Transition QML Type

These properties indicate the state changes that trigger the transition.

The default values for these properties is "*" (that is, any state).

For example, the following transition has not set the to and from properties, so the animation is always applied when changing between the two states (i.e. when the mouse is pressed and released).

 Rectangle {
     id: rect
     width: 100; height: 100
     color: "red"

     MouseArea { id: mouseArea; anchors.fill: parent }

     states: State {
         name: "brighter"; when: mouseArea.pressed
         PropertyChanges { target: rect; color: "yellow" }
     }

     transitions: Transition {
         ColorAnimation { duration: 1000 }
     }
 }

If the transition was changed to this:

 transitions: Transition {
     to: "brighter"
     ColorAnimation { duration: 1000 }
 }

The animation would only be applied when changing from the default state to the "brighter" state (i.e. when the mouse is pressed, but not on release).

Multiple to and from values can be set by using a comma-separated string.

See also reversible.

This property holds a list of the animations to be run for this transition.

 transitions: Transition {
     PropertyAnimation { duration: 3000 }
     ColorAnimation { duration: 3000 }
 }

The top-level animations are run in parallel. To run them sequentially, define them within a SequentialAnimation:

 transitions: Transition {
     to: "brighter"
     reversible: true
     SequentialAnimation {
         PropertyAnimation { property: "x"; duration: 1000 }
         ColorAnimation { duration: 1000 }
     }
 }

This property holds whether the Transition will be run when moving from the from state to the to state.

By default a Transition is enabled.

Note that in some circumstances disabling a Transition may cause an alternative Transition to be used in its place. In the following example, although the first Transition has been set to animate changes from "state1" to "state2", this transition has been disabled by setting enabled to false, so any such state change will actually be animated by the second Transition instead.

 Item {
     states: [
         State { name: "state1" },
         State { name: "state2" }
     ]
     transitions: [
         Transition { from: "state1"; to: "state2"; enabled: false },
         Transition {
             // ...
         }
     ]
 }

This property holds whether the transition should be automatically reversed when the conditions that triggered this transition are reversed.

The default value is false.

By default, transitions run in parallel and are applied to all state changes if the from and to states have not been set. In this situation, the transition is automatically applied when a state change is reversed, and it is not necessary to set this property to reverse the transition.

However, if a SequentialAnimation is used, or if the from or to properties have been set, this property will need to be set to reverse a transition when a state change is reverted. For example, the following transition applies a sequential animation when the mouse is pressed, and reverses the sequence of the animation when the mouse is released:

 Rectangle {
     id: rect
     width: 100; height: 100
     color: "steelblue"

     TapHandler { id: tapHandler }

     states: State {
         name: "brighter"
         when: tapHandler.pressed
         PropertyChanges { target: rect; color: "lightsteelblue"; x: 50 }
     }

     transitions: Transition {
         to: "brighter"
         reversible: true
         SequentialAnimation {
             PropertyAnimation { property: "x"; duration: 1000 }
             ColorAnimation { duration: 1000 }
         }
     }
 }

If the transition did not set the to and reversible values, then on the mouse release, the transition would play the PropertyAnimation before the ColorAnimation instead of reversing the sequence.

This property holds whether the transition is currently running.

This property is read only.