QML Component Element

The progress of loading the component, from 0.0 (nothing loaded) to 1.0 (finished).

This property holds the status of component loading. It can be one of:

• Component.Null - no data is available for the component
• Component.Ready - the component has been loaded, and can be used to create instances.
• Component.Loading - the component is currently being loaded
• Component.Error - an error occurred while loading the component. Calling errorString() will provide a human-readable description of any errors.

The component URL. This is the URL that was used to construct the component.

Emitted after component "startup" has completed. This can be used to execute script code at startup, once the full QML environment has been established.

The Component::onCompleted attached property can be applied to any element. The order of running the onCompleted scripts is undefined.

 Rectangle {
     Component.onCompleted: console.log("Completed Running!")
     Rectangle {
         Component.onCompleted: console.log("Nested Completed Running!")
     }
 }

Emitted as the component begins destruction. This can be used to undo work done in the onCompleted signal, or other imperative code in your application.

The Component::onDestruction attached property can be applied to any element. However, it applies to the destruction of the component as a whole, and not the destruction of the specific object. The order of running the onDestruction scripts is undefined.

 Rectangle {
     Component.onDestruction: console.log("Destruction Beginning!")
     Rectangle {
         Component.onDestruction: console.log("Nested Destruction Beginning!")
     }
 }

See also QtDeclarative.

Creates and returns an object instance of this component that will have the given parent and properties. The properties argument is optional. Returns null if object creation fails.

The object will be created in the same context as the one in which the component was created. This function will always return null when called on components which were not created in QML.

If you wish to create an object without setting a parent, specify null for the parent value. Note that if the returned object is to be displayed, you must provide a valid parent value or set the returned object's parent property, or else the object will not be visible.

If a parent is not provided to createObject(), a reference to the returned object must be held so that it is not destroyed by the garbage collector. This is true regardless of whether Item::parent is set afterwards, since setting the Item parent does not change object ownership; only the graphical parent is changed.

As of QtQuick 1.1, this method accepts an optional properties argument that specifies a map of initial property values for the created object. These values are applied before object creation is finalized. (This is more efficient than setting property values after object creation, particularly where large sets of property values are defined, and also allows property bindings to be set up before the object is created.)

The properties argument is specified as a map of property-value items. For example, the code below creates an object with initial x and y values of 100 and 200, respectively:

 var component = Qt.createComponent("Button.qml");
 if (component.status == Component.Ready)
     component.createObject(parent, {"x": 100, "y": 100});

Dynamically created instances can be deleted with the destroy() method. See Dynamic Object Management in QML for more information.

Returns a human-readable description of any errors.

The string includes the file, location, and description of each error. If multiple errors are present they are separated by a newline character.

If no errors are present, an empty string is returned.