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KotlinPleaseAnimate

Kotlin, please, can you animate my views ?

From florent37·Updated March 18, 2026·View on GitHub·
·Archived

A Kotlin way to declare and run beautiful animations ! Please be gentle with Kotlin :) The project is written primarily in Kotlin, distributed under the Apache License 2.0 license, first published in 2018. Key topics include: animate, animation, animator, design, duration.

Kotlin Please Animate

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Kotlin, please, can you animate my views ?

A Kotlin way to declare and run beautiful animations !
Please be gentle with Kotlin :)

<a href="https://goo.gl/WXW8Dc"> <img alt="Android app on Google Play" src="https://developer.android.com/images/brand/en_app_rgb_wo_45.png" /> </a>

gif

kotlin
please { animate(avatar) toBe { bottomOfItsParent(marginDp = 36f) leftOfItsParent(marginDp = 16f) width(40, keepRatio = true, toDp = true) } }.start()

Download

<a href='https://ko-fi.com/A160LCC' target='_blank'><img height='36' style='border:0px;height:36px;' src='https://az743702.vo.msecnd.net/cdn/kofi1.png?v=0' border='0' alt='Buy Me a Coffee at ko-fi.com' /></a>

In your module Download

groovy
implementation 'com.github.florent37:kotlinpleaseanimate:1.0.2'

This code describe the video above

kotlin
please(duration = 1500L) { animate(avatar) toBe { bottomOfItsParent(marginDp = 36f) leftOfItsParent(marginDp = 16f) visible() width(40, keepRatio = true, toDp = true) } animate(name) toBe { rightOf(avatar, marginDp = 16f) sameCenterVerticalAs(avatar) textColor(Color.WHITE) } animate(subname) toBe { rightOf(name, marginDp = 5f) sameCenterVerticalAs(name) textColor(Color.WHITE) } animate(revert) toBe { rightOfItsParent(marginDp = 4f) bottomOfItsParent(marginDp = 12f) backgroundAlpha(0f) } animate(start) toBe { aboveOf(revert, marginDp = 4f) rightOfItsParent(marginDp = 4f) backgroundAlpha(0f) } animate(bottomLayout) toBe { originalPosition() } animate(content) toBe { originalPosition() visible() } }.start()

Follow scroll

gif

Use setPercent to apply modify the current step of the animation

Exemple with a scrollview

kotlin
val animation = please { animate(avatar) toBe { topOfItsParent(marginDp = 20f) leftOfItsParent(marginDp = 20f) scale(0.5f, 0.5f) } animate(username) toBe { rightOf(avatar, marginDp = 16f) sameCenterVerticalAs(avatar) alpha(0.5f) } animate(revert) toBe { rightOfItsParent(marginDp = 20f) sameCenterVerticalAs(avatar) } animate(background) toBe { height(h, horizontalGravity = Gravity.LEFT, verticalGravity = Gravity.TOP) } } scrollview.setOnScrollChangeListener(NestedScrollView.OnScrollChangeListener { v, scrollX, scrollY, oldScrollX, oldScrollY -> val percent = scrollY * 1f / v.maxScrollAmount animation.setPercent(percent) })

Chain animations

Just ask the kotlin's animation if he wants to execute another animation after, using thenCouldYou animate

please(duration = 1000L) {
   animate(image, withCameraDistance = 500f) toBe {
      flippedHorizontally()
   }
}.thenCouldYou(duration = 500L) {
   animate(image, withCameraDistance = 1000f) toBe {
      alpha(0.5f)
   }
}.start()

Apply directly

If you want your animation to be applied directly, be bossy with kotlin and force it to apply it using now() !

kotlin
please { animate(view) toBe { outOfScreen(Gravity.BOTTOM) } }.now();

Reset

Use reset to return to the initial state of views

kotlin
animation.reset():

List of expectations

please {
  animate(view) { //toBe is optional

     rightOf(view, marginDp=)
     leftOf(view, marginDp=)
     belowOf(view, marginDp=)
     aboveOf(view, marginDp=)

     originalPosition()

     sameCenterAs(view, horizontal=, vertical=)
     sameCenterHorizontalAs(view)
     sameCenterVerticalAs(view)
     centerInParent(horizontal=, vertical=)
     centerVerticalInParent()
     centerHorizontalInParent()

     centerBetweenViews(view1, view2, horizontal, vertical)
     centerBetweenViewAndParent(otherView, horizontal, vertical, toBeOnRight, toBeOnBottom)

     topOfItsParent()
     rightOfItsParent()
     bottomOfItsParent()
     leftOfItsParent()

     alignBottom(otherView, marginDp=)
     alignTop(otherView)
     alignLeft(otherView)
     alignRight(otherView)

     outOfScreen(gravitiy)  //Gravity.LEFT / Gravity.RIGHT / Gravity.TOP / Gravity.BOTTOM

     alpha(alpha)
     sameAlphaAs(otherView)
     visible()
     invisible()

     custom(object: CustomAnimExpectation(){ ... })

     originalScale()

     scale(scaleX, scaleY)
     height(height, keepRatio=, useDp=)
     width(width, keepRatio=, useDp=)
     sameScaleAs(otherView)
     sameWidthAs(otherView)
     sameHeightAs(otherView)

     marginTop(margin)
     marginBottom(margin)
     marginRight(margin)
     marginLeft(margin)

     paddingTop(padding)
     paddingBottom(padding)
     paddingRight(padding)
     paddingLeft(padding)

     textColor(textColor)
     textSize(textSize)
     backgroundAlpha(alpha)

     rotated(rotation)
     vertical(bottomOfViewAtLeft)
     atItsOriginalRotation()
}

Credits

Author: Florent Champigny

Blog : http://www.tutos-android-france.com/

Fiches Plateau Moto : https://www.fiches-plateau-moto.fr/

Forked from ExpectAnim: https://github.com/florent37/ExpectAnim

<a href="https://goo.gl/WXW8Dc"> <img alt="Android app on Google Play" src="https://developer.android.com/images/brand/en_app_rgb_wo_45.png" /> </a> <a href="https://plus.google.com/+florentchampigny"> <img alt="Follow me on Google+" src="https://raw.githubusercontent.com/florent37/DaVinci/master/mobile/src/main/res/drawable-hdpi/gplus.png" /> </a> <a href="https://twitter.com/florent_champ"> <img alt="Follow me on Twitter" src="https://raw.githubusercontent.com/florent37/DaVinci/master/mobile/src/main/res/drawable-hdpi/twitter.png" /> </a> <a href="https://fr.linkedin.com/in/florentchampigny"> <img alt="Follow me on LinkedIn" src="https://raw.githubusercontent.com/florent37/DaVinci/master/mobile/src/main/res/drawable-hdpi/linkedin.png" /> </a>

License

Copyright 2018 florent37, Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

Contributors

Showing top 3 contributors by commit count.

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This article is auto-generated from florent37/KotlinPleaseAnimate via the GitHub API.Last fetched: 6/20/2026