[Android-development] Android Splash Screen

Liang Jian jianliang79 at gmail.com
Wed Dec 16 13:54:17 CET 2015 

    Thank you, I'll try this method When I have enough time :-)

On Tue, Dec 15, 2015 at 9:43 PM, Ben Lau <xbenlau at gmail.com> wrote:

> Hi Liang Jian,
>
> May be we could avoid this problem with a more simple way. I have
> performed an experiment:
>
> 1. Create a custom theme and set windowBackground to splash.xml
> 2. splash.xml is a white background image plus a Qt logo
> 3. Set android.app.splash_screen_drawable to splash.xml
> 4. Load a QML scene with white background only
>
> In this condition, the screen flicker won't be happen. I will only see the
> Qt logo disappear.
>
> Then I changed to load a more complex scene, the screen flicker will
> happen obviously.
>
> Therefore, I made an assumption that screen flicker may happen when there
> are too many things to draw on startup (Construction of QtSurface). So we
> may avoid it by showing a pure color image background first. Then show the
> rest of content by fade-in animation.
>
> It seems to be working well on my Nexus 5.
>
> Here is my code:
>
> quickandroid/main.qml at DEV ยท benlau/quickandroid
> <https://github.com/benlau/quickandroid/blob/DEV/examples/quickandroidexample/main.qml>
>
>
>
>
>
>
> On 3 November 2015 at 23:11, Liang Jian <jianliang79 at gmail.com> wrote:
>
>>     Hi Ben Lau,
>>     After some investigation I found the flicker was mainly caused by two
>> reason:
>>
>>     1) When we show the QQuickView, qt will create a platform window for
>> it, it is in fact a android SurfaceView, in QtActivityDelegate.createSurface()
>> before the first QtSurface(which extends SurfaceView) was created qt will
>> reset window's background drawable to the 'windowBackground' of the current
>> theme, but the custom theme with the background image we want has been
>> replaced by a system defined theme in QtActivity.onCreate().  I try to
>> remove the code which reset window's background drawable and rebuild qt,
>> but the flicker was still there which is caused by the following reason.
>>
>>     2) After the SurfaceView was created and before qt create EGL surface
>> from it the screen will be black even if I set a  background color to this
>> SurfaceView object. After some googling I found this:
>> http://stackoverflow.com/questions/8772862/surfaceview-flashes-black-on-load/12636285#12636285
>>     It seems that the flicker is unavoidable unless we use the dirty
>> trick described in the post.
>>
>>     It is too complex for me to submit a patch to fix this issue :-(
>>
>> On Mon, Nov 2, 2015 at 7:34 PM, Ben Lau <xbenlau at gmail.com> wrote:
>>
>>> Hi Liang Jain,
>>>
>>> It will be great if you can find out the problem. Moreover, I think Qt
>>> dev team may also consider to remove their own splash screen support which
>>> is quite meaningless. They just not to clear window background during
>>> onCreate() will be helpful
>>>
>>> On 1 November 2015 at 21:20, Liang Jian <jianliang79 at gmail.com> wrote:
>>>
>>>>      Hi Ben Lau,
>>>>      You are right, with both methods applied the flicker will be
>>>> minimal. I think now the flicker may be related to the creation of EGL
>>>> surface, I will do more investigation into it.
>>>>
>>>> On Sun, Nov 1, 2015 at 9:05 PM, Ben Lau <xbenlau at gmail.com> wrote:
>>>>
>>>>> Hi Liang Jian,
>>>>>
>>>>> I mean to mix your method (custom AndroidStyle) together with
>>>>>  android.app.splash_screen_drawable. It should have no impact for splash
>>>>> screen loading time. It can be shown immediately after clicked to start the
>>>>> application.
>>>>>
>>>>> However, for the flicker problem,yes , it still exists. But I think it
>>>>> is less obvious then custom AndroidStyle only. I need to be focused on
>>>>> screen change to discover the flicker.
>>>>>
>>>>> From my understanding, the splash screen change process can be divided
>>>>> into 3 steps:
>>>>>
>>>>> 1. Render window background and title bar according to theme.
>>>>>
>>>>> 2. QtActivity.onCreate(Bundle)
>>>>>
>>>>> If android.app.splash_screen_drawable is set, it will render the
>>>>> drawable. Otherwise, it will clear window background to #ff000000.
>>>>>
>>>>> 3. QQmlEngine loads the first scene and start rendering.
>>>>>
>>>>> If your don't set android.app.splash_screen_drawable, both of step 2
>>>>> and 3 will first render a black screen, but their timing are different.
