设计类-歌词解析类

1、设计要求

传入一个txt格式的歌词文件，可以输出歌曲作者、名称和时间顺序的歌词内容。

屏幕快照 2016-10-18 下午3.50.53.png

LRCitem.h

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #d12f1b}p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; min-height: 13.0px}p.p3 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo}p.p4 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #008400}p.p5 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px 'Heiti SC Light'; color: #008400}p.p6 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #bb2ca2}span.s1 {font-variant-ligatures: no-common-ligatures; color: #78492a}span.s2 {font-variant-ligatures: no-common-ligatures}span.s3 {font-variant-ligatures: no-common-ligatures; color: #bb2ca2}span.s4 {font-variant-ligatures: no-common-ligatures; color: #703daa}span.s5 {font-variant-ligatures: no-common-ligatures; color: #008400}span.s6 {font: 11.0px 'Heiti SC Light'; font-variant-ligatures: no-common-ligatures; color: #008400}span.s7 {font: 11.0px Menlo; font-variant-ligatures: no-common-ligatures}span.s8 {font-variant-ligatures: no-common-ligatures; color: #4f8187}

#import 

@interface LRCitem : NSObject
{
    float _lrcTime;  //歌词时间点
    NSString *_lrcString;  //歌词
}

-(id)initWithLrcTime:(float)time andLrcString:(NSString *)lrcString;

//setter
-(void)setLrcTime:(float)time;
-(void)setLrcString:(NSString *)lrcString;

//getter
-(float)lrcTime;
-(NSString *)lrcString;

//排序规则:按照歌词时间排序
-(BOOL)isSortByTime:(LRCitem *)aItem;

-(void)printLrcItem;

@end

LrcManager.h

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; min-height: 13.0px}p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo}p.p3 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px 'Heiti SC Light'; color: #008400}p.p4 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #bb2ca2}span.s1 {font-variant-ligatures: no-common-ligatures}span.s2 {font-variant-ligatures: no-common-ligatures; color: #bb2ca2}span.s3 {font-variant-ligatures: no-common-ligatures; color: #703daa}span.s4 {font-variant-ligatures: no-common-ligatures; color: #008400}span.s5 {font: 11.0px 'Heiti SC Light'; font-variant-ligatures: no-common-ligatures; color: #008400}span.s6 {font: 11.0px Menlo; font-variant-ligatures: no-common-ligatures}

@interface LrcManager : NSObject
{
    NSString *_title; //歌曲名
    NSString *_auther; //歌手
    NSMutableArray *_lrcList; //保存词条对象的数组
    
}

//构造方法，传入文件路径，初始化歌词管理器对象
-(id)initWithLrcFile:(NSString *)path;

-(void)showLrcItems; //遍历整个歌词文件

//给用户公开一个接口。输入时间，得到对应内容
+(void)userInterface;

@end

2、方法实现

LRCitem.m

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #d12f1b}p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; min-height: 13.0px}p.p3 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #bb2ca2}p.p4 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo}p.p5 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #008400}p.p6 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #4f8187}p.p7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px 'Heiti SC Light'; color: #008400}span.s1 {font-variant-ligatures: no-common-ligatures; color: #78492a}span.s2 {font-variant-ligatures: no-common-ligatures}span.s3 {font-variant-ligatures: no-common-ligatures; color: #000000}span.s4 {font-variant-ligatures: no-common-ligatures; color: #bb2ca2}span.s5 {font-variant-ligatures: no-common-ligatures; color: #703daa}span.s6 {font-variant-ligatures: no-common-ligatures; color: #3d1d81}span.s7 {font-variant-ligatures: no-common-ligatures; color: #4f8187}span.s8 {font: 11.0px Menlo; font-variant-ligatures: no-common-ligatures}span.s9 {font-variant-ligatures: no-common-ligatures; color: #31595d}

#import "LRCitem.h"

@implementation LRCitem

-(id)initWithLrcTime:(float)time andLrcString:(NSString *)lrcString
{
    self = [super init];
    if (self) {
        _lrcString=lrcString;
        _lrcTime=time;
    }
    return self;
}

//setter
-(void)setLrcTime:(float)time
{
    _lrcTime = time;
}
-(void)setLrcString:(NSString *)lrcString
{
    _lrcString = lrcString;
}

