Re: [android-developers] Re: How to solve the problem of launch the apps twice or more?

2010-04-21 Thread Mark Murphy 
Kenneth WON wrote:
 The purpose of this app is to run the service forever until shutdown
 the phone, and after the user leaves the app and return later, the
 service will not launch again, means only have one of this service
 running.

Please don't do that.

First, it's not possible:

http://www.androidguys.com/2009/09/09/diamonds-are-forever-services-are-not/

Second, it's a bad idea to even try:

http://www.androidguys.com/2010/03/29/code-pollution-background-control/

 Now, the problem is it can't only have one of this service running.

What is it?

Services are natural singletons -- there is exactly 0 or 1 copy of the
service running at any point. The goal is for there to be 0 copies of
the service running unless it is actively delivering user-perceived value.

-- 
Mark Murphy (a Commons Guy)
http://commonsware.com | http://twitter.com/commonsguy

_Beginning Android 2_ from Apress Now Available!

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Re: [android-developers] Re: How to solve the problem of launch the apps twice or more?

2010-04-20 Thread Dianne Hackborn 
Make sure you aren't calling startActivity() anywhere, such as in
onCreate().

Look at the log (adb logcat) and event log (adb logcat -b events) to see
what the system is saying about launching and handling activities.

Please don't use singleTask or singleInstance to fix such problems, they are
not needed and have other repercussions you probably don't want.

On Tue, Apr 20, 2010 at 7:07 PM, Kenneth WON kenneth...@gmail.com wrote:

 Hi, thank you for your help!
 But I tried to add android:launchMode=singleTask or
 android:launchMode=singleInstance in the activity before, but it
 seems not work.
 The app still running twice or more at the same time by rotate screen
 or press return button, and launch the app.

 On Apr 21, 4:38 am, ~ TreKing treking...@gmail.com wrote:
  On Tue, Apr 20, 2010 at 2:06 AM, Kenneth WON kenneth...@gmail.com
 wrote:
   But my expected result is just have one and only one app A launch.
 
  http://developer.android.com/intl/fr/guide/topics/manifest/activity-e...
  http://developer.android.com/intl/fr/guide/topics/manifest/activity-e..
 .
 
 ---
 --
  TreKing - Chicago transit tracking app for Android-powered deviceshttp://
 sites.google.com/site/rezmobileapps/treking
 
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Dianne Hackborn
Android framework engineer
hack...@android.com

Note: please don't send private questions to me, as I don't have time to
provide private support, and so won't reply to such e-mails.  All such
questions should be posted on public forums, where I and others can see and
answer them.

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Re: [android-developers] Re: How to solve the problem of launch the apps twice or more?

2010-04-20 Thread Dianne Hackborn 
Starting a service doesn't have anything to do with the activity stack.  It
is only needed if you actually must have a service running even after the
user leaves your app.  (And of course you must have a good plan for how you
will stop the service, so it doesn't get left running forever.)

On Tue, Apr 20, 2010 at 9:05 PM, Kenneth WON kenneth...@gmail.com wrote:

 Hi, Dianne Hackborn,

 Thank you!
 In the main activity, I will start a service, so I am calling
 startService() in onCreate().
 Is that not necessary?



 On Apr 21, 11:25 am, Dianne Hackborn hack...@android.com wrote:
  Make sure you aren't calling startActivity() anywhere, such as in
  onCreate().
 
  Look at the log (adb logcat) and event log (adb logcat -b events) to see
  what the system is saying about launching and handling activities.
 
  Please don't use singleTask or singleInstance to fix such problems, they
 are
  not needed and have other repercussions you probably don't want.
 
 
 
 
 
  On Tue, Apr 20, 2010 at 7:07 PM, Kenneth WON kenneth...@gmail.com
 wrote:
   Hi, thank you for your help!
   But I tried to add android:launchMode=singleTask or
   android:launchMode=singleInstance in the activity before, but it
   seems not work.
   The app still running twice or more at the same time by rotate screen
   or press return button, and launch the app.
 
   On Apr 21, 4:38 am, ~ TreKing treking...@gmail.com wrote:
On Tue, Apr 20, 2010 at 2:06 AM, Kenneth WON kenneth...@gmail.com
   wrote:
 But my expected result is just have one and only one app A launch.
 
   
 http://developer.android.com/intl/fr/guide/topics/manifest/activity-e...

 http://developer.android.com/intl/fr/guide/topics/manifest/activity-e..
   .
 
  
 ---
   --
TreKing - Chicago transit tracking app for Android-powered
 deviceshttp://
   sites.google.com/site/rezmobileapps/treking
 
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  Note: please don't send private questions to me, as I don't have time to
  provide private support, and so won't reply to such e-mails.  All such
  questions should be posted on public forums, where I and others can see
 and
  answer them.
 
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Dianne Hackborn
Android framework engineer
hack...@android.com

Note: please don't send private questions to me, as I don't have time to
provide private support, and so won't reply to such e-mails.  All such
questions should be posted on public forums, where I and others can see and
answer them.

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