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/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing
**
** 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 {Qt Creator Manual}
\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{QML Advanced Tutorial}{Same Game}
example application to illustrate how to debug Qt Quick applications in the
\uicontrol 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
\li 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.
\li Select \uicontrol {Debug > Start Debugging > Start Debugging} or press
\key{F5}.
\li Once the Same Game application starts, click the \uicontrol {New Game}
button to start a new game.
\li 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
\li Click the
\inlineimage qtcreator-debug-button-step-into.png
(\uicontrol {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
\li Examine the local variables in the \uicontrol {Locals and Expressions}
view. Step through the code to see how the information changes in
the view.
\li Add a breakpoint at the end of the \c {startNewGame()} function, and
click \inlineimage qtcreator-debugging-continue.png
(\uicontrol Continue) to hit the breakpoint.
\image qtquick-example-setting-breakpoint3.png
\li To execute JavaScript commands in the current context, open the
\uicontrol {QML/JS Console} output pane.
\li To change the score to 1000, enter \c{gameCanvas.score = 1000}
in the console.
\image qtquick-example-script-console.png
\li To remove a breakpoint, right-click it and select
\uicontrol {Delete Breakpoint}.
\li Select the \uicontrol {Locals and Expressions} tab to explore the object
structure at runtime:
\image qtquick-example-qml-inspector.png
\li Click
\inlineimage qml-inspector-app-on-top.png
(\uicontrol {Show Application on Top}) to keep the application visible
while you interact with the debugger.
\li Click
\inlineimage qml-inspector-select-button.png
(\uicontrol Select) to activate selection mode and then click the
\uicontrol {Quit} button to move into the \uicontrol ButtonLabel component
in the \uicontrol {QML/JS Console} and the code editor.
\li In the \uicontrol {Locals and Expressions} view, double-click the value of
the \c text property to change it temporarily from \uicontrol {Quit} to
\uicontrol {End Game}.
\image qtquick-example-property-values.png
When you select an element, the cursor moves to it in the code
editor, where you can change the value permanently.
\endlist
*/
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