Category Archives: Platforms and frameworks

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30
08
21
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Invokable constructor in QT

Posted by | QT |

In QT 5.15 I declare a class with an invokable constructor:

class TestClass : public QObject
{
    Q_OBJECT

public:

    Q_INVOKABLE TestClass(QString val) {}
};

Q_DECLARE_METATYPE(TestClass*)

register its type:

qRegisterMetaType<TestClass*>();
(more…)
25
08
21
 1 Comment

‘Invalid UTF-8 code encountered.’ close reason with QWebSocket

Posted by | QT |

I get close reason: ‘Invalid UTF-8 code encountered.’ (code=1007) with QWebSocket in the following scenario:

  • I connect to Binance stream wss://stream.binance.com:9443/stream with QWebSocket::open.
  • Successfully receive messages for some time period (a few hours).
  • Binance disconnects me when its servers load increases (because I have low-priority API) and I get close reason code=1000 that indicates a normal closure.
  • Try to reconnect multiple times by calling QWebSocket::open again, but Binance closes the connection with close reason ‘Invalid UTF-8 code encountered.’ (code=1007) that indicates that an endpoint is terminating the connection because it has received data within a message that was not consistent with the type of the message (e.g., non-UTF-8 [RFC3629] data within a text message).
  • Restart the application manually and connect successfully.

The difficulty of reproducing the bug is that Binance disconnects me rarely (once a day, for example) and experimentation with disconnecting the network cable from my machine does not have this effect, after I connect the cable back, QWebSocker reconnects successfully. When I disconnect the network cable I get Error: ‘Unknown error’ (code=-1), Close reason: ” (code=1000).

(more…)
19
06
21
 1 Comment

Built my QT app for Android with API level 30 (Android 11)

Posted by | Android, QT |

New Android App Bundle and target API level requirements in 2021:

Starting August 2021, new apps will be required to target API level 30 (Android 11) and use the Android App Bundle publishing format. Starting November 2021, all app updates will be required to target API level 30 (Android 11). Apps with a download size of more than 150 MB are now supported by Play Asset Delivery and Play Feature Delivery.

I updated the manifest manually as follows:

&lt;?xml version="1.0"?&gt;
&lt;manifest package="net.geographx.LinesGame" xmlns:android="http://schemas.android.com/apk/res/android" android:versionName="2.5.30" android:versionCode="161" android:installLocation="auto"&gt;
    &lt;uses-sdk android:minSdkVersion="21" android:targetSdkVersion="30"/&gt;
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22
05
21
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My QT Android app periodically crashes at android::RefBase::incStrong(void const*)

Posted by | Android, QT |

The call stack is:

  #00  pc 00000000000097a8  /system/lib/libutils.so (android::RefBase::incStrong(void const*) const+4)
  #00  pc 0000000000022145  /vendor/lib/libIMGegl.so
  #00  pc 000000000000ab79  /vendor/lib/libIMGegl.so (KEGLGetDrawableParameters+252)
  #00  pc 0000000000041c53  /vendor/lib/egl/libGLESv2_mtk.so
  #00  pc 000000000001663d  /vendor/lib/egl/libGLESv2_mtk.so
  #00  pc 0000000000016b01  /vendor/lib/egl/libGLESv2_mtk.so (glClear+440)
  #00  pc 000000000008acaf  /data/app/net.geographx.LinesGame-9_pUex92-tGEqE4iIbRCCw==/lib/arm/libLinesGameQt_armeabi-v7a.so (LinesGame::Squircle::beforeRendering()+270)
  #00  pc 000000000017d5b9  /data/app/net.geographx.LinesGame-9_pUex92-tGEqE4iIbRCCw==/lib/arm/libQt5Core_armeabi-v7a.so
  #00  pc 0000000000176f4d  /data/app/net.geographx.LinesGame-9_pUex92-tGEqE4iIbRCCw==/lib/arm/libQt5Quick_armeabi-v7a.so (QQuickWindowPrivate::renderSceneGraph(QSize const&amp;, QSize const&amp;)+172)

It is a QT bug that is not fixed yet.

Also my app crashes at the destructor of std::thread and this also a QT bug that is not fixed yet.

