QtNotes

Passing android Intents to Qt (Pass parameters between intents)

Working on QField I had the necessity of passing values from the QtActivity.java to the Qt cpp world, here how I did it using an Intent that is sent to the QtActivity (the one you should not edit that comes with Qt). For much more information see this post series.

hopefully this will be helpful to someone.

Start QtActivity

private void startQtActivity() {
	String dotqgis2_dir = "Test dotqgis2_dir";
	String share_dir = "Test share_dir";
	// forward to startQtActivity and finish QFieldActivity
	Intent intent = new Intent();
	intent.setClass(QFieldActivity.this, QtActivity.class);
	intent.putExtra("DOTQGIS2_DIR", dotqgis2_dir);
        intent.putExtra("SHARE_DIR", share_dir);
	startActivity(intent);
	finish();
}

#include <QAndroidJniObject>
#include <QtAndroid>
#include <QDebug>
#ifdef Q_OS_ANDROID
QString getExtra(QAndroidJniObject extras, QString extra){
    if(extras.isValid()){
        QAndroidJniObject extra_jni = QAndroidJniObject::fromString(extra);
        extra_jni = extras.callObjectMethod("getString", "(Ljava/lang/String;)Ljava/lang/String;", extra_jni.object<jstring>());
        if (extra_jni.isValid()){
            extra = extra_jni.toString();
            qDebug() << extra;
            return extra;
        }
    }
    return "";
}
void getIntentExtras(QStringList intentExtras)
{
    QAndroidJniObject activity = QtAndroid::androidActivity();
    if (activity.isValid()) {
        qDebug() << "activity";
        QAndroidJniObject intent = activity.callObjectMethod("getIntent", "()Landroid/content/Intent;");
        if (intent.isValid()) {
            qDebug() << "intent: " << intent.toString();
            QAndroidJniObject extras = intent.callObjectMethod("getExtras", "()Landroid/os/Bundle;");
            qDebug() << "extras: " << extras.toString();
            QString extra;
            for (int i = 0; i < intentExtras.size(); ++i){
                extra = intentExtras.at(i).toLocal8Bit().constData();
                getExtra(extras, extra);
            }
          }
        }
}
QStringList intentExtras;
intentExtras << "DOTQGIS2_DIR" << "SHARE_DIR";
getIntentExtras(intentExtras);
#endif

This is the first version of the cpp code that I wrote, just for reference. The below code is much cleaner.

#include <QAndroidJniObject>
#include <QtAndroid>
#include <QDebug>
void getIntent()
{
#ifdef Q_OS_ANDROID
    QAndroidJniObject activity = QtAndroid::androidActivity();
    if (activity.isValid()) {
        qDebug() << "activity";
        QAndroidJniObject intent = activity.callObjectMethod("getIntent", "()Landroid/content/Intent;");
        if (intent.isValid()) {
            qDebug() << "intent: " << intent.toString();
            QAndroidJniObject extras = intent.callObjectMethod("getExtras", "()Landroid/os/Bundle;");
            if(extras.isValid()){
                qDebug() << "extras: " << extras.toString();
                QAndroidJniObject dotqgis2_dir = QAndroidJniObject::fromString("DOTQGIS2_DIR");
                QAndroidJniObject share_dir = QAndroidJniObject::fromString("SHARE_DIR");
                dotqgis2_dir = extras.callObjectMethod("getString", "(Ljava/lang/String;)Ljava/lang/String;", dotqgis2_dir.object<jstring>());
                share_dir = extras.callObjectMethod("getString", "(Ljava/lang/String;)Ljava/lang/String;", share_dir.object<jstring>());
                if (dotqgis2_dir.isValid()){
                    qDebug() << dotqgis2_dir.toString();
                }
                if (share_dir.isValid()){
                    qDebug() << share_dir.toString();
                }
            }
          }
        }
#endif
}

source

Passing android Intents to Qt (Pass parameters between intents)

Start QtActivity