Short answer – pretty simple. Thanks to QtAndroidExtras

First we need to add to your .pro file:

android: QT += androidextras

then add simple class to your codebase. Header:

#ifndef VIBRATOR_H
#define VIBRATOR_H

#include <QObject>

#if defined(Q_OS_ANDROID)
#include <QAndroidJniEnvironment>
#include <QAndroidJniObject>
#endif
class Vibrator : public QObject
{
    Q_OBJECT
public:
    explicit Vibrator(QObject *parent = 0);
signals:
public slots:
    void vibrate(int milliseconds);
private:
#if defined(Q_OS_ANDROID)
    QAndroidJniObject vibratorService;
#endif
};

#endif // VIBRATOR_H

and the code:

#include "vibrator.h"
#include <QDebug>

Vibrator::Vibrator(QObject *parent) : QObject(parent)
{
#if defined(Q_OS_ANDROID)
    QAndroidJniObject vibroString = QAndroidJniObject::fromString("vibrator");
    QAndroidJniObject activity = QAndroidJniObject::callStaticObjectMethod("org/qtproject/qt5/android/QtNative", "activity", "()Landroid/app/Activity;");
    QAndroidJniObject appctx = activity.callObjectMethod("getApplicationContext","()Landroid/content/Context;");
    vibratorService = appctx.callObjectMethod("getSystemService", "(Ljava/lang/String;)Ljava/lang/Object;", vibroString.object<jstring>());
#endif
}

#if defined(Q_OS_ANDROID)

void Vibrator::vibrate(int milliseconds) {
    if (vibratorService.isValid()) {
        jlong ms = milliseconds;
        jboolean hasvibro = vibratorService.callMethod<jboolean>("hasVibrator", "()Z");
        vibratorService.callMethod<void>("vibrate", "(J)V", ms);
    } else {
        qDebug() << "No vibrator service available";
    }
}

#else
void Vibrator::vibrate(int milliseconds) {
    Q_UNUSED(milliseconds);
}

#endif

now you have to expose the class to QML:

#include "vibrator.h"
...
Vibrator vibrator;
engine.rootContext()->setContextProperty("Vibrator", &vibrator);

voila! its ready to use!

Vibrator.vibrate(500)

Enjoy