Specifying Custom Properties

Each preset component has a set of preset properties that you can specify values for. You can add custom properties that would not otherwise exist for a particular component type. You bind the properties to dynamic expressions to define global properties for a component that can be read by other components. For example, you can specify global properties for the root component that you can use in the child components.

For example, to specify spacing between UI elements, you could define a margin for a component that does not have a margin property, and then use bindings to refer to the value of the margin property from other components.

Similarly, you can add custom properties for your own components that are based on preset components.

Any content that is data-driven should be exported as a public property (alias property) of the relevant component. For example, a speedometer should have an int or real property for speed to which the UI is bound.

Adding Properties for a Component

To add a custom property for a component:

  1. Go to the Local Custom Properties section in the Properties view.
  2. Select the (Add) button to add a custom property for the currently selected component.

  3. Set the Name and Type for the property.

Binding a Property Value

To bind the value of the property to that of another one or to data accessible in the application.

  1. In the Properties view, select next to the property.
  2. Select Set Binding.

    "Binding Editor"

For more information, see Setting Bindings.

Adding a Custom Property to a Component from the Connections View

You can add a custom property to a component from the Connections view. Follow the process:

  1. Select the component you want to add a Custom property to in the 2D view or in the Navigator view.
  2. Select Properties from the Connections view.

  3. Select the (Add) button to add a Custom property.
  4. From the pop-up Custom property editor, select the Type of the property you want to include.

  5. Next, set the Name of the property.
  6. Set a value to the Custom property in the Value field.

Note: Select the (Remove) to delete a Custom Property.

Supported Property Types

The following table describes the supported property types:

aliasProperty alias that holds a reference to another property
boolBinary true or false value
colorColor value that can be specified by using an SVG color name, such as "red", "green", or "lightsteelblue", or a hexadecimal triplet or quad in the form "#RRGGBB" and "#AARRGGBB", respectively. For example, the color red corresponds to a triplet of "#FF0000" and a slightly transparent blue to a quad of "#800000FF". In addition, you can use the following Qt functions: Qt.rgba(), Qt.hsva(), Qt.hsla(), Qt.darker(), Qt.lighter(), and Qt.tint().
intWhole integer number, such as 0, 10, or -20
realNumber with a decimal point
stringFree form text string
TextureInputSpecifies a texture exposed to the shaders of a CustomMaterial or Effect.
urlResource locator, such as a file name. It can be either absolute, (http://qt-project.org), or relative (pics/logo.png). A relative URL is resolved relative to the URL of the parent component.
variantGeneric property type. For example, variant properties can store numbers, strings, objects, arrays, and functions.
vector2dRefers to a value with x and y attributes.
vector3dRefers to a value with x, y, and z attributes.
vector4dRefers to a value with x, y, z, and w attributes.

See also Specifying Component Properties.

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