iOS實(shí)現(xiàn)毫秒倒計(jì)時(shí)的方法詳解

更新時(shí)間：2017年04月23日 16:34:44 作者：若錦

倒計(jì)時(shí)在我們?nèi)粘ｉ_(kāi)發(fā)中必不可少，最近在公司的一個(gè)項(xiàng)目中就遇到了這個(gè)需求，本文著重介紹的是利用iOS實(shí)現(xiàn)毫秒倒計(jì)時(shí)的方法，文中給出了詳細(xì)的示例代碼，需要的朋友可以參考借鑒，下面來(lái)一起學(xué)習(xí)學(xué)習(xí)吧。

前言

大家應(yīng)該都知道在app開(kāi)發(fā)中，當(dāng)展示限時(shí)優(yōu)惠的某些商品時(shí)，往往會(huì)加一個(gè)倒計(jì)時(shí)，提示用戶(hù)該商品限時(shí)優(yōu)惠所剩的時(shí)間，。那對(duì)于開(kāi)發(fā)者來(lái)說(shuō)，這就需要我們?nèi)?shí)現(xiàn)的是一個(gè)倒計(jì)時(shí)的功能，這個(gè)倒計(jì)時(shí)根據(jù)具體需求，可以以天、小時(shí)、分、秒、毫秒作單位。

今天呢，主要說(shuō)說(shuō)毫秒計(jì)時(shí)器。我們知道秒和毫秒之間的進(jìn)制是1000，也就是說(shuō)1秒=1000毫秒，那我們做毫秒倒計(jì)時(shí)器的時(shí)候是設(shè)置一個(gè)時(shí)間間隔為1毫秒的計(jì)時(shí)器，逐一減少毫秒數(shù)。但是這樣的話(huà)太耗時(shí)了，所以很多的毫秒計(jì)時(shí)器中的毫秒數(shù)只是0-9之間的數(shù)字，這就意味著，這個(gè)毫秒計(jì)時(shí)器的時(shí)間間隔是100毫秒，這樣相比起1毫秒為間隔的計(jì)時(shí)器，其消耗就少了很多，同時(shí)也達(dá)到毫秒計(jì)時(shí)的效果。

那對(duì)于整個(gè)毫秒倒計(jì)時(shí)的實(shí)現(xiàn)思路就是：得到未來(lái)某個(gè)日期的時(shí)間戳和當(dāng)前日期的時(shí)間戳，計(jì)算這兩者之間的時(shí)間差，然后設(shè)置一個(gè)時(shí)間間隔為100毫秒的計(jì)時(shí)器，每隔100毫秒，更新一下倒計(jì)時(shí)器上相應(yīng)的數(shù)值。

實(shí)現(xiàn)方法

自定義一個(gè)UIview，將倒計(jì)時(shí)封裝起來(lái)。

一、在MsecCountDownView.h中增加時(shí)間戳和計(jì)時(shí)器這兩屬性

@interface MsecCountDownView : UIView

@property(nonatomic, assign)double timeInterval;//未來(lái)某個(gè)日期的時(shí)間戳
@property(nonatomic, strong)NSTimer *timer ; //定時(shí)器

@end

二、在MsecCountDownView.m實(shí)現(xiàn)相關(guān)UI及倒計(jì)時(shí)方法

@interface MsecCountDownView (){
UIView *countdownBackView;
CGFloat _passTime;
}
@property(nonatomic, strong)UILabel *tipLabel;
@property(nonatomic, strong)UILabel *hoursLabel;
@property(nonatomic, strong)UILabel *minutesLabel;
@property(nonatomic, strong)UILabel *secondsLabel;
@property(nonatomic, strong)UILabel *millionSecondsLabel;
@property(nonatomic, strong)UILabel *label1;
@property(nonatomic, strong)UILabel *label2;
@property(nonatomic, strong)UILabel *label3;
@property(nonatomic, strong)UILabel *label4;
@end

創(chuàng)建相關(guān)UI

- (instancetype)initWithFrame:(CGRect)frame
{
 self = [super initWithFrame:frame];

 if (self) {

  countdownBackView=[[UIView alloc] initWithFrame:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
  [self addSubview:countdownBackView];
  _tipLabel=[[UILabel alloc] init];
  _tipLabel.frame = CGRectMake(0, 0, 40, countdownBackView.frame.size.height);
  [countdownBackView addSubview:_tipLabel];

  _tipLabel.font = [UIFont systemFontOfSize:12];


