Explicit Animation (animateTo)

With animateTo, you can build explicit animations for state changes caused by closure code. In an explicit animation that involves width and height changes, as in a property animation, 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

The APIs of this module are supported since API version 7. Updates will be marked with a superscript to indicate their earliest API version.

The functionality of this module depends on UI context. This means that the APIs of this module cannot be used where the UI context is unclear. For details, see UIContext.

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

Since API version 10, you can use the animateTo API in UIContext to obtain the UI context.

APIs

animateTo(value: AnimateParam, event: () => void): void

Parameters

AnimateParam

ExpectedFrameRateRange¹¹⁺

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 AnimateToExample {
  @State widthSize: number = 250
  @State heightSize: number = 100
  @State rotateAngle: number = 0
  private flag: boolean = true

  build() {
    Column() {
      Button('change size')
        .width(this.widthSize)
        .height(this.heightSize)
        .margin(30)
        .onClick(() => {
          if (this.flag) {
            animateTo({
              duration: 2000,
              curve: Curve.EaseOut,
              iterations: 3,
              playMode: PlayMode.Normal,
              onFinish: () => {
                console.info('play end')
              }
            }, () => {
              this.widthSize = 150
              this.heightSize = 60
            })
          } else {
            animateTo({}, () => {
              this.widthSize = 250
              this.heightSize = 100
            })
          }
          this.flag = !this.flag
        })
      Button('change rotate angle')
        .margin(50)
        .rotate({ x: 0, y: 0, z: 1, angle: this.rotateAngle })
        .onClick(() => {
          animateTo({
            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,
            onFinish: () => {
              console.info('play end')
            },
            expectedFrameRateRange: {
              min: 10,
              max: 120,
              expected: 60,
            }
          }, () => {
            this.rotateAngle = 90
          })
        })
    }.width('100%').margin({ top: 5 })
  }
}