Android JNI, display AlertDialog for LOCATION permissions

[Bongani]

I want to show an AlertDialog on my android App to request "Location" permission since it's compulsory from Android API 26. I am using JNI to call a Java function that will prompt the trigger the AlertDialog.

below is my Java code

    public static void init(String node){
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if (m_instance.checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                final AlertDialog.Builder builder = new AlertDialog.Builder(m_instance);
                builder.setTitle("This app needs location access");
                builder.setMessage("Please grant location access so this app can detect beacons.");
                builder.setPositiveButton(android.R.string.ok, null);
                builder.setOnDismissListener(new DialogInterface.OnDismissListener() {
                    @Override
                    public void onDismiss(DialogInterface dialog) {
                        m_instance.requestPermissions(new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, PERMISSION_REQUEST_COARSE_LOCATION);
                    }
                });
                builder.show();
            }
        }
}

And this is how i am calling it from my C++ code.

    QAndroidJniObject javaNotification = QAndroidJniObject::fromString("beconNode");
    QAndroidJniObject::callStaticMethod<void>("org/qtproject/example/beacorat/Scan",
                                              "init",
                                              "(Ljava/lang/String;)V",
                                              javaNotification.object<jstring>());

I am receiving the below error when trying to call the function.

F art     : art/runtime/java_vm_ext.cc:410] JNI DETECTED ERROR IN APPLICATION: JNI GetStaticMethodID called with pending exception java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
F art     : art/runtime/java_vm_ext.cc:410]   at void android.os.Handler.<init>(android.os.Handler$Callback, boolean) (Handler.java:200)
F art     : art/runtime/java_vm_ext.cc:410]   at void android.os.Handler.<init>() (Handler.java:114)
F art     : art/runtime/java_vm_ext.cc:410]   at void android.app.Dialog.<init>(android.content.Context, int, boolean) (Dialog.java:152)
F art     : art/runtime/java_vm_ext.cc:410]   at void android.app.AlertDialog.<init>(android.content.Context, int, boolean) (AlertDialog.java:202)
F art     : art/runtime/java_vm_ext.cc:410]   at android.app.AlertDialog android.app.AlertDialog$Builder.create() (AlertDialog.java:1105)
F art     : art/runtime/java_vm_ext.cc:410]   at android.app.AlertDialog android.app.AlertDialog$Builder.show() (AlertDialog.java:1150)
F art     : art/runtime/java_vm_ext.cc:410]   at void org.qtproject.example.beacorat.Scan.initBT() (Scan.java:54)
F art     : art/runtime/java_vm_ext.cc:410]   at void org.qtproject.example.beacorat.Scan.startLeScan(java.lang.String) (Scan.java:74)

This crashes the whole App.

Please help.

[J.Hilk]

@Bongani

I'm not very good with java, a reason why I'm very grateful for the QtAndroid modul.

you can use that one for runtime permission request/check

http://doc.qt.io/qt-5/qtandroid.html#requestPermissions

This should help you.