  //小時(shí)
  _hoursLabel=[[UILabel alloc] initWithFrame:CGRectMake(_tipLabel.frame.origin.x+_tipLabel.frame.size.width, 0, 35, countdownBackView.frame.size.height)];
  [countdownBackView addSubview:_hoursLabel];
  _hoursLabel.font = [UIFont systemFontOfSize:11];

  _label1=[[UILabel alloc] initWithFrame:CGRectMake(_hoursLabel.frame.origin.x+_hoursLabel.frame.size.width, _hoursLabel.frame.origin.y, 8, countdownBackView.frame.size.height)];
  [countdownBackView addSubview:_label1];

  //分鐘
  _minutesLabel=[[UILabel alloc] initWithFrame:CGRectMake(_label1.frame.origin.x+_label1.frame.size.width, _hoursLabel.frame.origin.y, 20, countdownBackView.frame.size.height)];
  [countdownBackView addSubview:_minutesLabel];
  _minutesLabel.font = [UIFont systemFontOfSize:11];

  _label2=[[UILabel alloc] initWithFrame:CGRectMake(_minutesLabel.frame.origin.x+_minutesLabel.frame.size.width, _hoursLabel.frame.origin.y, 8, countdownBackView.frame.size.height)];
  [countdownBackView addSubview:_label2];

  //秒
  _secondsLabel=[[UILabel alloc] initWithFrame:CGRectMake(_label2.frame.origin.x+_label2.frame.size.width, _hoursLabel.frame.origin.y, 20 , countdownBackView.frame.size.height)];
  [countdownBackView addSubview:_secondsLabel];


  _secondsLabel.font = [UIFont systemFontOfSize:11];

  _label3=[[UILabel alloc] initWithFrame:CGRectMake(_secondsLabel.frame.origin.x+_secondsLabel.frame.size.width, _hoursLabel.frame.origin.y, 8 , countdownBackView.frame.size.height)];
  [countdownBackView addSubview:_label3];


  _millionSecondsLabel=[[UILabel alloc] initWithFrame:CGRectMake(_label3.frame.origin.x+_label3.frame.size.width, _hoursLabel.frame.origin.y, 20, countdownBackView.frame.size.height)];
  [countdownBackView addSubview:_millionSecondsLabel];


   //毫秒

  _millionSecondsLabel.font = [UIFont systemFontOfSize:11];

  _label1.textAlignment=1;
  _label2.textAlignment=1;
  _label3.textAlignment = 1;
  _hoursLabel.textAlignment=1;
  _minutesLabel.textAlignment=1;
  _secondsLabel.textAlignment=1;
  _millionSecondsLabel.textAlignment=1;


  _passTime=0.0;
 }


 return self;
}

生成一個(gè)計(jì)時(shí)器

//得到未來(lái)某個(gè)日期的時(shí)間戳，與當(dāng)前時(shí)間戳相比，得到兩者的時(shí)間差，生成定時(shí)器
- (void)setTimeInterval:(double)timeInterval
{

 _timeInterval = timeInterval ;

 NSDateFormatter *dataFormatter = [[NSDateFormatter alloc] init];
 dataFormatter.dateFormat = @"MM/dd/yyyy HH:mm:ss.SSS";

 //獲取當(dāng)前系統(tǒng)的時(shí)間，并用相應(yīng)的格式轉(zhuǎn)換
 [dataFormatter stringFromDate:[NSDate date]];
 NSString *currentDayStr = [dataFormatter stringFromDate:[NSDate date]];
 NSDate *currentDate = [dataFormatter dateFromString:currentDayStr];

 //優(yōu)惠結(jié)束的時(shí)間，也用相同的格式去轉(zhuǎn)換
 NSDate *date = [NSDate dateWithTimeIntervalSince1970:timeInterval/1000.0];
 NSString *deadlineStr = [dataFormatter stringFromDate:date];
 NSDate *deadlineDate = [dataFormatter dateFromString:deadlineStr];

 _timeInterval=[deadlineDate timeIntervalSinceDate:currentDate]*1000;

 if (_timeInterval!=0)
 {

  //時(shí)間間隔是100毫秒，也就是0.1秒
  _timer = [NSTimer scheduledTimerWithTimeInterval:0.1f target:self selector:@selector(timerAction) userInfo:nil repeats:YES];

  [[NSRunLoop currentRunLoop] addTimer:_timer forMode:UITrackingRunLoopMode];
 }else{
  [countdownBackView removeFromSuperview];

