How to Create and Run Qt Application for Android

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How to Create and Run Qt Application for Android

Using "Necessitas":http://developer.qt.nokia.com/wiki/Necessitas Qt SDK developers can deploy Qt application on Android devices. The following tutorial will show the basics steps to create a simple Qt application for Android.

Requirements

• Installed Necessitas SDK
• Android device

Tutorial

1. Start Qt Creator from Necessitas Qt SDK
2. Press File > New file or project… and follow the instructions of the wizard
3. Select Qt Widget Project and Qt Gui Application
4. Enter project name and path to its directory
5. Select Android as a Target
6. When the project is created open the Projects view and verify the configurations for Build and Run settings
7. Modify the source code and when ready run the application on the device

Hints

• To modify general information about the application, Android Manifest file, Android Permissions or the list of libraries from Qt Creator go to Projects > Run Settings > Package configuration > Details.

• To select Android target SDK that you want to use from Qt Creator go to Projects > Run Settings > Package configuration > Details > Manifest.

• To modify deploy configuration of the project from Qt Creator go to Projects > Run Settings > Configuration configuration > Details.

Source Code

As you can see the source code does not include any specific Android features which makes absolutely portable. Some additional files required by necessitas are added at pro file of the project.

• test.pro

QT ''= core gui

TARGET = test
TEMPLATE = app


SOURCES''= main.cpp mainwindow.cpp

HEADERS ''= mainwindow.h

FORMS''= mainwindow.ui

CONFIG ''= mobility
MOBILITY =

OTHER_FILES''=  android/AndroidManifest.xml  android/res/drawable-hdpi/icon.png  android/res/drawable-ldpi/icon.png  android/res/drawable-mdpi/icon.png  android/res/values/libs.xml  android/res/values/strings.xml  android/src/eu/licentia/necessitas/industrius/QtActivity.java  android/src/eu/licentia/necessitas/industrius/QtApplication.java  android/src/eu/licentia/necessitas/industrius/QtLayout.java  android/src/eu/licentia/necessitas/industrius/QtSurface.java  android/src/eu/licentia/necessitas/ministro/IMinistro.aidl  android/src/eu/licentia/necessitas/ministro/IMinistroCallback.aidl  android/src/eu/licentia/necessitas/mobile/QtAndroidContacts.java  android/src/eu/licentia/necessitas/mobile/QtCamera.java  android/src/eu/licentia/necessitas/mobile/QtFeedback.java  android/src/eu/licentia/necessitas/mobile/QtLocation.java  android/src/eu/licentia/necessitas/mobile/QtMediaPlayer.java  android/src/eu/licentia/necessitas/mobile/QtSensors.java  android/src/eu/licentia/necessitas/mobile/QtSystemInfo.java

• main.cpp

#include <QtGui/QApplication>
#include "mainwindow.h"

int main(int argc, char '''argv[])
{
 QApplication a(argc, argv);
 MainWindow w;
#if defined(Q_WS_S60)
 w.showMaximized();
#else
 w.show();
#endif

 return a.exec();
}

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QLabel>

namespace Ui {
 class MainWindow;
}

class MainWindow : public QMainWindow
{
 Q_OBJECT

public:
 explicit MainWindow(QWidget '''parent = 0);
 ~MainWindow();

private:

 // from QMainWindow
 void resizeEvent(QResizeEvent''' event);

private:

QLabel* m_pLabel;
};

#endif // MAINWINDOW_H

• mainwindow.cpp

#include "mainwindow.h"

#include <QApplication>
#include <QDesktopWidget>
#include <QtCore/QCoreApplication>

MainWindow::MainWindow(QWidget '''parent) :
 QMainWindow(parent),
 m_pLabel(NULL)
{
 m_pLabel = new QLabel("Hello Qt for Android!", this);
 m_pLabel->setGeometry(QApplication::desktop()->screenGeometry());
 m_pLabel->setAlignment(Qt::AlignCenter);
 m_pLabel->setStyleSheet("background-color:#006600; color:#FFFFFF");
}

MainWindow::~MainWindow()
{

}

void MainWindow::resizeEvent(QResizeEvent''' /*event*/)
{
 m_pLabel->setGeometry(QApplication::desktop()->screenGeometry());
}

Testing

Connect your device to the computer and run the application from Necessitas Qt SDK Qt Creator. The Qt application will automatically start on the Android device. You might be prompted to download dependencies using Ministro. Follow the instruction to install all required components.

This example application has been successfully tested on "LG GT540 Optimus":http://www.gsmarena.com/lg_gt540_optimus-3081.php with Android 2.1.

See Also

"How to use Necessitas 0.2.1 Emulator on Windows 7":http://developer.qt.nokia.com/wiki/How_to_use_Necessitas_Emulator_on_Windows_7 "How to write Qt apps for Android":http://sourceforge.net/p/necessitas/wiki/How to write Qt apps for Android/ "Setup QtCreator":http://sourceforge.net/p/necessitas/wiki/Setup QtCreator/