1 | /****************************************************************************
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2 | **
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3 | ** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
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4 | ** All rights reserved.
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5 | ** Contact: Nokia Corporation (qt-info@nokia.com)
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6 | **
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7 | ** This file is part of the documentation of the Qt Toolkit.
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8 | **
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9 | ** $QT_BEGIN_LICENSE:FDL$
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10 | ** Commercial Usage
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11 | ** Licensees holding valid Qt Commercial licenses may use this file in
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12 | ** accordance with the Qt Commercial License Agreement provided with the
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13 | ** Software or, alternatively, in accordance with the terms contained in a
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14 | ** written agreement between you and Nokia.
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15 | **
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16 | ** GNU Free Documentation License
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17 | ** Alternatively, this file may be used under the terms of the GNU Free
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18 | ** Documentation License version 1.3 as published by the Free Software
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19 | ** Foundation and appearing in the file included in the packaging of this
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20 | ** file.
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21 | **
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22 | ** If you have questions regarding the use of this file, please contact
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23 | ** Nokia at qt-info@nokia.com.
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24 | ** $QT_END_LICENSE$
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25 | **
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26 | ****************************************************************************/
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27 |
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28 | /*!
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29 | \page qdeclarativedebugging.html
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30 | \title Debugging QML
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31 |
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32 | \section1 Logging
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33 |
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34 | \c console.log can be used to print debugging information to the console. For example:
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35 |
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36 | \qml
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37 | Rectangle {
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38 | width: 200; height: 200
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39 | MouseArea {
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40 | anchors.fill: parent
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41 | onClicked: console.log("clicked")
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42 | }
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43 | }
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44 | \endqml
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45 |
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46 | \section1 Debugging Transitions
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47 |
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48 | When a transition doesn't look quite right, it can be helpful to view it in slow
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49 | motion to see what is happening more clearly. This functionality is supported
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50 | in the \l {QML Viewer} tool: to enable this,
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51 | click on the "Debugging" menu, then "Slow Down Animations".
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52 |
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53 |
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54 | \section1 Debugging module imports
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55 |
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56 | The \c QML_IMPORT_TRACE environment variable can be set to enable debug output
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57 | from QML's import loading mechanisms.
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58 |
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59 | For example, for a simple QML file like this:
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60 |
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61 | \qml
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62 | import QtQuick 1.0
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63 |
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64 | Rectangle { width: 100; height: 100 }
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65 | \endqml
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66 |
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67 | If you set \c {QML_IMPORT_TRACE=1} before running the \l {QML Viewer}
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68 | (or your QML C++ application), you will see output similar to this:
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69 |
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70 | \code
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71 | QDeclarativeImportDatabase::addImportPath "/qt-sdk/imports"
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72 | QDeclarativeImportDatabase::addImportPath "/qt-sdk/bin/QMLViewer.app/Contents/MacOS"
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73 | QDeclarativeImportDatabase::addToImport 0x106237370 "." -1.-1 File as ""
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74 | QDeclarativeImportDatabase::addToImport 0x106237370 "Qt" 4.7 Library as ""
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75 | QDeclarativeImportDatabase::resolveType "Rectangle" = "QDeclarativeRectangle"
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76 | \endcode
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77 |
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78 |
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79 | \section1 Debugging with Qt Creator
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80 |
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81 | \l{http://qt.nokia.com/products/developer-tools}{Qt Creator} provides built-in
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82 | support for QML debugging. QML projects and standalone C++ applications that
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83 | utilize QML can be debugged on desktops as well as on remote devices.
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84 | For more information, see the Qt Creator Manual.
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85 |
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86 | */
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