OC一些基本类以及方法

NSObject

1、isKindOf：

//判断是否是该类的对象
- (BOOL)isKindOfClass:(Class)aClass;
BOOL result = [person isKindOfClass:[Person class]];
aClass：可以是父类也可以是本类

2、isMemberOf：

//判断是否是该类的对象
- (BOOL)isMemberOfClass:(Class)aClass;
BOOL result = [p1 isMemberOfClass:[Person class]];
aClass：必须是本类才能返回真

3、respondsToSelector：

//判断是否响应类方法
- (BOOL)respondsToSelector:(SEL)aSelector;
BOOL result = [person respondsToSelector:@selector()];
返回值：BOOL类型
aSelector：必须是本类的方法才能返回真

NSString

创建

//旧语法
1、
NSString *str = [[NSString alloc] initWithString:@"abcdefg"];
NSString *str = [NSString stringWithString:@"abcdefg"];
2、
NSString *str = [[NSString alloc] initWithFormat:@"%@",@"abcdefg"];
NSString *str = [NSString stringWithFormat:@"abcdefg"];
//新语法
NSString *str = @"abcdefg";

增

//在尾部增加字符串，返回字符串类型
- (NSString *)stringByAppendingString:(NSString *)aString;

删

改

[self.text stringByReplacingOccurrencesOfString:string1 withString:string2];