qml | 易学教程

Propagate QML events to C++

阅读更多关于 Propagate QML events to C++

问题 I would like to propagate event from a QML signal handler to C++ procedure but don't know how to pass the "event object". Take a look at this situation and pay particular attention to SomeType . First I create a custom QML item with a slot that can be called from QML: class Tool : public QQuickItem { . . . public slots: virtual void onMousePositionChanged(SomeType *event); } Then, in QML, I create a MouseArea and an instance of my custom object to which I wanto to propagate events to.

QML基础——基本语法

阅读更多关于 QML基础——基本语法

QML 的基本语法 QML看起来像这样 import Qt 4.7 Rectangle { width: 200 height: 200 color: "blue" Image { source: "pics/logo.png" anchors.centerIn: parent } } 对象是通过类型而直接被指定的，紧随其后的是一对大括号。对象类型总是以大写字母开头。在上面的例子中，存在两个对象Rectangle和Image。在大括号之间，我们可以指定对象的相关信息，例如它的属性。属性是通过“property: value”这样的方式被呈现的。在上面的例子中，我们可以看到Image拥有一个属性叫做source，它被分配了一个值叫做"pics/logo.png"。属性和值被冒号分隔。属性可以被一行行指定： Rectangle { width: 100 height: 100 } 或单行输写多个属性： Rectangle { width: 100; height: 100 } 当单行输写多属性 / 值时，必须由分号来分隔开来。 Import 语句导入 Qt 模块，它包含所有标准的 QML 元素。如果没有 Import 语句；那么 R ectangle 与 Image 元素将无效。表达式除了赋值属性外；你也可以用 JavaScript 编写的表达式来指定。 Rotation

How to get previous property value before it changed? (in QML)

阅读更多关于 How to get previous property value before it changed? (in QML)

问题 I want to understand the following question: How can I store the previous value of a property in the declarative QML language? The task is to memorize property value to another property before it change. The problem is that the existing signal mechanism onPropertyNameChanged() . This mechanism emits a signal about the property change after its modification. And in this handler it is impossible to get the previous value of the property for memorize it. It is desirable to see code examples. 回答1

QML file include - or one monolithic file (structure QML code)?

阅读更多关于 QML file include - or one monolithic file (structure QML code)?

问题 This is a QML newbie question. From the table view example I have code like this: Column { anchors.top: toolbar.bottom ..... TabView { id:frame ...... Tab { title: "XmlListModel" ... } Tab { ... As the qml file gets quite long, I wonder if I can have nested qml files Column { anchors.top: toolbar.bottom ..... TabView { id:frame ...... <include tab 1 qml file> <-- possible ????? ------- <include tab 2 qml file> If such an include is not possible, how does a QML programmer structure his code?

QML ListView draws ObjectModel outside of its bounds

阅读更多关于 QML ListView draws ObjectModel outside of its bounds

问题 I'm trying to get into QT/QML coming from WPF/XAML. In a test GUI, I'm using a ListView to display different Models on click of a button. This works alright so far, the view keeps showing each model when I click the corresponding button. But it still draws all the other models outside of its own bounds, overlapping surrounding elements with them. Can I turn this behaviour off? This is my ListView: ListView { id: list_view anchors.fill: parent model: main_view_model snapMode: ListView

QML ListView draws ObjectModel outside of its bounds

阅读更多关于 QML ListView draws ObjectModel outside of its bounds

How to quit the C++ application in Qt QML

阅读更多关于 How to quit the C++ application in Qt QML

问题 according to the Qt qml Type documentation quit() This function causes the QQmlEngine::quit() signal to be emitted. Within the Prototyping with qmlscene, this causes the launcher application to exit; to quit a C++ application when this method is called, connect the QQmlEngine::quit() signal to the QCoreApplication::quit() slot. so in order to quit the C++ application in QML i have to call this Qt.quit() inside the QML files, but that only quits the QML engine i need to close the C++

Flow layout with centered content

阅读更多关于 Flow layout with centered content

问题 I have a row with items which should stack when the window width gets too small for displaying all items in a row, as shown in the following sketch: The Flow component stacks the items but they are not centered but aligned on the left or right side: Flow { Item {} Item {} Item {} Item {} Item {} } Is there a built-in way in QML to make the flow centered? 回答1: Well there is no built-in way but I found a workaround to do it. The idea is simple, since Flow is already an Item it has anchors

Create QML object from C++ with specified properties

阅读更多关于 Create QML object from C++ with specified properties

问题 Dynamically instantiating a QML object from C++ is well documented, but what I can't find is how to instantiate it with pre-specified values for it's properties. For example, I am creating a slightly modified SplitView from C++ like this: QQmlEngine* engine = QtQml::qmlEngine( this ); QQmlComponent splitComp( engine, QUrl( "qrc:/qml/Sy_splitView.qml" ) ); QObject* splitter = splitComp.create(); splitter->setProperty( "orientation", QVariant::fromValue( orientation ) ); The problem I have is

How can i add property dynamically to a QML element?

阅读更多关于 How can i add property dynamically to a QML element?

问题 I want to add properties dynamically to a QML element: Item { id: dynamicProperty; property int first; Component.onCompleted: { /* once this block of code is executed, i want to add property int second; property bool third; property variant fourth; */ } } Is there any way to accomplish the above task. 回答1: I don't think QML was designed to support dynamic property creation. Depending on your use-case this could be worked around with "script instances" (I made up the term). Basically each QML