I have a variable that keeps track of user statistic I want to reset at the beginning of each day. How can I do that?
Since the application is not allowed to run in the background, it seems I will have to do the check every time the application is active but I don't know how to reset the variable I have only once. This is the function I wanted to use:
let beginingOfDay = NSCalendar.currentCalendar().startOfDayForDate(NSDate())
func resetCurrentTime(){
// Date comparision to compare current date and begining of the day.
let dateComparisionResult:NSComparisonResult = NSDate().compare(beginingOfDay)
if dateComparisionResult == NSComparisonResult.OrderedDescending || dateComparisionResult == NSComparisonResult.OrderedSame {
// Current date is greater or equal to end date.
currentTime = 0 //reset the time tracker
}
}
I wanted to use this function to check when the application is launched but the problem is that the application could be launched many time a day. How I can reset my variable only once at the beginning of a day if the user is using the application or when the application becomes active or is launched for the first time that day?
Thanks
You can store in the user defaults this value.
So the flow is the following:
When the app is launched or became active you check whether the value of the variable in the user defaults is the same as the current day (e.g. 25/07/2016), then do nothing.
If the value is different, then you update the value in the user defaults with the current day.
If the app is running and the date is changed, you can update the value of your variable by subscribing to this notification:
UIApplicationSignificantTimeChangeNotification
Related
I want to show a text for the first time running like "Hi, my name is NAVI." and then when the player will start the game again the next time it will another text for example "Welcome back."
Using player prefs is probably the easiest solution, though definitely not the only one*.
Due to the lack of boolean playerpref I usually opt to use SetInt/GetInt instead, but that's personal preference. You could also do it with a string or float.
private void Start()
{
if(PlayerPrefs.GetInt("HasLaunched", 0) == 0)//Game hasn't launched before. 0 is the default value if the player pref doesn't exist yet.
{
//Code to display your first time text
}
else
{
//Code to show the returning user's text.
}
PlayerPrefs.SetInt("HasLaunched", 1); //Set to 1, so we know the user has been here before
}
Playerpref stores values between sessions, so the next session will still have "HasLaunched" set to 1. This is however stored on the local device. so users can manually reset it if they'd really want to.
If you ever want to show the "first launch" text again, simply set HasLaunched back to zero, or delete it altogether with DeleteKey("HasLaunched");
*There are plenty of alternative solutions, like storing it in a config file locally, or using a remote database (this would be required if you don't want users to be able to reset it). They would however come down to the same principle. Setting a value to true or 1 somewhere, and checking that value on launch.
My current project is a timer which uses a date picker to set the amount of time the user wants before the timer goes off (say 1 minute, 6 hours and two minutes etc.). The problem lies in the amount of time that the date picker believes it has been set for. Below is the code which I am using to set the time.
#IBOutlet weak var datePicker: UIDatePicker!
var timeAmount:Double = 0
#IBAction func startButton() {
timeAmount = Double(datePicker.countDownDuration)
let trigger = UNTimeIntervalNotificationTrigger(timeInterval: timeAmount, repeats: false)
}
Here it can be seen that the function startButton, sets the value of timeAmount to be the amount of time that the date picker is set for. This timeAmount value is then used in a local notification as the time.
The issue is that the datePicker.countDownDuration is never correct. If it is set for one minute, then timeAmount may return a value of 99 seconds, 62 seconds, 67 seconds etc. It is just completely random.
Maybe I do not entirely understand how the .countDownDuration feature works, however from everything I have read, this should return a value of 60 seconds.
Any thoughts and suggestions on the matter will be very much appreciated, thank you.
By default, the UIDatePicker will take the current second value for the calculation.
timeAmount = (number of minutes selected in picker * 60) + current time second value.
For example:
If the current time is 13:40:25 (1 PM 40 minutes 25 seconds) and you have selected one minute in the date picker, the value of timeAmount in this case is 85.
timeAmount = (1*60) + 25
This will solve your problem.
Go to your Storyboard and select UIDatapicker. Navigate to Date option in Attributes inspector.
Click the Dropdown and change it to Custom from Current Date.
You will see a new text field with the current time as the custom date.
Just change the second field to 00.
Run the App now. Now it will take 0 as the value for the second and you will able to see seconds value correctly based on the time you are choosing in the date picker.
Hope this will solve your problem.
I set the minimum date in the date picker like so:
override func viewDidLoad() {
super.viewDidLoad()
datePicker.minimumDate = NSDate()
}
This does prevent the user from rolling back the date, sort of. The user can roll the date dial back but it just snaps back to the current date. The problem is that when this happens, the datetime is set to midnight instead of the current time for any and all future changes and it also executes the event that runs when the date changes. This is a problem when it comes to my code and sliders in my UI. It thinks that the date changed when it did not, yeah it bounces back but it's too late by this point my code runs assuming the date changed. How do I prevent the user from rolling the dial back at all?
Steps to reproduce:
1) Set minimum date as shown above.
2) Set up an event for date change
3) Set event to print(datePicker.date)
4) Roll Dial forward
5) Roll dial backward beyond current date.
6) Roll dial forward
Notice the time is now permanently set to midnight from this point forward.
A quick fix/workaround was to set datePicker.date = NSDate() in the date changed event function.
Is there anyway to show the notification with swift every 15 seconds ? I checked that via
notification.fireDate=NSDate(timeIntervalSinceNow: 15)
but it doesn't work everytime it just showed once , how we can do it as a loop ?
