Qt Script Tetrix Example
Overview
The program logic in this example is a fairly straight port of the logic in the C++ Tetrix Example. You may find it useful to compare the implementations of the TetrixBoard
, TetrixPiece
and TetrixWindow
classes to see how Qt Script is used to implement methods, call Qt functions, and emit signals.
Setting up the GUI
The graphical user interface is defined in a UI file, created using Qt Designer, and is set up in the example's C++ main.cpp
file.
class TetrixUiLoader : public QUiLoader { public: TetrixUiLoader(QObject *parent = 0) : QUiLoader(parent) { } virtual QWidget *createWidget(const QString &className, QWidget *parent = 0, const QString &name = QString()) { if (className == QLatin1String("TetrixBoard")) { QWidget *board = new TetrixBoard(parent); board->setObjectName(name); return board; } return QUiLoader::createWidget(className, parent, name); } };
We define a custom UI loader that handles our TetrixBoard
widget; this is the main component of the UI (where the pieces are drawn).
QApplication app(argc, argv); QScriptEngine engine; QScriptValue Qt = engine.newQMetaObject(QtMetaObject::get()); Qt.setProperty("App", engine.newQObject(&app)); engine.globalObject().setProperty("Qt", Qt);
We initialize the script engine to have the Qt namespace, so that e.g., Qt.Key_Left will be available to script code. We also make the application object available (for the quit() slot).
evaluateFile(engine, ":/tetrixpiece.js"); evaluateFile(engine, ":/tetrixboard.js"); evaluateFile(engine, ":/tetrixwindow.js");
Several scripts are evaluated as part of the engine setup process. The tetrixpiece.js
file contains the definition of the TetrixPiece
class, which is used to populate the play field. The tetrixboard.js
file contains the definition of the TetrixBoard
class, which contains the main game logic. Finally, tetrixwindow.js
contains the definition of the TetrixWindow
class, which wires up the top-level widget.
TetrixUiLoader loader; QFile uiFile(":/tetrixwindow.ui"); uiFile.open(QIODevice::ReadOnly); QWidget *ui = loader.load(&uiFile); uiFile.close(); QScriptValue ctor = engine.evaluate("TetrixWindow"); QScriptValue scriptUi = engine.newQObject(ui, QScriptEngine::ScriptOwnership); QScriptValue tetrix = ctor.construct(QScriptValueList() << scriptUi);
A form is created from the UI file. A new TetrixWindow
script object is then constructed, passing the form as its argument.
ui->resize(550, 370); ui->show(); qsrand(QTime(0,0,0).secsTo(QTime::currentTime())); return app.exec();
The form is shown, and the event loop is entered.
Files:
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