 }

}

實(shí)現(xiàn)每隔100毫秒執(zhí)行的方法，更新倒計(jì)時(shí)器上面相應(yīng)的數(shù)值

// 每間隔100毫秒定時(shí)器觸發(fā)執(zhí)行該方法
- (void)timerAction
{

 [self getTimeFromTimeInterval:_timeInterval] ;


 // 當(dāng)時(shí)間間隔為0時(shí)干掉定時(shí)器
 if (_timeInterval-_passTime == 0)
 {
  [_timer invalidate] ;
  _timer = nil ;
 }
}

// 通過(guò)時(shí)間間隔計(jì)算具體時(shí)間(小時(shí),分,秒,毫秒)
- (void)getTimeFromTimeInterval : (double)timeInterval
{

 //1s=1000毫秒
 _passTime += 100.f;//毫秒數(shù)從0-9，所以每次過(guò)去100毫秒
 _tipLabel.text=@"還剩：";

 _label3.text=@".";
 _label2.text=@":";
 _label1.text=@":";

 //小時(shí)數(shù)
 NSString *hours = [NSString stringWithFormat:@"%ld", (NSInteger)((timeInterval-_passTime)/1000/60/60)];
 //分鐘數(shù)
 NSString *minute = [NSString stringWithFormat:@"%ld", (NSInteger)((timeInterval-_passTime)/1000/60)%60];
 //秒數(shù)
 NSString *second = [NSString stringWithFormat:@"%ld", ((NSInteger)(timeInterval-_passTime))/1000%60];
 //毫秒數(shù)
 CGFloat sss = ((NSInteger)((timeInterval - _passTime)))%1000/100;


 NSString *ss = [NSString stringWithFormat:@"%.lf", sss];

 if (minute.integerValue < 10) {
  minute = [NSString stringWithFormat:@"0%@", minute];
 }


 self.hoursLabel.text = [NSString stringWithFormat:@"%@",hours];
 self.minutesLabel.text = [NSString stringWithFormat:@"%@",minute];
 self.secondsLabel.text = [NSString stringWithFormat:@"%@",second];
 self.millionSecondsLabel.text = [NSString stringWithFormat:@"%@",ss];

 if (timeInterval - _passTime <= 0) {
  [countdownBackView removeFromSuperview];
  [self removeFromSuperview];
 }

}

三、在ViewController.m給倒計(jì)時(shí)器賦值，實(shí)現(xiàn)自己想要的倒計(jì)時(shí)

- (void)viewDidLoad {
 [super viewDidLoad];

 msecView=[[MsecCountDownView alloc] initWithFrame:CGRectMake(50, 100, self.view.frame.size.width-100, 16)];
 [self.view addSubview:msecView];

 NSDateFormatter *formatter = [[NSDateFormatter alloc] init];

 [formatter setDateStyle:NSDateFormatterMediumStyle];

 [formatter setTimeStyle:NSDateFormatterShortStyle];

 [formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss.SSS"];


 NSDate* date = [formatter dateFromString:@"2017-04-11 15:10:00.000"];
 //將日期轉(zhuǎn)換成時(shí)間戳
 NSInteger timeSp = [[NSNumber numberWithDouble:[date timeIntervalSince1970]] integerValue]*1000;

 msecView.timeInterval=timeSp;

}

這樣就實(shí)現(xiàn)倒計(jì)時(shí)的功能了。但是使用倒計(jì)時(shí)還需要注意一點(diǎn)，當(dāng)離開(kāi)該頁(yè)面的時(shí)候，記得把定時(shí)器暫停，等回到該頁(yè)面的時(shí)候再啟動(dòng)倒計(jì)時(shí)。

這個(gè)可以通過(guò)以下兩方法實(shí)現(xiàn)。

-(void)viewWillAppear:(BOOL)animated{

// 頁(yè)面出現(xiàn)時(shí)，開(kāi)啟計(jì)時(shí)器 
 [msecView.timer setFireDate:[NSDate distantPast]];

}
-(void)viewWillDisappear:(BOOL)animated{
// 頁(yè)面消失時(shí)，暫停提示器
 [msecView.timer setFireDate:[NSDate distantFuture]];
}

如有需要，可通過(guò)下面兩種方法下載demo

一：GitHub上下載

二：本地下載

總結(jié)

以上就是這篇文章的全部?jī)?nèi)容了，希望本文的內(nèi)容對(duì)大家的學(xué)習(xí)或者工作能帶來(lái)一定的幫助，如果有疑問(wèn)大家可以留言交流，謝謝大家對(duì)腳本之家的支持。

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