Qt4 Hildon Legacy
Contents |
Intro
What is Maemo?
Few words about the Maemo software platform
What is Hildon?
Hildon is an application framework for Linux operating system mobile devices (PDAs, mobile phones, etc), developed by Nokia for Maemo and now a part of GNOME, that focuses on providing a finger friendly interface
Developing in Maemo
Maemo SDK
If you want to get more info about the Maemo SDK or simply you want to install it on your linux box this is the page that you want to check: SDK Releases
What is Scratchbox?
Scratchbox is a cross compilation toolkit designed to make embedded Linux application development easier. It also provides a full set of tools to integrate and cross compile an entire Linux distribution.
Installing the Maemo SDK (Scratchbox)
If you want to install the maemo SDK on your linux box this is the page that you want to check: SDK Releases
Porting a Qt application in Maemo
Intro
Basically porting a Qt application in Maemo means building your application for ARMEL. The Maemo Qt libraries will take care to give the Hildon Maemo look & Feel and to enable the hildon input method for your application.
How to compile a Qt application in scratchbox
All the Qt tools that you need are available in scratchbox. So in order to compile a Qt application you need to follow the standard Qt way:
qmake -project qmake file.pro make
Overriding the Qt maemo changes
Maemo Style
The Maemo style is the default style of the Qt applications that run in Maemo. The other styles available in Qt 4.4 maemo are QCleanLooks, Windows and Plastique (It will be available in the next packages of Qt).
You can force your application to use another style in several way:
1. Running your application with the flag -style <style_name>
$> ./qt-test-application -style windows
HINT: You can put this flag in the Exec field of the desktop file that launch the application.
2. If you want to change your code, you can use this static function:QApplication::setStyle( QStyle * style )
3. If you want to change the style only for a particular widget, you can call this function in the widget constructor: QWidget::setStyle( QStyle * style )
Showing the status bar
The hildon applications don't have a stuatus bar. Qt for maemo hide the status bar by default. You can show it again modifying your code. TODO
Limitations
TODO
Debugging a Qt application
GDB
Intro
The Gnu Project Debugger, or gdb for short, is a general purpose debugger that can be used for various debugging purposes.
Debugging a Qt application into scratchbox
TODO
Debugging a Qt application into the device
1. Installing gdb into the device
A. add the sdk tools repository to the catalogue list B. install gdb by using apt-get (require around 6 Mb of space)
2. Install the debug symbols files in scratchbox (ARMEL target)
apt-get install libqt4-dbg
3. Run the application (device side)
$gdbserver 0.0.0.0:1234 ./qtApplication
4. Run the gdb client on your host PC (scratchbox side)
[sbox-DIABLO_ARMEL: ~/TEST/svn/qt4-x11-4.4.0/examples/widgets/tablet] > gdb ./qtApplication
5. Set the target of gdb
(gdb) target remote 172.21.37.117:1234
6. Tell to gdb to continue to debug the application on the device
(gdb) continue
7. Wait some moments...
8. Your application will appear on the device screen.
9. Happy debugging!
Links
Packaging a Qt application for Maemo
Extended API
There is no API breaks in Maemo Qt. You can collect the info that you need to develop in Maemo with Qt checking the Official Qt 4.4 API Documentation and the list below. NOTE: This list is not yet complete and some changes will happen.
Double click radius The application can set the double click radius by using: static void QApplication::setDoubleClickRadius(int); static int QApplication::doubleClickRadius(); The default value is 20px, usually you don't need to change it.
QTableEvents are able to get the pressure value from the touchscreen. - The eventdeviceType is for the touchscreen is set to QTabletEvent::Stylus. Finger poke is emulated in scratchbox by the Middle Mouse button (NOTE: There is no Fullscreen VKB in scratchbox)
QInputEvents don't move the cursor. It's mandatory to get working the HIM moving the cursor via QInputMethodEvents. Why is it mandatory? Because if the user select text with the finger from the right to the left, we are able to remove the highlighted text, but the cursor will be moved on the last char instead to stay on the first one. To do that some changes has been added to some widget function like: widget::inputMethodEvent(QInputMethodEvent *e). Modifing that function in some custom widgets may be necessary. Don't reimplementing that function will break some fullscreen virtual keyboard features.
Hardcoded Keys: In the QMainWindow: - F6 - Toggle fullscreen the application - F4 - Shows/Hides the application context menu - Zoom in - is a standard key sequence QKeySequence::ZoomIn - Zoom out - is a standard key sequence QKeySequence::ZoomOut
Input Method: Every Qt widget that is able to receive text in Maemo Qt make use of the Hidon input context instead to use XIM. You don't need to add code to enable it. By the way every widget can set the mode allows the input method to focus on the type of input that the application is expecting. Qt widgets like QTextEdit, QLineEdit... set the right input method mode automatically. You need to set it only for some custom widgets. To set the HIC Mode you need to call: void QHildonInputContext::setInputMode(int mode); HIC Modes: HILDON_GTK_INPUT_MODE_ALPHA alphabetical characters and whitespace HILDON_GTK_INPUT_MODE_NUMERIC numbers 0-9 and the '-' character HILDON_GTK_INPUT_MODE_SPECIAL special characters HILDON_GTK_INPUT_MODE_HEXA hexadecimal characters; numbers 0-9, characters a-f, and A-F HILDON_GTK_INPUT_MODE_TELE telephone numbers; numbers 0-9, whitespace, and the characters "pwPW/().-+*#?," HILDON_GTK_INPUT_MODE_FULL unrestricted entry mode, combination of the alpha, numeric and special modes. HILDON_GTK_INPUT_MODE_MULTILINE the client contains multiple lines of text or accepts linebreaks in the input. HILDON_GTK_INPUT_MODE_INVISIBLE do not echo or save the input in the IM when entering sensitive information such as passwords. HILDON_GTK_INPUT_MODE_AUTOCAP automatically capitalize the first letter at the start of a sentence. HILDON_GTK_INPUT_MODE_DICTIONARY enable predictive dictionaries and learning based on the input. Example: [TODO]