Qt5 QGeoPositionInfoSource::createDefaultSource() crashes on Android 5.0

Question

I'm developing a Qt5 application for Android (with CMake!) and currently I'm trying to read location data using Qt's QGeoPositionInfoSource. All of my application is doing fine so far but when I run

auto source = QGeoPositionInfoSource::createDefaultSource(this);

The application crashes immediately and logcat gives me:

I/__log_qt(  422): (II) dpw_qt5:    <last output from my app>
F/libc    (  422): Fatal signal 11 (SIGSEGV), code 1, fault addr 0x0 in tid 797 (QtThread)
I/DEBUG   (  333): *** *** *** *** *** *** *** *** *** *** *** *** *** *** *** ***
I/DEBUG   (  333): Build fingerprint: 'samsung/trltexx/trlte:5.0.1/LRX22C/N910FXXU1BOE3:user/release-keys'
I/DEBUG   (  333): Revision: '12'
I/DEBUG   (  333): ABI: 'arm'
I/DEBUG   (  333): pid: 422, tid: 797, name: QtThread  >>> org.qtproject.DPW <<<
I/DEBUG   (  333): signal 11 (SIGSEGV), code 1 (SEGV_MAPERR), fault addr 0x0
I/DEBUG   (  333):     r0 00000000  r1 9d2bedf8  r2 00010006  r3 be7eb61d
I/DEBUG   (  333):     r4 9d2bedf4  r5 9d2bedf8  r6 00000000  r7 9cffa030
I/DEBUG   (  333):     r8 9d2bedf4  r9 afd04388  sl 00000001  fp 9d2bf8dc
I/DEBUG   (  333):     ip 9cff9e80  sp 9d2bedd0  lr 9cff49b7  pc 9cff612e  cpsr 60070030
I/DEBUG   (  333): 
I/DEBUG   (  333): backtrace:
I/DEBUG   (  333):     #00 pc 0000512e  /data/data/org.qtproject.DPW/qt-reserved-files/plugins/position/libqtposition_android.so
I/DEBUG   (  333):     #01 pc 000039b3  /data/data/org.qtproject.DPW/qt-reserved-files/plugins/position/libqtposition_android.so

I've used the last three Android NDKs and several versions of Qt from 5.6 to 5.9 - all with the same result so I think I'm doing something wrong systematically.

My AndroidManifest.xml contains the following lines:

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />

Do you have any idea for me where I can start to investigate?

Update:

I've been tracing back the top most line of the call stack:

I/DEBUG   (  333):     #00 pc 0000512e  /data/data/org.qtproject.DPW

and I found out that the following line inside jnipositioning.cpp causes the crash:

if (javaVM->GetEnv((void**)&jniEnv, JNI_VERSION_1_6) < 0) {

so the new question is: what can make javavm->GetEnv() (declared in jni.h) crash?

Another Update:

jpo38 pointed out that that building with qmake results in an Android app that does not crash. I've set up a github project demonstrating this behavior.

So the question is now: What's the difference between the apps being configured with CMake and qmake?

Answer 1

This apparently works pretty well:

TestGeo.pro:

QT += core gui
QT += positioning
QT += widgets

TARGET = TestGeo
TEMPLATE = app

SOURCES += main.cpp

CONFIG += mobility
MOBILITY = 

main.cpp:

#include <QMainWindow>
#include <QApplication>

#include <QGeoPositionInfoSource>
#include <QDebug>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QMainWindow w;

    qDebug() << "Creating";
    auto source = QGeoPositionInfoSource::createDefaultSource(&a);
    if ( source )
        qDebug() << "Created";
    else
        qDebug() << "NULL";

    w.show();

    return a.exec();
}

Program outputs with no crash:

Creating
Created

Note that I added no AndroidManifest.xml file to the project. It works both with "Localisation" enabled or disabled.

I'm deploying with Android-22 target on Nexus 6 with Android 5.1 (armeabi-v7a). Using Qt 5.6 (GCC 4.9). Using NDK r11b.

There must be something wrong with your setup.

So do this setup, generate the working apk. Then extract the content of this working apk and your failing apk. By checking the differences (missing libraries, files, different manifest....), you may identify what's wrong with your CMake build and deployment environment and later fix it (possibly by manually copying missing files in the CMake project)!

In your case the references to Qt's positioning libraries are missing. Just add them correctly to your AndroidManifest.xml:

<meta-data android:name="android.app.load_local_libs" android:value="plugins/platforms/android/libqtforandroid.so:plugins/position/libqtposition_android.so"/>
<meta-data android:name="android.app.load_local_jars" android:value="jar/QtAndroid.jar:jar/QtAndroidAccessibility.jar:jar/QtAndroid-bundled.jar:jar/QtAndroidAccessibility-bundled.jar:jar/QtPositioning.jar:jar/QtPositioning-bundled.jar"/>
<meta-data android:name="android.app.static_init_classes" android:value="org.qtproject.qt5.android.positioning.QtPositioning:org.qtproject.qt5.android.positioning.QtPositioning"/>