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// Copyright (C) 2026 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#include <QApplication>
#include <QJsonObject>
#include <QLabel>
#include <QPointer>
#include <QPushButton>
#include <QString>
#include <QVBoxLayout>
#include <QWidget>
#include <QtCore/qharmonyappjscontext.h>
#include <QtCore/qharmonyjscontext.h>
#include <QtCore/qharmonyjsonconversions.h>
#include <functional>
#include <napi.h>
using QHarmonyApplication = QNativeInterface::QHarmonyApplication;
namespace {
const QString wantParametersPropName = QStringLiteral("parameters");
const QString restartCountWantParamName = QStringLiteral("org.qtproject.example.restartCount");
//! [2]
void showStatusInLabel(QPointer<QLabel> statusLabel, QString text)
{
QHarmonyApplication::runOnQtThread(
[statusLabel, text]() {
if (statusLabel)
statusLabel->setText(text);
});
}
void showFailureInLabel(QPointer<QLabel> statusLabel, const QString &errorText)
{
showStatusInLabel(statusLabel, QStringLiteral("Failed to restart application: %1").arg(errorText));
}
//! [2]
//! [0]
void restartApplicationWithWant(QHarmonyAppJsContext &appJsContext, Napi::Object want, QPointer<QLabel> statusLabel)
{
Napi::Env env(appJsContext.env());
Napi::Object ability(env, appJsContext.defaultAbility());
if (ability.IsEmpty()) {
showFailureInLabel(statusLabel, QStringLiteral("no ability to restart from"));
return;
}
try {
auto abilityContext = ability.Get("context").As<Napi::Object>();
auto getApplicationContext = abilityContext.Get("getApplicationContext").As<Napi::Function>();
auto applicationContext = getApplicationContext.Call(abilityContext, {}).As<Napi::Object>();
auto restartAppFunc = applicationContext.Get("restartApp").As<Napi::Function>();
restartAppFunc.Call(applicationContext, {want});
} catch (const Napi::Error &error) {
showFailureInLabel(statusLabel, QString::fromUtf8(error.what()));
}
}
//! [0]
Napi::Object appLaunchWant(QHarmonyAppJsContext &appJsContext)
{
Napi::Env env(appJsContext.env());
Napi::Object ability(env, appJsContext.defaultAbility());
if (ability.IsEmpty())
return Napi::Object();
return ability.Get("launchWant").As<Napi::Object>();
}
QJsonObject readLaunchWant()
{
return QHarmonyApplication::runOnJsThreadAndWait(
[](QHarmonyJsContext &jsContext) {
auto &appJsContext = QHarmonyAppJsContext::fromJsContext(jsContext);
return QtHarmony::mapJsObjectToQJsonObject(appJsContext.env(), appLaunchWant(appJsContext));
});
}
QWidget *createActionButton(const QString &label, QWidget *parent, std::function<void()> action)
{
auto *button = new QPushButton(label, parent);
QObject::connect(button, &QPushButton::clicked, parent, std::move(action));
return button;
}
int restartCountFromWant(const QJsonObject &want)
{
return want.value(wantParametersPropName).toObject().value(restartCountWantParamName).toInt();
}
QJsonObject makeWantWithRestartCount(const QJsonObject &launchWant, int restartCount)
{
QJsonObject parameters = launchWant.value(wantParametersPropName).toObject();
parameters.insert(restartCountWantParamName, restartCount);
QJsonObject want = launchWant;
want.insert(wantParametersPropName, parameters);
return want;
}
}
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
const QJsonObject launchWant = readLaunchWant();
const int restartCount = restartCountFromWant(launchWant);
QWidget window;
window.setWindowTitle(QStringLiteral("Restart application example"));
auto *statusLabel = new QLabel(&window);
statusLabel->setWordWrap(true);
auto *layout = new QVBoxLayout(&window);
//! [1]
layout->addWidget(
createActionButton(
QStringLiteral("Restart with the launch Want\n(the restart count stays the same)"),
&window,
[statusLabel]() {
statusLabel->clear();
QHarmonyApplication::runOnJsThread(
[statusLabel = QPointer<QLabel>(statusLabel)](QHarmonyJsContext &jsContext) {
auto &appJsContext = QHarmonyAppJsContext::fromJsContext(jsContext);
restartApplicationWithWant(appJsContext, appLaunchWant(appJsContext), statusLabel);
});
}));
layout->addWidget(
createActionButton(
QStringLiteral("Restart with the restart count increased"),
&window,
[statusLabel, want = makeWantWithRestartCount(launchWant, restartCount + 1)]() {
statusLabel->clear();
QHarmonyApplication::runOnJsThread(
[want, statusLabel = QPointer<QLabel>(statusLabel)](QHarmonyJsContext &jsContext) {
auto &appJsContext = QHarmonyAppJsContext::fromJsContext(jsContext);
Napi::Object jsWant(appJsContext.env(), QtHarmony::mapQJsonObjectToJsObject(appJsContext.env(), want));
restartApplicationWithWant(appJsContext, jsWant, statusLabel);
});
}));
//! [1]
layout->addWidget(new QLabel(QStringLiteral("Restart count: %1").arg(restartCount), &window));
layout->addWidget(statusLabel);
window.show();
return app.exec();
}