Qt for android 获取USB设备列表（二）JNI方式获取

news2024/9/23 5:25:29

简介

基于上篇 [Qt for android 获取USB设备列表（一）Java方式获取]，这篇就纯粹多了，直接将上篇代码转换成JNI方式即可。即所有的设备连接与上篇一致。 (https://listentome.blog.csdn.net/article/details/139205850)

关键代码

void MainWindow::getDeviceList()
{
    QJniObject usbService = QJniObject::getStaticObjectField("android/content/Context",
                                                            "USB_SERVICE",
                                                            "Ljava/lang/String;");
    if (!usbService.isValid())
    {
        logger("fail to get usb service");
        return;
    }


    QJniObject activity = QJniObject(QNativeInterface::QAndroidApplication::context());

    QJniObject usbManager = activity.callObjectMethod("getSystemService",
                                                      "(Ljava/lang/String;)Ljava/lang/Object;",
                                                      usbService.object<jstring>());
    if (!usbManager.isValid())
    {
        logger("fail to get usb manager");
        return;
    }

    QJniObject usbDeviceListHashMap = usbManager.callObjectMethod("getDeviceList",
                                                           "()Ljava/util/HashMap;");
    QJniObject devListKeySet = usbDeviceListHashMap.callObjectMethod("keySet",
                                                       "()Ljava/util/Set;");
    QJniObject devListIter = devListKeySet.callObjectMethod("iterator",
                                                       "()Ljava/util/Iterator;");
    jint devListSize = usbDeviceListHashMap.callMethod<jint>("size", "()I");

    QJniObject usbDevObj;
    QJniObject usbDevObjIter;
    int vid = 0, pid = 0;
    QString devName;
    for (int i = 0; i < devListSize; ++i)
    {
        usbDevObjIter = devListIter.callObjectMethod("next",
                                            "()Ljava/lang/Object;");
        usbDevObj = usbDeviceListHashMap.callObjectMethod("get",
                                                   "(Ljava/lang/Object;)Ljava/lang/Object;",
                                                   usbDevObjIter.object());
        vid = usbDevObj.callMethod<jint>("getVendorId", "()I");
        pid = usbDevObj.callMethod<jint>("getProductId", "()I");
        devName = usbDevObj.callMethod<jstring>("getDeviceName", "()Ljava/lang/String;").toString();

        logger(QString("Name: %1, VID: %2, PID: %3").arg(devName).arg(vid).arg(pid));
    }

}