今天学习主要是学习分类，字符串，可变的字符串，number
一、分类：给现有的类添加方法，就是添加一个类，再添加一个类+方法名
在类+方法名的.h头文件里，
引入一个类的
#import "Dad.h"
@interface Dad(smoke)
-(void)smoke;
然后在Viewcontroller.M就可以调用smoke的方法了
二、字符串
（一）创建字符串
NSString *z1 =@"zbc";
// 用工厂方法创建字符串
NSString *z2 =[NSString stringWithFormat:@"李四"];
（二）字符串的截取
例：
NSString *string = @"http://www.baidu.com";
1、从头开始到第几个
NSString *substring1 = [string substringToIndex:7 ];
2、从第几个后开始到结束
NSString *substring2 = [string substringFromIndex:7];
3、截取范围
NSString *substring3 = [string substringWithRange:NSMakeRange(11, 5)];
//11是从第几个后开始，5是长度，几个
（三）字符串的拼接
NSString *s1 = @"名字是";
NSString *s2 = @"刘德华";
1、两个字符串连在一起
NSString *s3 = [NSString stringWithFormat:@"%@%@",s1,s2];
2、把一个字符串连在另个的后面
NSString *s4 = [s1 stringByAppendingString:s2];
3、前两个的结合版
NSString *s5 = [s1 stringByAppendingFormat:@":%@",s2];
4、path是指路径
NSString *desktopPath =@"/Users/lanyi/Desktop";
NSString *fileName = @"小电影.mp4";
NSString *filePath = [desktopPath stringByAppendingPathComponent:fileName];
NSLog(@"%@",filePath);
（三）字符串的替换
NSString *newPath = [filePath stringByReplacingOccurrencesOfString:@"/" withString:@"-"];
NSString *newName = [fileName stringByReplacingCharactersInRange:NSMakeRange(0, 1) withString:@"大"];
（四）判断字符串是否包含
if ([filePath rangeOfString:@"lanyi"].length>0) {
NSLog(@"包含");
}else NSLog(@"不包含");
（五）字符串编解码
1、把纯文本文件中的字符串 加载到内存中
NSString *path = @"/蓝懿二期/正式基础课/Day 8/饿了么.rtf";
NSString *abcString = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
2、把内存中的字符串保存到纯文本文件中
NSString *s = @"饿死我了 中午吃啥？？？？？";
s = [abcString stringByAppendingString:s];
[s writeToFile:path atomically:YES encoding:NSUTF8StringEncoding error:nil];
三、可变字符串：首先要创建好一个类，并且要添加好属性，然后在Viewcontroller.M就可以编写代码
//纯文本的路径保存到path
NSString*path = @"/Users/yeqian/Desktop/明星.txt";
//文件的路径装进字符串starsString里
NSString *starsString =[NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
//用数组裁成每一行并存到Lins
NSArray *lines = [starsString componentsSeparatedByString:@" "];
//准备一个可变的数组stars把所有的明星对象保存下来
NSMutableArray*stars = [NSMutableArray array];
//遍历lines并分割lines的字符串
for (NSString*line in lines) {
//用数组每一行裁成单个并存到dan
NSArray *dan = [line componentsSeparatedByString:@" "];
Star *s = [[Star alloc]init];
//用数组给对象s相应属性赋值
s.name = dan[0];
s.nationality =dan[1];
s.occupation = dan[2];
s.age = [dan[3] intValue] ;
//把对象S存入可变的数组stars
[stars addObject:s];
}
for (Star*s in stars) {
NSLog(@"%@ %@ %@ %d",s.name,s.nationality,s.occupation,s.age);
}
for (int i = 0; i<stars.count; i++) {
// 可变的数组stars相应属性 赋值给创建一个对象h
Star *h = stars[i];
UILabel *nameLabel = [[UILabel alloc]initWithFrame:CGRectMake(0, i*40+20, 80, 40)];
nameLabel.text =h.name;
nameLabel.textColor = [UIColor blackColor];
[self.view addSubview:nameLabel];
UILabel *nationalityLabel = [[UILabel alloc]initWithFrame:CGRectMake(80, i*40+20, 80, 40)];
nationalityLabel.text =h.nationality;
nationalityLabel.textColor = [UIColor blackColor];
[self.view addSubview:nationalityLabel];
UILabel *occupationLabel = [[UILabel alloc]initWithFrame:CGRectMake(160, i*40+20, 80, 40)];
occupationLabel.text =h.occupation;
occupationLabel.textColor = [UIColor blackColor];
[self.view addSubview:occupationLabel];
UILabel *ageLabel = [[UILabel alloc]initWithFrame:CGRectMake(240, i*40+20, 80, 40)];
ageLabel.text =[@(h.age) stringValue];
ageLabel.textColor = [UIColor blackColor];
[self.view addSubview:ageLabel];
}
}
四、基本数据类型和结构体不可以直接往数组中放
1、基本数据类型
[arr addObject:@(YES)];
//把基本数据类型转成对象NSNumber
NSNumber *n = [NSNumber numberWithFloat:2.5];
//把数据转回基本数据类型
float f = [n floatValue];
2、结构体
CGPoint p = CGPointMake(100, 100);
//把结构体转成对象NSValue
NSValue *v =[NSValue valueWithCGPoint:p];
[arr addObject:v];
//把数据转回基结构体
CGPoint p1 = [v CGPointValue];