I am working on an mobile app that requires me to change the text displayed either on a weekly or a monthly basis, but I don't want to require the users to have to update the app every day or every week in order to see the changes. I would love suggestions on how to do this.
As a high-level answer, check the device date and display the proper text, if it is fixed and known ahead of time.
If not, have a file or api call send down the information and the next date of when the server should be checked for the next set of data.
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I'm currently building an app that allows user to share events and check in their guests simultaneously using multiple phones. I managed to set up CKQuerySubscription and update, delete and create works fine but only on the primary phone (the one sharing the event).
I recently found out that for a non-primary user to get notifications, it has to get notifications from CKDatabaseNotification which i set up and it works as I am getting remote notifications when I make changes through CloudKit Dashboard.
But the notification i get (CKDatabaseNotification) does not come with anything that would allow me to find what records changed. I've tried casting it as CKNotification as suggested on this link but as expected it fails.
I have a custom zone set up and my questions are as below:
How do I get any information about what changed from a CKDatabaseNotification?
Am I even doing that the right way? I've read somewhere else as well that some people managed to set up subscription through CKQuerySubscription on a shared database as long as it is on a custom zone, which I have but my codes told me subscription failed.
The CKDatabaseNotification will only tell you that something has changed, not what it is. The recommended path forward is you use a CKFetchDatabaseChangesOperation to find out what record zones have changes. Then you use the record zone IDs from that operation in a CKFetchRecordZoneChangesOperation to get all the changes.
There's a bit more information in the CloudKit Quick Start Guide
I'm cherry picking some relevant info below:
After app launch or the receipt of a push, your app uses CKFetchDatabaseChangesOperation and then CKFetchRecordZoneChangesOperation to ask the server for only the changes since the last time it updated.
The key to these operations is the previousServerChangeToken object,
which tells the server when your app last spoke to the server,
allowing the server to return only the items that were changed since
that time.
First your app will use a CKFetchDatabaseChangesOperation to find out
which zones have changed
Then
Next your app uses a CKFetchRecordZoneChangesOperation object with the
set of zone IDs you just collected to do the following:
• Create and update any changed records
• Delete any records that no longer exist
• Update the zone change tokens
The WWDC video CloudKit Best Practices addresses this topic as well.
I have an app which works both offline and online. I have a request from the client to embed a functionality which will disallow the user from using certain functionality after some days, 7 days, for example.
If online I can easily achieve this task by comparing the time-interval between server time.
But in offline mode, this has been a problem. I have tried to achieve this by saving server timestamp in USerDefault and when the app comes in the foreground, compare the current NSDate with the one saved to get time interval. But, what I found is this can be hacked easily by manipulating the date and time in Settings and those functionalities in app works perpetually.
Another solution I have thought is to disable the app if date time is not set to automatically in the setting. But, found that Apple has not disclosed the API to access date and time.
I have searched for other answers on the internet, but could not find the solution to fix this issue. Also, tried some offline game app to check but found that I can change date and time to manipulate their functionality.
So, isn't there any robust solution to fix this issue? Any help is highly appreciable.
you can manage timings on the server through API calls when the user
goes offline or log out or something. so you can easily get to know
your exact timing and it is also not hackable :)
I am coding in Xcode 6.1.1 with objective-c.
In my app it is critical that I use the correct time.
I only want the app to use the time of the device when the time is synced with the servers.
If an user is somehow using his/her own "weird" time the app should detect that and tell the user to switch back to use the app.
I know there is NSSystemClockDidChangeNotification, but that only gives back when the time is changed. It does not give back what the change was and if the user switched to "custom" time or synced back to an NTP server.
Question: How do I detect if an user is connected to an NTP server or not?
Maddy is right that you can't specifically find this out from iOS.
However, in the past I've delivered a client for a premium subscription service that had a similar need to know if the user was messing with time. In particular we needed to verify this when there was no network available, in order to prevent the user from accessing premium content after their subscription had lapsed. The very simple mechanism we used was as follows (IIRC):
every time the app launches or comes in from the background, record the current time (eg: in NSUserDefaults)
compare the current time to the last recorded time--if the current time is earlier than the last recorded time, force the user to go online and sign in to the service.
I don't claim it is 100% foolproof, but for our purposes we felt it was good enough to prevent users from trying to circumvent time-based restrictions on accessing premium content.
I have a couple apps on the Apple App Store and would like some way to send announcements to users whenever I want. Basically, I want to remotely change the text of an IUAlertview and only trigger it to appear if I want it to (upon app opening and only if I updated the message).
So far I have no problem making the IUAlertview appear on when the app opens, and I can easily program an NSUserDefault flag to only make the IUAlertview appear under certain circumstances, but really have no idea how to dynamically change the UIAlertview text without resubmitting my app to Apple continuously.
Can someone please explain how this is done? Thanks!
One way to do this is to have your app periodically (or upon each launch) check a file on a website that you control and if there is changed text (or a version number, or newer date than the last time an alert was displayed) there, then display that changed text in your UIAlertView.
I have a game where users can do a certain activity once per hour. How can I make sure it's been an hour since the last time they attempted something without them just changing their devices current time in settings?
Also, if I wanted to prevent the user from just deleting the app and re-installing it so they could constantly keep trying without having to wait to full hour is there any way I can store data on the device even after an app delete or would that have to be a server thing?
If I don't have a server can anyone think of a clever way to do this via Free in-app purchases or something?
The only way to persist data in a way that survives app reinstalls is to save it to the keychain. This works, because keychain data may be shared across multiple applications; the rest of your application's data is removed on uninstall.
If you need a reliable way to tell the current time, the device must be connected to the internet. In this case you would be able to check the current time using one of the time services through the NTP.
That sounds like exactly the sort of task you would need a server for.
When the user wants to perform this limited action, have them ask the server for permission. You can log the user's ID and request time, decide if they can execute the action, then return a small success/failure message. Works if they change their clock, works if they log in from a different device, works if they wipe the device data.