Call Java method from c++

[mrdebug]

Hi I need to call from c++ this java method:

    public String GetScanResultAt(int count) {
        return "123";
    }

I'm using this to call a java method without arguments that returs a string:

qDebug() << QAndroidJniObject(QtAndroid::androidActivity().callObjectMethod<jstring>("GetScanResultAt")).toString();

Which is the right way to change the line of code above to pass a int parameter?

[KroMignon]

@mrdebug said in Call Java method from c++:

Which is the right way to change the line of code above to pass a int parameter?

You have to add function signature:

qDebug() << QAndroidJniObject(QtAndroid::androidActivity().callObjectMethod<jstring>("GetScanResultAt", "(I)Ljava/lang/String;", jint(55)).toString();

[mrdebug]

Below examples on how to use java methods with arguments

Java

    public int Test01() {
        System.out.println("Test01");
        return 0;
    }
    public int Test02(int Value) {
        System.out.println("Test02");
        System.out.println(Value);
        return 0;
    }
    public int Test03(String Value) {
        System.out.println("Test03");
        System.out.println(Value);
        return 0;
    }
    public String Test04(int Value) {
        System.out.println("Test04");
        System.out.println(Value);
        return "Hello!!!";
    }
    public String Test04b(String Value) {
        System.out.println("Test04b");
        System.out.println(Value);
        return "Hello!!!";
    }
    public String[] Test05(String Value1, String Value2) {
        System.out.println("Test05");
        System.out.println(Value1);
        System.out.println(Value2);
        String[] Result= new String[2];
        Result[0]= "Hello";
        Result[1]= "world!!!";
        return Result;
    }

Qt / C++

    qDebug() << "Test01 result:" << QtAndroid::androidActivity().callMethod<jint>("Test01");
    qDebug() << "Test02 result:" << QtAndroid::androidActivity().callMethod<jint>("Test02", "(I)I", 10);


    QAndroidJniObject Value1= QAndroidJniObject::fromString("Value1");
    QAndroidJniObject Value2= QAndroidJniObject::fromString("Value2");

    qDebug() << "Test03 result:" << QtAndroid::androidActivity().callMethod<jint>("Test03", "(Ljava/lang/String;)I", Value1.object<jstring>());
    qDebug() << "Test04 result:" << QAndroidJniObject(QtAndroid::androidActivity().callObjectMethod("Test04", "(I)Ljava/lang/String;", 123456)).toString();
    qDebug() << "Test04b result:" << QAndroidJniObject(QtAndroid::androidActivity().callObjectMethod("Test04b", "(Ljava/lang/String;)Ljava/lang/String;", Value1.object<jstring>())).toString();

    QAndroidJniObject stringArray= QtAndroid::androidActivity().callObjectMethod("Test05",
                                                                                "(Ljava/lang/String;Ljava/lang/String;)[Ljava/lang/String;",
                                                                                Value1.object<jstring>(),
                                                                                Value2.object<jstring>());

    if (stringArray.isValid()) {
        jobjectArray objectArray= stringArray.object<jobjectArray>();
        for (int count= 0; count< env->GetArrayLength(objectArray); count++) {
            QAndroidJniObject AndroidJniObject= env->GetObjectArrayElement(objectArray, count);
            qDebug() << AndroidJniObject.toString();
        }
    }