由于Objective C是C的扩展版，所以，可以直接用C的api来读写文件。
但是，ios本身提供了NSFileManager来进行文件操作
-(void)writeFile:(NSString*)filename:(NSString*)data{ //获得应用程序沙盒的Documents目录，官方推荐数据文件保存在此NSArray *path = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString* doc_path = [path objectAtIndex:0]; //NSLog(@"Documents Directory:%@",doc_path); //创建文件管理器对象NSFileManager *fm = [NSFileManager defaultManager]; NSString* _filename = [doc_path stringByAppendingPathComponent:filename]; //NSString* new_folder = [doc_path stringByAppendingPathComponent:@"test"]; //创建目录 //[fm createDirectoryAtPath:new_folder withIntermediateDirectories:YES attributes:nil error:nil]; [fm createFileAtPath:_filename contents:[data dataUsingEncoding:NSUTF8StringEncoding] attributes:nil]; } - (IBAction)sendMailAndWriteFile:(id)sender { //先写入文件 NSString* _username = username.text; NSString* _phone = phone.text ; NSString* _email = email.text ; NSString* _title = title.text ; NSString* filename = @"data.txt"; NSString* data = [NSString stringWithFormat:@"用户名：%@\n电话：%@\nEmail：%@\n地址：%@\n*****\n",_username,_phone,_email,_title,nil]; [self writeFile:filename:data] ; }