[Android-development] Warm application start time

[Лагнер, Сергей]

I have tried it in Qml like that:

   * applicationWindow.hide();*

but it does not work for me. So I did the trick. I call java Activity
method

    *moveTaskToBack(true);*

through JNI. I'm testing it and it works well so far. Exactly like HOME or
OVERVIEW buttons do. But I'm not sure.

2016-06-15 13:35 GMT+06:00 Xavier Bigand <flamaros.xavier at gmail.com>:

> You simply have to hide the window on the back button instead of closing
> it, it should work.
>
> 2016-06-15 9:16 GMT+02:00 ekke <ekke at ekkes-corner.org>:
>
>> Am 15.06.16 um 08:00 schrieb Лагнер, Сергей:
>>
>> Indeed. I have checked it carefully. I call QApplication quit if my
>> StackView has the last Page.
>> But what should I do to hide the app once user presses the back button?
>>
>> just noticed:
>> if app becomes inactive because user uses Home or Overview Button,
>> re-opening is very fast
>> if user uses BACK button app is closed and re-opening took a long time
>>
>> you can overwrite BACK behavior:
>>
>>         Keys.onBackPressed: {
>>
>>             event.accepted = true
>>
>>             // ...
>>
>>         }
>>
>>
>> But I don't know how to set the correct state now to avoid closing the
>> app from BACK and doing the same as from HOME
>>
>> ekke
>>
>>
>> 2016-06-15 1:57 GMT+06:00 Xavier Bigand <flamaros.xavier at gmail.com>:
>>
>>> I don't really understand, because if the process isn't killed Android
>>> don't release anything that you have loaded. So normally when the OS put
>>> the application back to the active state it should be really fast.
>>>
>>> With our app we don't have a such issue.
>>>
>>> Maybe you catch the back button in QML or C++ and you call the
>>> QApplication quit method or something else that finally make your
>>> application exiting.
>>>
>>> Try to launch your app with a debugger, you'll see in the console if the
>>> process is killed when pressing the back button.
>>>
>>> 2016-06-14 21:31 GMT+02:00 Лагнер, Сергей < <developer at lagner.ru>
>>> developer at lagner.ru>:
>>>
>>>> Thank you for advice
>>>>
>>>> We are already doing our best to optimize QML loading time. We use
>>>> Loaders from QML side
>>>> and lazy loading for models from C++ side. But the application still
>>>> too heavy.
>>>> It takes 6 sec approximately to launch on Nexus 5.
>>>>
>>>> Therefore we are looking for other ways to improve our app.
>>>>
>>>> Now I'm care about warm start.
>>>>
>>>> Lets consider the following scenario:
>>>> - I launch the app. It takes 6 sec.
>>>> - Press back and see a home screen
>>>> - Launch the app again in a second. And again it takes 6 sec.
>>>>
>>>> That is mean that all resources were freed and second start was
>>>> completely from scratch.
>>>> I wonder if I could speed up the second(warm) start from java side.
>>>> For example, is it possible so save preloaded native libraries until
>>>> the OS has the real lack of memory?
>>>>
>>>> 2016-06-14 21:56 GMT+06:00 Xavier Bigand < <flamaros.xavier at gmail.com>
>>>> flamaros.xavier at gmail.com>:
>>>>
>>>>> Hi,
>>>>>
>>>>> If you are using QML you may have to use Loaders to avoid loading of
>>>>> GUI parts that are not displayed directly.
>>>>> You can also take a look to the QtQuick compiler to improve qml
>>>>> loading.
>>>>> There is a profiler on QtCreator for QML which can help you to find
>>>>> your binding that are slow, be sure to not having binding loops.
>>>>>
>>>>> 2016-06-14 16:33 GMT+02:00 Лагнер, Сергей < <developer at lagner.ru>
>>>>> developer at lagner.ru>:
>>>>>
>>>>>> Hi all.
>>>>>>
>>>>>> I'm trying to optimize start time of my android application. For now
>>>>>> I'm interested in warm start time
>>>>>> when the user presses back and quickly returns to the app. If we
>>>>>> consider java application the
>>>>>> warm start is faster, it seems like android caches something or so.
>>>>>> But it does not work for Qt applications. My application spends
>>>>>> constant time for each start, even if I closed it a second ago.
>>>>>>
>>>>>> Is there any way to optimize warm start of Qt application?
>>>>>> Any hints are highly appreciated.
>>>>>>
>>>>>> Thanks,
>>>>>> Sergey
>>>>>>
>>>>>> _______________________________________________
>>>>>> Android-development mailing list
>>>>>> Android-development at qt-project.org
>>>>>> http://lists.qt-project.org/mailman/listinfo/android-development
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> Xavier
>>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> Xavier
>>>
>>
>>
>>
>> _______________________________________________
>> Android-development mailing listAndroid-development at qt-project.orghttp://lists.qt-project.org/mailman/listinfo/android-development
>>
>>
>>
>> --
>>
>> ekke
>>
>> _______________________________________________
>> Android-development mailing list
>> Android-development at qt-project.org
>> http://lists.qt-project.org/mailman/listinfo/android-development
>>
>>
>
>
> --
> Xavier
>
> _______________________________________________
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>
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