//getter
-(float)lrcTime
{
    return  _lrcTime;
}
-(NSString *)lrcString
{
    return _lrcString;
}

//排序规则
-(BOOL)isSortByTime:(LRCitem *)aItem
{
    if ([self lrcTime] > [aItem lrcTime]) {
        return  YES;
    }
    else
        return NO;
}

-(void)printLrcItem
{
    NSLog(@"time is %.2f, lrc is %@", [self lrcTime], [self lrcString]);
}
@end

LrcManager.m

p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #d12f1b}p.p2 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; min-height: 13.0px}p.p3 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px 'Heiti SC Light'; color: #008400}p.p4 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #008400}p.p5 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo}p.p6 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #bb2ca2}p.p7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 11.0px Menlo; color: #3d1d81}span.s1 {font-variant-ligatures: no-common-ligatures; color: #78492a}span.s2 {font-variant-ligatures: no-common-ligatures}span.s3 {font: 11.0px 'Heiti SC Light'; font-variant-ligatures: no-common-ligatures}span.s4 {font: 11.0px Menlo; font-variant-ligatures: no-common-ligatures}span.s5 {font-variant-ligatures: no-common-ligatures; color: #bb2ca2}span.s6 {font-variant-ligatures: no-common-ligatures; color: #000000}span.s7 {font-variant-ligatures: no-common-ligatures; color: #4f8187}span.s8 {font-variant-ligatures: no-common-ligatures; color: #703daa}span.s9 {font-variant-ligatures: no-common-ligatures; color: #3d1d81}span.s10 {font-variant-ligatures: no-common-ligatures; color: #31595d}span.s11 {font-variant-ligatures: no-common-ligatures; color: #008400}span.s12 {font: 11.0px 'Heiti SC Light'; font-variant-ligatures: no-common-ligatures; color: #008400}span.s13 {font: 11.0px Menlo; font-variant-ligatures: no-common-ligatures; color: #000000}span.s14 {font-variant-ligatures: no-common-ligatures; color: #d12f1b}span.s15 {font-variant-ligatures: no-common-ligatures; color: #272ad8}

#import "LrcManager.h"

#define LrcPath @"/Users/bear/Desktop/传奇歌词.txt"

//类扩展。可以给类扩展实例变量或者方法，可以实现实力变量和方法的私有化（不公开）
@interface LrcManager()   //括号中不允许添加任何东西

-(BOOL)parseLrcFile:(NSString *)path;
-(void)parseLrcTitle:(NSString *)lineString;
-(void)parseLrcAuther:(NSString *)lineString;
-(void)parseLrcItem:(NSString *)lineString;
-(float)parseLrcTime:(NSString *)timeString;

@end

@implementation LrcManager

//构造方法，传入文件路径，初始化歌词管理器对象
-(id)initWithLrcFile:(NSString *)path
{
    self = [super init];
    if (self) {
        _lrcList = [NSMutableArray array];
        [self parseLrcFile:path];  //解析歌词文件
    }
    return self;
}

-(BOOL)parseLrcFile:(NSString *)path
{
    NSString *fileContent = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
    if (!fileContent) {  //判断歌词文件是否读取成功
        return NO;
    }
    //每行歌词都用换行进行了分割
    NSArray *lineArray = [fileContent componentsSeparatedByString:@"\n"];
    NSInteger lineCount = [lineArray count];
    for (NSInteger i=0; i

3、需要注意的

在LrcManager.m文件中，我首次使用了类扩展的功能。
目前的理解就是，扩展的方法为这个类私有的。比如在本程序中，扩展的5个方法都是LrcManager私有的，这几个方法的声明和实现都写在了.m文件中，而没有写到.h文件中。所以，当别的类或者main函数import LrcManager.h文件时，也无法使用这几个类，所以叫做“私有”。
好处就是封装性。

还有一个问题是，这次的类设计比前几个都略复杂，明显感觉到不管是写.h文件的方法声明还是.m文件中的扩展方法，一开始想的都不全面，很可能在实现一个已经声明的方法时发现还需要添加一个新的方法，这就需要边写边添加。思路清晰很重要，弄清几个类之间的关系。

TODO

1、 类方法和对象方法的区别。
2、类扩展功能。