14
05
21
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Applying a path that fixes a bug in QT 5.15.2

Posted by | QT |

There was a bug in QT 5.15.2 that results in app crash on Android 5.1 and a patch:

Submodule qtbase contains modified content
diff --git a/qtbase/src/corelib/plugin/qlibrary_unix.cpp b/qtbase/src/corelib/plugin/qlibrary_unix.cpp
index a5c72f81d9..5cd21b67a4 100644
--- a/qtbase/src/corelib/plugin/qlibrary_unix.cpp
+++ b/qtbase/src/corelib/plugin/qlibrary_unix.cpp
@@ -243,10 +243,10 @@ bool QLibraryPrivate::load_sys()
             }
             if (hnd) {
                 using JniOnLoadPtr = jint (*)(JavaVM *vm, void *reserved);
-                JniOnLoadPtr jniOnLoad = reinterpret_cast&lt;JniOnLoadPtr&gt;(dlsym(pHnd, "JNI_OnLoad"));
+                JniOnLoadPtr jniOnLoad = reinterpret_cast&lt;JniOnLoadPtr&gt;(dlsym(hnd, "JNI_OnLoad"));
                 if (jniOnLoad &amp;&amp; jniOnLoad(QtAndroidPrivate::javaVM(), nullptr) == JNI_ERR) {
                     dlclose(hnd);
-                    pHnd = nullptr;
+                    hnd = nullptr;
                 }
             }
 #endif

Looks like it was simply a typo and pHnd was replaced with hnd.

QT 5.15.3 where the bug was fixed is commercial so I applied the patch by myself (thanks to danilabagroff from stackoverflow.com):

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12
05
21
 1 Comment

Building QT 6.1.0 for Android on Windows

Posted by | Android, QT |

Theoretically it can be:

git clone --recursive https://code.qt.io/qt/qt5.git --branch v6.1.0

or alternatively:

git clone https://code.qt.io/qt/qt5.git --branch v6.1.0
./init-repository --branch --module-subset=essential,qtandroidextras,qtsvg,qtquickcontrols2,qtgraphicaleffects,qtwebsockets,qtmultimedia

or

./init-repository --module-subset=all
(more…)
12
05
21
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QT 5.15.2 app crashes on Android 5.1

Posted by | Android, QT |

My QT 5.15.2 app crashes on Android 5.1 with the following call stack:

*** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
Build fingerprint: 'Android/sdk_google_phone_x86_64/generic_x86_64:5.1.1/LMY48X/6402608:userdebug/test-keys'
Revision: '0'
ABI: 'x86_64'
pid: 3954, tid: 3998, name: qtMainLoopThrea  &gt;&gt;&gt; net.geographx.LinesGame &lt;&lt;&lt;
signal 6 (SIGABRT), code -6 (SI_TKILL), fault addr --------
Abort message: 'art/runtime/mirror/art_method.cc:356] Check failed: !IsFastNative() int java.lang.Character.digitImpl!(int, int)'
    rax 0000000000000000  rbx 0000000000000f9e  rcx ffffffffffffffff  rdx 0000000000000006
    rsi 0000000000000f9e  rdi 0000000000000f72
    r8  0000000000000022  r9  0000000000000002  r10 0000000000000008  r11 0000000000000206
    r12 000000000000000b  r13 0000000000000006  r14 00007f747b51a000  r15 0000000000000051
    cs  0000000000000033  ss  000000000000002b
    rip 00007f7488099e37  rbp 00007f7467007b70  rsp 00007f74670063e8  eflags 0000000000000206
(more…)
11
12
20
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Dragging a link from a browser to a QML app

Posted by | QML, QT |

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);
        }
(more…)
27
07
20
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Publishing QT application in Apple App Store

Posted by | iOS, Mac OS X, QT |

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.

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05
06
20
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Compiling QT5.15.0 with OpenSSL support with MSVC2017 on Windows

Posted by | QT, Win32 | Tagged |

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=%PERL_ROOT%;%PATH%
set PATH=%PATH%;C:\PFiles\nasm-2.14.02-win64
perl Configure VC-WIN64A
set CL=/MP
nmake
nmake install
(more…)
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