我正在制作一个基本的秒表，但是，每次启动计时器时，单击停止，然后再次开始想要继续我的计时器，时钟重新开始为0.我不太清楚该做什么，因为我刚拿起obj-c / Xcode。
#import "StopwatchViewController.h"
bool stopPressed = false;
bool startPressed = false;
int startsPressed = 0;
NSTimeInterval totalTimeInterval;
@interface StopwatchViewController ()
@property (strong, nonatomic) NSTimer *stopWatchTimer; // Store the timer that fires after a certain time
@property (strong, nonatomic) NSDate *startDate; // Stores the date of the click on the start button
@end
@implementation StopwatchViewController
- (void)updateTimer
{
NSDate *currentDate = [NSDate date];
NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate: self.startDate];
totalTimeInterval = timeInterval;
NSDate *timerDate = [NSDate dateWithTimeIntervalSince1970:totalTimeInterval];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat: @"HH:mm:ss.SSS"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]];
NSString *timeString = [dateFormatter stringFromDate:timerDate];
self.stopwatchLabel.text = timeString;
}
- (IBAction)onStartPressed:(id)sender
{
if(startsPressed < 1) {
if(startPressed) return;
startPressed = true;
stopPressed =false;
self.startDate = [NSDate date];
//create the stop watch timer that fires every 100ms
self.stopWatchTimer =
[NSTimer scheduledTimerWithTimeInterval:1.0/100.0
target:self
selector:@selector(updateTimer)
userInfo:nil
repeats:YES];
} else {
startPressed = true;
stopPressed = false;
}
}
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)onStopPressed:(id)sender {
if(stopPressed) return;
stopPressed = true;
startPressed = false;
[self.stopWatchTimer invalidate];
self.stopWatchTimer = nil;
[self updateTimer];
}
- (IBAction)onResetPressed:(id)sender {
if(stopPressed == false) return;
self.stopWatchTimer = 0;
NSString *timeString = @"00:00:00.000";
self.stopwatchLabel.text = timeString;
}
@end
我目前正处于我的起点
#import "StopwatchViewController.h"
bool stopPressed = false;
bool startPressed = false;
int startsPressed = 0;
NSTimeInterval totalTimeInterval;
@interface StopwatchViewController ()
@property (strong, nonatomic) NSTimer *stopWatchTimer; // Store the timer that fires after a certain time
@property (strong, nonatomic) NSDate *startDate; // Stores the date of the click on the start button
@property (nonatomic, strong) NSDate *pauseDate;
@end
@implementation StopwatchViewController
- (void)updateTimer
{
NSDate *currentDate = [NSDate date];
NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate: self.startDate];
totalTimeInterval = timeInterval;
NSDate *timerDate = [NSDate dateWithTimeIntervalSince1970:totalTimeInterval];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat: @"HH:mm:ss.SSS"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]];
NSString *timeString = [dateFormatter stringFromDate:timerDate];
self.stopwatchLabel.text = timeString;
}
- (IBAction)onStartPressed:(id)sender
{
// if(startsPressed < 1) {
// if(startPressed) return;
// startPressed = true;
// stopPressed =false;
// self.startDate = [NSDate date];
//
// //create the stop watch timer that fires every 100ms
// self.stopWatchTimer =
// [NSTimer scheduledTimerWithTimeInterval:1.0/100.0
// target:self
// selector:@selector(updateTimer)
// userInfo:nil
// repeats:YES];
// } else {
//
// startPressed = true;
// stopPressed = false;
//
// }
if(startsPressed < 1) {
if( ! _startDate) {
self.startDate = [NSDate date];
}
else {
if(_pauseDate) {
NSTimeInterval startTime = _startDate.timeIntervalSince1970;
NSTimeInterval pauseTime = _startDate.timeIntervalSince1970;
// the actual elapsed time before we paused
NSTimeInterval elapsedTime = pauseTime - startTime;
// set a new start time to match our elapsed time.