>>>>> Step 3 is short and less obvious.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On 1 November 2015 at 20:36, Liang Jian <jianliang79 at gmail.com> wrote:
>>>>>
>>>>>>     To Ben Lau: I have tried this method in the past, but that will
>>>>>> also cause the flicker issue, and the most important is: with this method,
>>>>>> It will take very long time before the splash screen show up after I click
>>>>>> to start the app.
>>>>>>
>>>>>> On Sun, Nov 1, 2015 at 2:25 PM, Ben Lau <xbenlau at gmail.com> wrote:
>>>>>>
>>>>>>>
>>>>>>> I have a suggestion. Based on the method from Liang Jian. Add the
>>>>>>> following line to AndroidManifest.xml:
>>>>>>>
>>>>>>>             <meta-data android:name="android.app.splash_screen_drawable" android:resource="@drawable/icon"/>
>>>>>>>
>>>>>>>
>>>>>>> The "android:resource" should point to the same file like your
>>>>>>> MyAndroidStyle.
>>>>>>>
>>>>>>> Will that fix the problem?
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On 1 November 2015 at 09:40, Liang Jian <jianliang79 at gmail.com>
>>>>>>> wrote:
>>>>>>>
>>>>>>>>     I think we have encountered the same problem, the flicker I
>>>>>>>> have mentioned is the black screen between splash screen and the first qml
>>>>>>>> page :-)
>>>>>>>>
>>>>>>>> On Fri, Oct 30, 2015 at 11:23 PM, Bruno Tezine <btezine at gmail.com>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> Hi Liang Jian,
>>>>>>>>> Thank you for your response.
>>>>>>>>> I already tried to use this approach. You complain about a
>>>>>>>>> flicker, but what about the black screen between the splash and the first
>>>>>>>>> qml page?
>>>>>>>>> I don't know if this happened with you, but under my tests, the
>>>>>>>>> splash screen appears ok, but then the screen goes black for a while until
>>>>>>>>> the main qml page is loaded.
>>>>>>>>> Does it happen with you?
>>>>>>>>> Kind regards,
>>>>>>>>>    Bruno.
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> 2015-10-30 12:11 GMT-02:00 Liang Jian <jianliang79 at gmail.com>:
>>>>>>>>>
>>>>>>>>>>      According to my experience, the best way to show splash
>>>>>>>>>> screen in qt-android is to use a custom android theme and set its
>>>>>>>>>> android:windowBackground. In this way the splash screen will show instantly
>>>>>>>>>> after you click to launch your app. But unfortunately there is an annoying
>>>>>>>>>> bug about this method, please refer to
>>>>>>>>>> https://bugreports.qt.io/browse/QTBUG-43558
>>>>>>>>>>
>>>>>>>>>> On Thu, Oct 29, 2015 at 9:06 PM, Bruno Tezine <btezine at gmail.com>
>>>>>>>>>> wrote:
>>>>>>>>>>
>>>>>>>>>>> Hi,
>>>>>>>>>>> How can I create a splash screen for Android using Qt (without
>>>>>>>>>>> widgets)?
>>>>>>>>>>> I don't know if it's possible. The idea is to present a splash
>>>>>>>>>>> screen(image) immediately while the first qml page is loading. No timers
>>>>>>>>>>> involved.
>>>>>>>>>>> I have read several samples, but none seems to fit. Let me
>>>>>>>>>>> explain:
>>>>>>>>>>>
>>>>>>>>>>> 1) http://doc.qt.io/qt-5/qtquick-window-example.html
>>>>>>>>>>> --This example uses a timer. It doesn't display a splash while
>>>>>>>>>>> the app is still loading the first screen.
>>>>>>>>>>>
>>>>>>>>>>> 2)
>>>>>>>>>>> http://stackoverflow.com/questions/5486789/how-do-i-make-a-splash-screen
>>>>>>>>>>> --It explains how to create splash screens using two approaches.
>>>>>>>>>>> One using an Activity and other using a theme style. The first approach
>>>>>>>>>>> uses a timer and delays the app load. The second quickly display a splash,
>>>>>>>>>>> but after it disappears, the screen goes black while loading the first qml
>>>>>>>>>>> page.
>>>>>>>>>>>
>>>>>>>>>>> Is it possible?
>>>>>>>>>>> Thank you,
>>>>>>>>>>>    Bruno.
>>>>>>>>>>>
>>>>>>>>>>> _______________________________________________
>>>>>>>>>>> Android-development mailing list
>>>>>>>>>>> Android-development at qt-project.org
>>>>>>>>>>> http://lists.qt-project.org/mailman/listinfo/android-development
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>> _______________________________________________
>>>>>>>> Android-development mailing list
>>>>>>>> Android-development at qt-project.org
>>>>>>>> http://lists.qt-project.org/mailman/listinfo/android-development
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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