QML Transition Element

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

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

 transitions: Transition {
     SequentialAnimation {
         PropertyAnimation { property: "x"; duration: 1000 }
         ColorAnimation { duration: 1000 }
     }
 }

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).

See also reversible.

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: "red"

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

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

     transitions: Transition {
         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.