harmony 鸿蒙Property Animation

2022-08-09
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Property Animation

With property animations, you can animate changes to certain component properties, such as width, height, backgroundColor, opacity, scale, rotate, and translate. In a property animation that involves width and height changes, a component’s content (such as text, canvas content, and linear gradient) is changed straight to the final state. To enable the content to change with the width and height during the animation process, you can use the renderFit attribute.

NOTE

This event is supported since API version 7. Updates will be marked with a superscript to indicate their earliest API version.

animation(value: {duration?: number, tempo?: number, curve?: string|Curve|ICurve, delay?:number, iterations?: number, playMode?: PlayMode, onFinish?: () => void})

Since API version 9, this API is supported in ArkTS widgets.

Parameters

Name	Type	Mandatory	Description
duration	number	No	Animation duration, in ms. Default value: 1000 Since API version 9, this API is supported in ArkTS widgets. NOTE - The maximum animation duration on an ArkTS widget is 1000 ms. - A value less than 0 evaluates to the value 0. - Floating-point values will be rounded down to integers. For example, if the value set is 1.2, 1 will be used.
tempo	number	No	Animation playback speed. A larger value indicates a higher animation playback speed. The value 0 indicates that no animation is applied. Default value: 1 NOTE A value less than 0 evaluates to the value 1.
curve	string \|Curve \|ICurve⁹⁺	No	Animation curve. Default value: Curve.EaseInOut Since API version 9, this API is supported in ArkTS widgets.
delay	number	No	Delay of animation playback. The value 0 indicates that the playback is not delayed. Default value: 0 Value range: (-∞, +∞) NOTE - A value greater than 0 means to begin the animation after the specified amount of time has elapsed. A value less than 0 means to begin the animation in advance. If the absolute value of delay is less than the actual animation duration, the animation starts its first frame from the state at the absolute value. If the absolute value of delay is greater than or equal to the actual animation duration, the animation starts its first frame from the end state. The actual animation duration is equal to the duration of a single animation multiplied by the number of animation playback times. - Floating-point values will be rounded down to integers. For example, if the value set is 1.2, 1 will be used.
iterations	number	No	Number of times that the animation is played. Default value: 1 Value range: [-1, +∞) NOTE The value -1 indicates that the animation is played for an unlimited number of times. The value 0 indicates that no animation is applied.
playMode	PlayMode	No	Animation playback mode. By default, the animation is played from the beginning after the playback is complete. Default value: PlayMode.Normal Since API version 9, this API is supported in ArkTS widgets. For details about the restrictions, see Notes about PlayMode.
onFinish	() => void	No	Callback invoked when the animation playback is complete. Since API version 9, this API is supported in ArkTS widgets. NOTE This callback is not invoked when iterations is set to -1.

Notes about PlayMode: - PlayMode.Normal and PlayMode.Alternate are recommended. Under these settings, the first round of the animation is played forwards. If PlayMode.Reverse or PlayMode.AlternateReverse is used, the first round of the animation is played backwards. In this case, the animation jumps to the end state and then starts from there. - When using PlayMode.Alternate or PlayMode.AlternateReverse, make sure the final state of the animation is the same as the value of the state variable. In other words, make sure the last round of the animation is played forwards. When PlayMode.Alternate is used, iterations must be set to an odd number. When PlayMode.AlternateReverse is used, iterations must be set to an even number. - PlayMode.Reverse is not recommended. Under this setting, the animation jumps to the end state at the beginning, and its final state will be different from the value of the state variable.

Example

// xxx.ets
@Entry
@Component
struct AttrAnimationExample {
  @State widthSize: number = 250
  @State heightSize: number = 100
  @State rotateAngle: number = 0
  @State flag: boolean = true

  build() {
    Column() {
      Button('change size')
        .onClick(() => {
          if (this.flag) {
            this.widthSize = 150
            this.heightSize = 60
          } else {
            this.widthSize = 250
            this.heightSize = 100
          }
          this.flag = !this.flag
        })
        .margin(30)
        .width(this.widthSize)
        .height(this.heightSize)
        .animation({
          duration: 2000,
          curve: Curve.EaseOut,
          iterations: 3,
          playMode: PlayMode.Normal
        })
      Button('change rotate angle')
        .onClick(() => {
          this.rotateAngle = 90
        })
        .margin(50)
        .rotate({ angle: this.rotateAngle })
        .animation({
          duration: 1200,
          curve: Curve.Friction,
          delay: 500,
          iterations: -1, // The value -1 indicates that the animation is played for an unlimited number of times.
          playMode: PlayMode.Alternate
        })
    }.width('100%').margin({ top: 20 })
  }
}

animation