Category Archives: Platforms and frameworks

Dragging a link from a browser to a QML app

When a link is dragged from a browser on Window 10 platform it contains the page title, but they did not make it accessible in QML:

import QtQuick 2.15
import QtQuick.Controls 2.15

ApplicationWindow {
    visible: true
    width: 640
    height: 480
    title: qsTr("Scroll")
    id: root

    DropArea {
        id: dropArea;
        anchors.fill: parent
        onEntered: {
            root.color = "gray";
            drag.accept (Qt.LinkAction);

Publishing QT application in Apple App Store

I succeeded with building my app for iOS and my first step in publishing the app in App Store was opening generated .xcodeproj file in XCode, but XCode froze displaying rotating progress indicator and wait cursor.


Compiling QT5.15.0 with OpenSSL support with MSVC2017 on Windows

First, I compiled and installed OpenSSL 1.1.1g in the same way as before:

set PERL_ROOT=E:\PFiles\Strawberry\perl\bin
set PATH=%PATH%;C:\PFiles\nasm-2.14.02-win64
perl Configure VC-WIN64A
set CL=/MP
nmake install

Building QT 5.15.0 (everywhere) for Android on Windows

  • Install Android Studio with SDK and NDK API Level 28.
  • Install strawberry-perl- first (before mingw-w64-install.exe) to E:\PFiles
  • Install MinGW with mingw-w64-install.exe online installer. Select POSIX threads in the installer UI combobox, otherwise you will get:
  • Extract the sources from QT archive to E:\Qt\Qt5.15.0 and run the following script in QT root directory containing configure.bat:

Running a QT app on MacOS

I was able to compile and debug my app on MacOS with QT Creator:

All C++ code compiled successfully, but something went wrong with OpenGLES shaders. It is probably because I included OpenGLES headers from a wrong place.


QT app is deactivated incorrectly on Android 10 in Gesture mode

If I enable Gesture mode on an Android 10 emulator by tapping System->Gestures->System Navigation->Gesture Navigation and then deactivate my app by swiping and reactivate it back, I get the following in the log:

adb logcat | grep "\ Lines"
05-04 21:52:36.389 11794 11939 D Lines   : Squircle::aboutToQuit()
05-04 21:52:36.389 11794 11939 D Lines   : InterstitialAdWrapper clear() called.
05-04 21:52:36.392 11794 11939 D Lines   : InterstitialAdWrapper InterstitialAd destructor called.
05-04 21:52:36.393 11794 11939 D Lines   : Squircle destructor called.
05-04 21:52:36.396 11794 11939 W Lines   : exit app 0
05-04 21:52:37.032 11794 11939 D Lines   : OslSoundPool destructor
05-04 21:52:37.117  2040  2134 W InputDispatcher: channel '8474831 net.geographx.LinesGame/net.geographx.MainActivity (server)' ~ Consumer closed input channel or an error occurred.  events=0x9
05-04 21:52:37.117  2040  2134 E InputDispatcher: channel '8474831 net.geographx.LinesGame/net.geographx.MainActivity (server)' ~ Channel is unrecoverably broken and will be disposed!
05-04 21:52:37.123  2040  3120 I WindowManager: WIN DEATH: Window{8474831 u0 net.geographx.LinesGame/net.geographx.MainActivity}
05-04 21:52:37.123  2040  3120 W InputDispatcher: Attempted to unregister already unregistered input channel '8474831 net.geographx.LinesGame/net.geographx.MainActivity (server)'
05-04 21:52:37.136  2040  3120 W ActivityManager: Scheduling restart of crashed service net.geographx.LinesGame/ in 1000ms
05-04 21:52:37.151  2040  2057 I ActivityManager: Process net.geographx.LinesGame (pid 11794) has died: cch CRE
05-04 21:52:38.034  2040  2057 I ActivityTaskManager: START u0 {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10200000 cmp=net.geographx.LinesGame/net.geographx.MainActivity bnds=[37,882][238,1191]} from uid 10090
05-04 21:52:38.055  2040  2057 I chatty  : uid=1000(system) Binder:2040_2 identical 8 lines
05-04 21:52:38.099  2040  2072 I ActivityManager: Start proc 12702:net.geographx.LinesGame/u0a134 for activity {net.geographx.LinesGame/net.geographx.MainActivity}
05-04 21:52:38.101 12702 12702 W raphx.LinesGam: Unexpected CPU variant for X86 using defaults: x86
05-04 21:52:38.124 12702 12702 E raphx.LinesGam: Not starting debugger since process cannot load the jdwp agent.
05-04 21:52:38.966  2040  2069 I ActivityTaskManager: Displayed net.geographx.LinesGame/net.geographx.MainActivity: +931ms
05-04 21:52:39.062 12702 12826 D Translation file has been loaded successfully:  "LinesGame_en"
05-04 21:52:39.062 12702 12826 D Lines   : App version:  "2.5.11, #133"
05-04 21:52:39.072 12702 12826 D Lines   : QT/SysInfo: Device Pixel Ratio: 3  Screen DPI:  147.131
05-04 21:52:39.106 12702 12826 D Lines   : InterstitialAdWrapper  valid
05-04 21:52:39.185 12702 12826 D Lines   : qml: Registering adfree
05-04 21:52:39.189  7632  9145 W Finsky  : [672] gcs.d(23): net.geographx.LinesGame: No account found.
05-04 21:52:39.411 12702 12826 D Lines   : qml: adfree Component.onCompleted
05-04 21:52:39.413 12702 12826 D Lines   : InterstitialAdWrapper: calling Java method ' initializeInterstitialAd ' from C++
05-04 21:52:39.413 12702 12826 D Lines   : Starting the application event loop...
05-04 21:52:39.463 12702 12826 D Lines   : onApplicationStateChanged(Qt::ApplicationActive)

