书"];
        NSMutableString* bookCopy = [book mutableCopy];
        [bookCopy replaceCharactersInRange:
         NSMakeRange(2,3)
         withString: @"Android"];
        NSLog(@"book的值为: %@", book);
        NSLog(@"bookCopy的值为: %@", bookCopy);
    }
}

7_5_NSArray.m

#import <Foundation/Foundation.h>

NSComparisonResult intSort(id num1, id num2, void *comtext)
{
    int v1 = [num1 intValue];
    int v2 = [num2 intValue];
    if (v1 < v2)
    {
        return NSOrderedAscending;
    }
    else if (v1 > v2)
    {
        return NSOrderedDescending;
    }
    else
    {
        return NSOrderedSame;
    }
}

int main(int argc, char const *argv[])
{
    @autoreleasepool
    {
        NSArray* array = [NSArray arrayWithObjects:
                          @"一a",
                          @"二b",
                          @"三c",
                          nil];
        NSLog(@"first item: %@", [array objectAtIndex: 0]);
        NSLog(@"secod item: %@", array[1]);
        NSLog(@"last  item: %@", [array lastObject]);
        
        // 获取从[1,2]的集合
        NSArray* arr1 = [array objectsAtIndexes:
                         [NSIndexSet
                          indexSetWithIndexesInRange:
                          NSMakeRange(1,2)]];
        NSLog(@"arr1 = %@", arr1);
        NSArray* arr2 = [array subarrayWithRange:
                         NSMakeRange(1,2)];
        NSLog(@"arr2 = %@", arr2);
        NSLog(@"b在数组中的位置 %ld", [array indexOfObject: @"二b"]);
        
        // 追加元素
        array = [array arrayByAddingObject: @"四d"];
        NSLog(@"array = %@", array);
        array = [array arrayByAddingObjectsFromArray: arr1];
        NSLog(@"array = %@", array);
        // 排序
        array = [array sortedArrayUsingSelector:
                 @selector(compare:)];
        NSLog(@"array排序 = %@", array);
        
        // 数字排序
        NSArray* numArr1 = @[
                             [NSNumber numberWithInt: 20],
                             [NSNumber numberWithInt: 1],
                             [NSNumber numberWithInt: -8],
                             [NSNumber numberWithInt: 9],
                            ];
        numArr1 = [numArr1 sortedArrayUsingFunction: intSort context: nil];
        NSLog(@"numArr1 = %@", numArr1);
        numArr1 = [numArr1 sortedArrayUsingComparator:
                   ^(id obj1, id obj2)
                   {
                       int v1 = [obj1 intValue];
                       int v2 = [obj2 intValue];
                       if (v1 < v2)
                       {
                           return NSOrderedDescending;
                       }
                       else if (v1 > v2)
                       {
                           return NSOrderedAscending;
                       }
                       else
                       {
                           return NSOrderedSame;
                       }
                   }];
        NSLog(@"numArr1 = %@", numArr1);
        
        // 遍历
        NSEnumerator* enum1 = [numArr1 objectEnumerator];
        id object1;
        while(object1 = [enum1 nextObject])
        {
            NSLog(@"%d", [object1 intValue]);
        }
        for(id object2 in numArr1)
        {
            NSLog(@"%d", [object2 intValue]);
        }
        
        /* 可变的数组 */
        NSMutableArray* marray1 = [NSMutableArray arrayWithObjects:
                                   @"A", nil];
        [marray1 addObject: @"C"];
        NSLog(@"marray1 = %@", marray1);
    }
}

myFile.txt

hello NSString