NSTimeInterval currentTime = [NSDate date].timeIntervalSince1970;
NSTimeInterval newStartTime = currentTime - elapsedTime;
_startDate = [NSDate dateWithTimeIntervalSince1970:newStartTime];
_pauseDate = nil;
}
}
}
}
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)onStopPressed:(id)sender {
if(stopPressed) return;
_pauseDate = [NSDate date];
stopPressed = true;
startPressed = false;
[self.stopWatchTimer invalidate];
self.stopWatchTimer = nil;
[self updateTimer];
}
- (IBAction)onResetPressed:(id)sender {
if(stopPressed == false) return;
_startDate = nil;
_pauseDate = nil;
self.stopWatchTimer = 0;
NSString *timeString = @"00:00:00.000";
self.stopwatchLabel.text = timeString;
}
@end
答案 0 :(得分：0)
每次点击＆＃34;开始＆＃34;，此代码都会运行：
self.startDate = [NSDate date];
这会重置您正在使用的开始时间。将其移出某处，使其只发生一次，而不是每次启动计时器时，我认为结果将更接近您想要的结果。也许你可以存储一个额外的BOOL，它会在第一次启动计时器时被切换。
修改：
我忽略了Stonz2提出的非常好的观点。这样做会在启动备份后导致跳过时间。为了解决此问题，您需要在停止计时器时存储单独的NSDate，以表示暂停的＆＃34;暂停＆＃34;时间。然后，当您再次启动计时器备份时，您需要添加＆＃34;暂停＆＃34;时间到了＃34;开始＆＃34;时间，以便继续流动。
我把它扔进了一个项目，这里有一些工作代码。
我添加了一个额外的属性：
@property (nonatomic, strong) NSDate *pauseDate;
在onStopPressed:中，我添加了此内容以初始化暂停时间：
_pauseDate = [NSDate date];
然后，在onStartPressed:中，我添加了以下代码以确保startDate的单个初始化并进行数学计算以获得暂停后经过的时间：
// if we have a start date, don't initialize again
if(! _startDate)
{
self.startDate = [NSDate date];
}
else
{
if(_pauseDate)
{
NSTimeInterval startTime = _startDate.timeIntervalSince1970;
NSTimeInterval pauseTime = _pauseDate.timeIntervalSince1970;
// The actual elapsed time before we paused.
NSTimeInterval elapsedTime = pauseTime - startTime;
// Set a new start time to match our elapsed time.
NSTimeInterval currentTime = [NSDate date].timeIntervalSince1970;
NSTimeInterval newStartTime = currentTime - elapsedTime;
_startDate = [NSDate dateWithTimeIntervalSince1970:newStartTime];
_pauseDate = nil;
}
}
另外，为了使您的重置工作正常，在onResetPressed:中您需要添加：
_startDate = nil;
_pauseDate = nil;
刚试过这个，它就像一个冠军。
编辑3：根据评论主题的完整方法
- (IBAction)onStartPressed:(id)sender
{
if(startsPressed < 1) {
if(startPressed) return;
startPressed = true;
stopPressed =false;
if(! _startDate)
{
self.startDate = [NSDate date];
}
else
{
if(_pauseDate)
{
NSTimeInterval startTime = _startDate.timeIntervalSince1970;
NSTimeInterval pauseTime = _pauseDate.timeIntervalSince1970;
NSTimeInterval elapsedTime = pauseTime - startTime;
NSTimeInterval currentTime = [NSDate date].timeIntervalSince1970;
NSTimeInterval newStartTime = currentTime - elapsedTime;
_startDate = [NSDate dateWithTimeIntervalSince1970:newStartTime];
_pauseDate = nil;
}
}
//create the stop watch timer that fires every 100ms
self.stopWatchTimer =
[NSTimer scheduledTimerWithTimeInterval:1.0/100.0
target:self
selector:@selector(updateTimer)
userInfo:nil
repeats:YES];
} else {
startPressed = true;
stopPressed = false;
}
}
答案 1 :(得分：0)
这是因为您在self.startDate方法中重置了onStartPressed。仅在viewDidLoad:和onResetPressed: