I want to use a timer in a windows mobile app. Of course, this is not the problem.
The problem: the timer needs to be called even during standby and sleep mode.
Simply switching off the sleep mode is not really an option, since the app needs to comply to windows marketplace for mobiles requirements, and regarding to requirement 5.2 a marketplace app "shall not modify power management options".
Is there a system timer, which could be used to get an event called (like CeSetUserNotificationEx can be used to get an app started)?
Or how would I create a persistent timer?
CeRunAppAtTime can be used to set a named system event (not just to run an app). If the device is in sleep mode when that time arrives, it will wake.
Related
I have an app that needs to perform some actions based on a TTimer.
When the app becomes inactive (in background), the timer stops working.
I could not find any relevant options for UIBackgroundModes.
How can I make a timer keeps running?
iOS pauses your app automatically shortly after it goes into the background. You need to let iOS know that you are going to continue operating in the background.
In Project > Options > Version Info you can add to the array key UIBackgroundModes the string values for the services that require to continue running in the background. This gets added to the info.plist for your project on iOS.
You can consult Apple's documentation on what these values do . . .
Value - Description
audio - The app plays audible content in the
background.
location - The app provides location-based information to
the user and requires the use of the standard location services (as
opposed to the significant change location service) to implement this
feature.
voip - The app provides Voice-over-IP services. Apps with this
key are automatically launched after system boot so that the app can
reestablish VoIP services. Apps with this key are also allowed to
play background audio.
fetch - The app requires new content from the
network on a regular basis. When it is convenient to do so, the
system launches or resumes the app in the background and gives it a
small amount of time to download any new content. This value is
supported in iOS 7.0 and later.
remote-notification - The app uses
remote notifications as a signal that there is new content available
for download. When a remote notification arrives, the system launches
or resumes the app in the background and gives it a small amount of
time to download the new content. This value is supported in iOS 7.0
and later.
newsstand-content - The app processes content that was
recently downloaded in the background using the Newsstand Kit
framework, so that the content is ready when the user wants it. This
value is supported in iOS 5.0 and later.
external-accessory - The app
communicates with an accessory that delivers data at regular
intervals. This value is supported in iOS 5.0 and later.
bluetooth-central - The app uses the CoreBluetooth framework to
communicate with a Bluetooth accessory while in the background. This
value is supported in iOS 5.0 and later.
bluetooth-peripheral - The app
uses the CoreBluetooth framework to communicate in peripheral mode
with a Bluetooth accessory. The system will alert the user to the
potential privacy implications of apps with this key set. See Best
Practices for Maintaining User Privacy for more information on
privacy. This value is supported in iOS 6.0 and later.
Notice you need to actually select the mode that matches what you are doing. You can't just select fetch when really all you are doing is background processing.
Is there a way to know if the app is sent to background or brought to foreground. I don't mean Suspended and Resuming events.
For example, user leaves the app to check something on Facebook app for a min. And then return to back to my app. So suspention doesn't take effect on this scenario. Then how to know user is back to the app on app.cs level?
As stated in the MSDN documentation:
Your app doesn't receive an activation event when app visibility changes, because the app is still running. Windows simply switches to and from the app as necessary. If your app needs to do something when the user switches away and back, it can handle the visibilitychange event (for HTML) or Window.VisibilityChanged event (for XAML).
Is it possible to create an app the runs in the background? If so is there any samples out there for this?
In Windows Phone OS 7.1 you can actually use Background Agents now to perform tasks in the background.
from MSDN:
Scheduled Tasks and background agents allow an application to execute
code in the background, even when the application is not running in
the foreground. The different types of Scheduled Tasks are designed
for different types of background processing scenarios and therefore
have different behaviors and constraints.
You can use a PeriodicTask or ResourceIntensiveTasks. Read more about it in the MSDN article above.
And here's some sample code for you to integrate background agents into your existing app.
Sample Code: Background Agents in Mango
An application in the foreground can continue to run when the phone screen is locked(not background but...) by setting the PhoneApplicationService.ApplicationIdleDetectionMode property. By setting up your application to run when the phone screen is locked, a user is able to access the application quickly upon unlock. However, when your application runs under a locked screen, it could consume power outside of the user's control. For this reason, your application must minimize power usage when running under a locked screen
At the moment there is no way to create application that runs in background.
True multitasking for 3rd party Windows Phone 7 apps will come as an OS upgrade later this year. However, unless the app has to absolutely run in the background (like Pandora etc.), we as developers share some responsibility in making our apps feel at home with the rest of the OS.
Windows Phone OS offers app developers chances to save state of their applications to give the end users the feeling that it never stopped running; this is essentially the same as in other mobile platforms. As your app is being deactivated/closed, you have the option to "Tombstone" your state so that your users can come back to just where they left with BackStack navigation or future launches. Channel 9 had a nice set of demos & labs around tombstoning, found here.
Hope this helps!
I'm a complete noob when it comes to WP7. From what I know of it, in WP7 you wouldn't be able to make an alarm clock app. As in, start app, set alarm for an hour from now, close app, app launches and rings alarm after an hour is up.
Is this not possible in WP7? Or is there some way of doing it that I'm not aware of? I have seen a workaround for a stopwatch using tombstoning, but that doesn't seem like it would work here.
With Windows Phone 7 [for 3rd party developers] it's not possible to write an application that runs in the background on the phone. (This was a deliberate decision with regards to maintaining performance and battery life - not a limitation of the OS which is fully multi-tasking.)
If you really want the user to be notified of something at a specific time, regardless of whether your application is running you'll need to have this monitored from a process on an external server and then send a [toast] notification to the user at the appropriate time.
Learn more about push notifications at http://msdn.microsoft.com/en-us/library/ff402537(VS.92).aspx
My application uses the Win32 SetSuspendState() API to trigger system suspend or hibernation when it has finished doing a lengthy task.
The API accepts a parameter "ForceCritical" which determines whether or not the system suspends immediately or whether it broadcasts PBT_APMQUERYSUSPEND first to allow other apps the chance to cancel the suspend. My app uses this to play nicely with other apps like Media Player, so it doesn't suspend if you're listening to music or something.
For some reason, starting with Vista, MS have changed things so this parameter is ignored so SetSuspendState immediately causes a suspend and other applications have no opportunity to stop it.
Does anyone know how I can get the desired "polite" behaviour back again on Vista?
MSDN says
To prevent the system from transitioning to a low-power state in Windows Vista, an application must call SetThreadExecutionState to inform the system that it is in use
I would guess that WMP does this, but older apps don't. You could probably emulate this by sending the WM_POWERBROADCAST:PBT_APMQUERYSUSPEND message to all top level windows and check their return values (Send the message with a timeout so a hung app does not hang your app)