Packaging QT application into Android App Bundle (AAB)

In Qt Creator 4.11.0 on Projects page check “Build .aab”:

This will create .aab file.


My Android QT app crashes at qt_qFindChild_helper.

I have an Android QT app with more than has 14K active users at the moment of writing this post. The app is relatively stable, its crash rate is 0.34%:


Adding interstitial ads to a QT application on Android platform

I keep working on my Lines Game and probably I try to make it the best Lines Game in the world, but there is some disappointing incident that prevents it from being the best and makes it a usual game that glitches a bit. To see the glitch in action download the beta version of the game.

Adding Interstitial Ads to a QT application on Android platform is an interesting and relatively exciting job. I learned the following facts while doing it:

  1. To build my app with Google Play Services I add dependency to build.gradle and add and to the manifest.
  2. I do not specify additional permissions (uses-permission attributes INTERNET, WRITE_EXTERNAL_STORAGE, ACCESS_NETWORK_STATE) required by ads, but they are detected automatically when I upload the app to Google Play store and the used is not prompted to allow them when the app starts.
  3. QT main thread (on which QML UI is run) is not Android UI thread. So I cannot call Java advertising API from QML or C++ directly, but all the calls should be queued with runOnUiThread method.
  4. To access Context required by Java advertising API I replace QtActivity with my own custom activity that implements all the advertising logic and forwards all the lifecycle events to original QtActivity.
  5. When the interstitial ad is open my activity is paused and stopped (onPaused / onStopped event handlers are called in Java and onApplicationStateChanged with Qt::ApplicationInactive / Qt::ApplicationSuspended respectively ) and when the interstitial ad is closed my activity is resumed but in different ways either with onRestart.

Compiling OpenSSL 1.1 with MSVC2017 for using with QT 5.13

QT does not work with OpenSSL 1.0 anymore. Versions QT 5.12.4 and above require OpenSSL 1.1, but fortunately OpenSSL 1.1 can be easily compiled with MS2017 as follows:

set PATH=%PATH%;C:\Perl64\bin
set PATH=%PATH%;C:\PFiles\nasm-2.14.02-win64
perl Configure VC-WIN64A

The key to the success is using ‘VS2017 x64 Native Tools Command Prompt‘, but not ‘VS2017 Developer Command Prompt’.

To make QT use OpenSSL, two dlls


should be copied to QT binary directory, for example, C:\Qt\Qt5.13.0\5.13.0\msvc2017_64\bin