diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/declarative/qmlevents.qdoc | 22 | ||||
| -rw-r--r-- | doc/src/snippets/declarative/events.qml | 141 |
2 files changed, 150 insertions, 13 deletions
diff --git a/doc/src/declarative/qmlevents.qdoc b/doc/src/declarative/qmlevents.qdoc index 277d811..7d5e962 100644 --- a/doc/src/declarative/qmlevents.qdoc +++ b/doc/src/declarative/qmlevents.qdoc @@ -54,9 +54,7 @@ signal <name>[([<type> <parameter name>[, ...]])] \endqml Attempting to declare two signals or methods with the same name in the same type -block is an error. However, a new signal may reuse the name of an existing -signal on the type. (This should be done with caution, as the existing signal -may be hidden and become inaccessible.) +block generates an error. However, a new signal may reuse the name of an existing signal on the type. (This should be done with caution, as the existing signal may be hidden and become inaccessible.) Here are various examples of signal declarations: \snippet doc/src/snippets/declarative/events.qml parent begin @@ -96,31 +94,29 @@ QML are created as \l{Signals & Slots}{Qt slots}.) This enables a signal to be received by a method instead of a \l {Signal Handlers}{signal handler}. \snippet doc/src/snippets/declarative/events.qml connect method -The \c {connect()} method is appropriate when connecting a JavaScript method, -such as the \c {callee}'s\c answer method, to QML signals. +The \c {connect()} method is appropriate when connecting a JavaScript method to +a signal. -The corresponding \c disconnect() method is for removing connected -signals. The following code removes the connection created in \c application.qml above: -\snippet doc/src/snippets/declarative/events.qml disconnect method +There is a corresponding \c disconnect() method for removing connected +signals. \section3 Signal to Signal Connect By connecting signals to other signals, the \c connect() method can form different signal chains. -\snippet doc/src/snippets/declarative/events.qml parent begin \snippet doc/src/snippets/declarative/events.qml forward signal -\snippet doc/src/snippets/declarative/events.qml parent end -Whenever the \l MouseArea \c clicked signal is emitted, the \c widgetClicked + +Whenever the \l MouseArea \c clicked signal is emitted, the \c send signal will automatically be emitted as well. \code output: MouseArea clicked - Widget clicked + Send clicked \endcode -\section1 C++ additions +\section1 C++ Additions Because QML uses Qt, a signal defined in C++ also works as a QML signal. The signal may be emitted in QML code or called as a method. In addition, the QML diff --git a/doc/src/snippets/declarative/events.qml b/doc/src/snippets/declarative/events.qml new file mode 100644 index 0000000..52fc2bc --- /dev/null +++ b/doc/src/snippets/declarative/events.qml @@ -0,0 +1,141 @@ +/**************************************************************************** +** +** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies). +** All rights reserved. +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:BSD$ +** You may use this file under the terms of the BSD license as follows: +** +** "Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions are +** met: +** * Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** * Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor +** the names of its contributors may be used to endorse or promote +** products derived from this software without specific prior written +** permission. +** +** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." +** $QT_END_LICENSE$ +** +****************************************************************************/ +//![document] +import QtQuick 1.0 + +//![parent begin] +Rectangle { +//![parent begin] + + id: screen + width: 400; height: 500 + +//! [signal declaration] + signal trigger + signal send (string notice) + signal perform (string task, variant object) +//! [signal declaration] + +//! [signal handler declaration] +onTrigger: console.log("trigger signal emitted") + +onSend: { + console.log("send signal emitted with notice: " + notice) +} + +onPerform: console.log("perform signal emitted") +//! [signal handler declaration] + +//! [automatic signals] +Rectangle { + id: sprite + width: 25; height: 25 + x: 50; y: 15 + + onXChanged: console.log("x property changed, emitted xChanged signal") + onYChanged: console.log("y property changed, emitted yChanged signal") +} +//! [automatic signals] + +//! [signal emit] +Rectangle { + id: messenger + + signal send( string person, string notice) + + onSend: { + console.log("For " + person + ", the notice is: " + notice) + } + + Component.onCompleted: messenger.send("Tom", "the door is ajar.") +} +//! [signal emit] + +//! [connect method] +Rectangle { + id: relay + + signal send( string person, string notice) + onSend: console.log("Send signal to: " + person + ", " + notice) + + Component.onCompleted: { + relay.send.connect(sendToPost) + relay.send.connect(sendToTelegraph) + relay.send.connect(sendToEmail) + relay.send("Tom", "Happy Birthday") + } + + function sendToPost(person, notice) { + console.log("Sending to post: " + person + ", " + notice) + } + function sendToTelegraph(person, notice) { + console.log("Sending to telegraph: " + person + ", " + notice) + } + function sendToEmail(person, notice) { + console.log("Sending to email: " + person + ", " + notice) + } +} +//! [connect method] + +//! [forward signal] +Rectangle { + id: forwarder + width: 100; height: 100 + + signal send() + onSend: console.log("Send clicked") + + MouseArea { + id: mousearea + anchors.fill: parent + onClicked: console.log("MouseArea clicked") + } + Component.onCompleted: { + mousearea.clicked.connect(send) + } +} +//! [forward signal] + +//! [connect method] +//![parent end] +} +//![parent end] + +//![document] |