Qt Reference Documentation

QML Animation Element

The Animation element is the base of all QML animations. More...

Inherited by AnchorAnimation, ParallelAnimation, ParentAnimation, PauseAnimation, PropertyAction, PropertyAnimation, ScriptAction, SequentialAnimation, and SpringAnimation.

  • List of all members, including inherited members
  • Properties

    Methods

    Detailed Description

    The Animation element cannot be used directly in a QML file. It exists to provide a set of common properties and methods, available across all the other animation types that inherit from it. Attempting to use the Animation element directly will result in an error.

    Property Documentation

    alwaysRunToEnd : bool

    This property holds whether the animation should run to completion when it is stopped.

    If this true the animation will complete its current iteration when it is stopped - either by setting the running property to false, or by calling the stop() method. The complete() method is not effected by this value.

    This behavior is most useful when the repeat property is set, as the animation will finish playing normally but not restart.

    By default, the alwaysRunToEnd property is not set.


    loops : int

    This property holds the number of times the animation should play.

    By default, loops is 1: the animation will play through once and then stop.

    If set to Animation.Infinite, the animation will continuously repeat until it is explicitly stopped - either by setting the running property to false, or by calling the stop() method.

    In the following example, the rectangle will spin indefinately.

     Rectangle {
         width: 100; height: 100; color: "green"
         RotationAnimation on rotation {
             loops: Animation.Infinite
             from: 0
             to: 360
         }
     }

    paused : bool

    This property holds whether the animation is currently paused.

    The paused property can be set to declaratively control whether or not an animation is paused.

    Animations can also be paused and resumed imperatively from JavaScript using the pause() and resume() methods.

    By default, animations are not paused.


    running : bool

    This property holds whether the animation is currently running.

    The running property can be set to declaratively control whether or not an animation is running. The following example will animate a rectangle whenever the MouseArea is pressed.

     Rectangle {
         width: 100; height: 100
         NumberAnimation on x {
             running: myMouse.pressed
             from: 0; to: 100
         }
         MouseArea { id: myMouse }
     }

    Likewise, the running property can be read to determine if the animation is running. In the following example the text element will indicate whether or not the animation is running.

     NumberAnimation { id: myAnimation }
     Text { text: myAnimation.running ? "Animation is running" : "Animation is not running" }

    Animations can also be started and stopped imperatively from JavaScript using the start() and stop() methods.

    By default, animations are not running. Though, when the animations are assigned to properties, as property value sources using the on syntax, they are set to running by default.


    Method Documentation

    Animation::complete ()

    Stops the animation, jumping to the final property values.

    If the animation is not running, calling this method has no effect. The running property will be false following a call to complete().

    Unlike stop(), complete() immediately fast-forwards the animation to its end. In the following example,

     Rectangle {
         NumberAnimation on x { from: 0; to: 100; duration: 500 }
     }

    calling stop() at time 250ms will result in the x property having a value of 50, while calling complete() will set the x property to 100, exactly as though the animation had played the whole way through.


    Animation::pause ()

    Pauses the animation.

    If the animation is already paused, calling this method has no effect. The paused property will be true following a call to pause().


    Animation::restart ()

    Restarts the animation.

    This is a convenience method, and is equivalent to calling stop() and then start().


    Animation::resume ()

    Resumes a paused animation.

    If the animation is not paused, calling this method has no effect. The paused property will be false following a call to resume().


    Animation::start ()

    Starts the animation.

    If the animation is already running, calling this method has no effect. The running property will be true following a call to start().


    Animation::stop ()

    Stops the animation.

    If the animation is not running, calling this method has no effect. The running property will be false following a call to stop().

    Normally stop() stops the animation immediately, and the animation has no further influence on property values. In this example animation

     Rectangle {
         NumberAnimation on x { from: 0; to: 100; duration: 500 }
     }

    was stopped at time 250ms, the x property will have a value of 50.

    However, if the alwaysRunToEnd property is set, the animation will continue running until it completes and then stop. The running property will still become false immediately.


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