/**************************************************************************** ** ** Copyright (c) 2012 Digia Plc and/or its subsidiary(-ies). ** Contact: http://www.qt-project.org/legal ** ** This file is part of Qt Creator ** ** ** GNU Free Documentation License ** ** Alternatively, this file may be used under the terms of the GNU Free ** Documentation License version 1.3 as published by the Free Software ** Foundation and appearing in the file included in the packaging of this ** file. ** ** ****************************************************************************/ // ********************************************************************** // NOTE: the sections are not ordered by their logical order to avoid // reshuffling the file each time the index order changes (i.e., often). // Run the fixnavi.pl script to adjust the links to the index order. // ********************************************************************** /*! \contentspage index.html \previouspage creator-debugging-example.html \page creator-qml-debugging-example.html \nextpage creator-troubleshooting-debugging.html \title Debugging a Qt Quick Example Application This section uses the \l{http://qt-project.org/doc/qt-4.8/demos-declarative-samegame.html}{Same Game} demo application to illustrate how to debug Qt Quick applications in the \gui Debug mode. For more information about all the options you have, see \l{Debugging Qt Quick Projects}. The Same Game demo shows how to write a game in QML, using JavaScript for all the game logic. Open the demo project in \QC to debug it: \list 1 \o To look at the code that starts a new game, place a breakpoint in samegame.qml by clicking between the line number and the window border on the line where where the \c startNewGame() function is called (1). \image qtquick-example-setting-breakpoint1.png The red circle indicates that a breakpoint is now set on that line number. \o Select \gui {Debug > Start Debugging > Start Debugging} or press \key{F5}. \o Once the Same Game application starts, click the \gui {New Game} button to start a new game. \o When the debugger hits the breakpoint, it interrupts the application. \QC displays the nested function calls leading to the current position as a call stack trace (1). \image qtquick-example-setting-breakpoint2.png \o Click the \inlineimage qtcreator-debug-button-step-into.png (\gui {Step Into}) button on the toolbar or press \key F11 to step into the code in the stack. The samegame.js file opens in the code editor at the function that starts a new game. \image qtquick-example-stack.png \o Examine the local variables in the \gui {Locals and Expressions} view. Step through the code to see how the information changes in the view. \o Add a breakpoint at the end of the \c {startNewGame()} function, and click \inlineimage qtcreator-debugging-continue.png (\gui Continue) to hit the breakpoint. \image qtquick-example-setting-breakpoint3.png \o To execute JavaScript commands in the current context, select the \gui {Console} tab. \o To change the score to 1000, enter \c{gameCanvas.score = 1000} in the console. \image qtquick-example-script-console.png \o To remove a breakpoint, right-click it and select \gui {Delete Breakpoint}. \o Select the \gui {Locals and Expressions} tab to explore the object structure at runtime: \image qtquick-example-qml-inspector.png \o Click \inlineimage qml-inspector-app-on-top.png (\gui {Show Application on Top}) to keep the application visible while you interact with the debugger. \o Click \inlineimage qml-inspector-select-button.png (\gui Select) to activate selection mode and then click the \gui {Quit} button to move into the \gui ButtonLabel component in the \gui {Console} and the code editor. \image qtquick-example-property-values.png \o In the \gui {Locals and Expressions} view, double-click the value of the \c text property to change it temporarily from \gui {Quit} to \gui {End Game}. When you select an element, the cursor moves to it in the code editor, where you can change the value permanently. \endlist */