黑马程序员_ Objective-c 之Foundation笔记(一)

时间:2021-05-15 16:17:29

结构体

 NSRange:

用来表示范围

创建

NSRange r1 = {2, 4}

NSRange r2 = {.location = 2, .length = 4}

NSRange r3 = NSMakeRange(2, 4)

查找某个字符串在str中的范围

NSString *str = @"i love oc";

NSRange range = [str rangeOfString:@"java"]

NSLog(@"location = %ld, length=%ld", range.location, range.length)

如果找不到,length=0,location=NSNotFound==-1

NSPoint:

用来表示一个点的坐标

创建

CGPoint p1 = NSMakePoint(10, 10);

NSPoint p2 = CGPointMake(20, 20);

表示原点

CGPointZero == CGPointMake(0, 0)

NSSize:

表示二维平面的尺寸

NSSize s1 = CGSizeMake(100, 50);

NSSize s2 = NSMakeSize(100, 50);

CGSize s3 = NSMakeSize(200, 60);

CGRect:

表示二维平面具体的一个尺寸和位置

CGRect r1 = CGRectMake(0, 0, 100, 50);

CGRect r2 = { {0, 0}, {100, 90}};

CGRect r3 = {p1, s2};

定义CGRect的另外方法

CGRect myRect(CGFloat x, CGFloat y, CGFloat width, CGFloat height)

{

CGRect rect;

rect.origin.x = x;

rect.origin.y = y;

rect.size.width = width;

rect.size.height = height;

}

将结构体转为字符串

NSString *str = NSStringFromPoint(p1);

NSString *str = NSStringFromSize(s3);

NSString *str = NSStringFromRect(r1);

比较两个点是否相同(x、y)

BOOL b = CGPointEqualToPoint(CGPointMake(10, 10), CGPointMake(10, 10))

判断一个点是否在某个区域

BOOL b2 = CGRectContainsPoint(CGRectMake(50, 40, 100, 50), CGPointMake(60, 45))

使用这些CGPointEqualToPoint、CGRectContainsPoint等函数的前提是添加CoreGraphics框架

NSString

字符串的创建

NSString *s1 = @"jack";

NSString *s2 = [[NSString alloc] initWithString:@"jack"];

NSString *s3 = [[NSString alloc] initWithFormat:@"age is %d", 10];

C字符串 > C字符串

const char *c = [s4 UTF8String];

NSUTF8StringEncoding 用到中文就可以用这种编码

NSString *s5 = [[NSString alloc] initWithContentsOfFile:@"/Users/apple/Desktop/1.txt" encoding:NSUTF8StringEncoding error:nil];

字符串的导出

NSString *str = @"4234234";

NSURL *url = [NSURL fileURLWithPath:@"/Users/apple/Desktop/my2.txt"];

[str writeToURL:url atomically:YES encoding:NSUTF8StringEncoding error:nil];

或者

[@"Jack\nJack" writeToFile:@"/Users/apple/Desktop/my.txt" atomically:YES encoding:NSUTF8StringEncoding error:nil]

NSMutableString

可变字符串

NSMutableString *s1 = [NSMutableString stringWithFormat:@"my age is 10"];

拼接内容到s1的后面

[s1 appendString:@" 11 12"];

获取is的范围

NSRange range = [s1 rangeOfString:@"is"];

删除is

[s1 deleteCharactersInRange:range];

不可变字符串也可以将两个字符串拼接

NSString *s2 = [NSString stringWithFormat:@"age is 10"];

NSString *s3 = [s2 stringByAppendingString:@" 11 12"];

补充知识:NSURL

file://   本地资源协议头

http://   网络资源协议头

创建一个资源路径

NSURL *url = [[NSURL alloc] initWithString:@"file:///Users/apple/Desktop/1.txt"]  本地资源

NSURL *url = [NSURL fileURLWithPath:@"/Users/apple/Desktop/1.txt"]  本地资源

将资源路径转化为字符串

NSString *s6 = [[NSString alloc] initWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil]