Qt Quick UI Forms

You can use Qt Design Studio wizards to create UI forms that have the filename extension .ui.qml. The UI forms contain a purely declarative subset of the QML language. It is recommended that you edit the forms in the Design mode. Qt Design Studio enforces the use of the supported QML features by displaying error messages.

The following features are not supported:

  • JavaScript blocks
  • Other bindings than pure expressions
  • Signal handlers
  • States in other items than the root item
  • Root items that are not derived from QQuickItem or Item

The following types are not supported:

  • Behavior
  • Binding
  • Canvas
  • Component
  • Shader Effect
  • Timer
  • Transform
  • Transition

Supported Methods

Qt Design Studio supports most JavaScript functions that are supported by the QML engine, as well as a subset of Qt QML methods.

This section lists the functions that you can use in .ui.qml files.

JavaScript Functions

As a rule of thumb, pure functions are supported. They only depend on and modify states of parameters that are within their scope, and therefore always return the same results when given the same parameters. This makes it possible to convert and reformat property bindings without breaking the .ui.qml files.

The following JavaScript functions are supported:

  • charAt()
  • charCodeAt()
  • concat()
  • endsWith()
  • includes()
  • indexOf()
  • isFinite()
  • isNaN()
  • lastIndexOf()
  • substring()
  • toExponential()
  • toFixed()
  • toLocaleLowerCase()
  • toLocaleString
  • toLocaleUpperCase()
  • toLowerCase()
  • toPrecision()
  • toString()
  • toUpperCase()
  • valueOf()

In addition, all functions of the Math and Date objects are supported.

For more information, see List of JavaScript Objects and Functions.

Qt QML Methods

Qt Design Studio supports color methods, helper methods for creating objects of specific data types, and translation methods.

The following color methods are supported:

The following helper methods are supported:

The following translation methods are supported:

For more information about using the methods, see Qt QML Methods.

Using Qt Quick UI Forms

You can edit the forms in the Form Editor and Text Editor tabs in the Design mode. Items that are supposed to be used in QML code have to be exported as properties:

Item {
    width: 640
    height: 480

    property alias button: button

    Button {
        anchors.centerIn: parent
        id: button
        text: qsTr("Press Me")
    }
}

The property alias exports the button to the QML code that uses the form. You can use the (Export) button in the Navigator to export an item as a property:

In the QML file that uses the form, you can use the button property alias to implement signal handlers, for example. In the following code snippet, the UI form is called MainForm.ui.qml:

MainForm {
    anchors.fill: parent
    button.onClicked: messageDialog.show(qsTr("Button pressed"))
}

You can also assign properties or define behavior or transitions.

To move from the Design mode directly to the implementation of a type in the .qml file, right-click the type in the Navigator and select Go to Implementation in the context menu.

Available under certain Qt licenses.
Find out more.