You can't schedule a notification every 15 second. The minimum time between notifications it is 1 minute which it is also very unlikely needed.
var repeatInterval: NSCalendarUnit { get set }
Description The calendar interval at which to reschedule the
notification. If you assign a calendar unit such as weekly
(NSWeekCalendarUnit) or yearly (NSYearCalendarUnit), the system
reschedules the notification for delivery at the specified interval.
Note that intervals of less than one minute are not supported. The
default value is 0, which means that the system fires the notification
once and then discards it.
So just set it up as follow:
notification.repeatInterval = .Minute
You can set localNotification.repeatInterval property which as to be of type NSCalendarUnit
I'd like to detect from within my app whether the iPhone has been rebooted since last time my app was started. I need to do this because my app uses the timer since last system reboot to clock a user's time and I want to detect reboot so I can invalidate the time.
Is there anywhere I could extract the information from the system console log like reboot , crashes ? The organizer in xcode can access it , maybe I can too.
If not , can you think of other ways to get this information?
This seems like it would work:
get the time since last reboot, and for this example, let's store it in a variable called 'tslr' (duration in milliseconds I guess, BTW, how do you get that?)
get the current time, store it in variable 'ct' for example
compute the last reboot time (let's call it 'lr'), we have: lr = ct - tslr
store 'lr'
Next time your application gets started, load the previous value for 'lr', compute the new one, and if they differ, you have detected a reboot (you'll probably have to tolerate a small difference there... a couple milliseconds perhaps).
I think it would be pretty tough to fool that... the user would have to tamper their phone time very precisely, and they would have to start your application at a very precise moment on top of that, exactly when the new 'lr' would be identical to the previous one... pretty tough to do, the probability of them being able to do that is very close to 0 I think. And you don't need any internet connection to do that...
The new 'lr' would be identical to the previous one in the following cases only:
phone was not rebooted, and time was not changed
time was tampered with, AND the user managed to start your application at the precise millisecond to fool your algorithm (chances of that happening more than ultraslim)
// Returns true if device has rebooted since last time
private func deviceRebootedSinceLastTime() -> Bool {
let userDefaults = NSUserDefaults.standardUserDefaults()
let systemUptime = NSProcessInfo.processInfo().systemUptime;
let timeNow = NSDate().timeIntervalSince1970
let dateOfLastReboot = NSDate(timeIntervalSince1970: timeNow-systemUptime)
var didDeviceRebootSinceLastTime = false
if let storedDateOfLastReboot:NSDate = userDefaults.objectForKey("deviceLastRebootDate") as? NSDate {
if Int(dateOfLastReboot.timeIntervalSinceDate(storedDateOfLastReboot)) < 1 { //
print("Reboot time didn't change - date: \(dateOfLastReboot)");
}
else {
print("Reboot time has changed - from: \(storedDateOfLastReboot) to \(dateOfLastReboot)");
didDeviceRebootSinceLastTime = true
}
}
else {
print("Reboot time is saved for the first time")
didDeviceRebootSinceLastTime = true // first time we save value
}
userDefaults.setObject(dateOfLastReboot, forKey: "deviceLastRebootDate")
userDefaults.synchronize() // don't forget this!!!
return didDeviceRebootSinceLastTime;
}
Zoran's answer is the right way to go; it's the closest you are going to get without a network connection. (neither the cellular subsystem, nor the syslog are accessible for security reasons)
If you are looking to prevent malicious users from generating fake time data, have some central server (or trusted local server for enterprise deployments) track time-related events for you.
Get and save the time either from the iPhone or from NIST and the current runtime from the BSD uptime function. For NIST time see How can I get the real time in iPhone, not the time set by user in Settings?
When you want to check for a reboot get new values of these, compute the elapsed time for each and compare the elapsed times. Based on the difference you should be able to determine a reboot.
Here is one I made. It takes the current time in GMT and the time since last reboot to extrapolate a date for when the device was last restarted. Then it keeps track of this date in memory using NSUserDefaults. Enjoy!
Note: Since you want to check this since last time app was started, you need to make sure you call the method anytime the app is started. The easiest way would be to call the method below in +(void)initialize { and then also whenever you need to check it manually
#define nowInSeconds CFAbsoluteTimeGetCurrent()//since Jan 1 2001 00:00:00 GMT
#define secondsSinceDeviceRestart ((int)round([[NSProcessInfo processInfo] systemUptime]))
#define storage [NSUserDefaults standardUserDefaults]
#define DISTANCE(__valueOne, __valueTwo) ((((__valueOne)-(__valueTwo))>=0)?((__valueOne)-(__valueTwo)):((__valueTwo)-(__valueOne)))
+(BOOL)didDeviceReset {
static BOOL didDeviceReset;
static dispatch_once_t onceToken;
int currentRestartDate = nowInSeconds-secondsSinceDeviceRestart;
int previousRestartDate = (int)[((NSNumber *)[storage objectForKey:#"previousRestartDate"]) integerValue];
int dateVarianceThreshold = 10;
dispatch_once(&onceToken, ^{
if (!previousRestartDate || DISTANCE(currentRestartDate, previousRestartDate) > dateVarianceThreshold) {
didDeviceReset = YES;
} else {
didDeviceReset = NO;
}
});
[storage setObject:#(currentRestartDate) forKey:#"previousRestartDate"];
[storage synchronize];
return didDeviceReset;
}