ez_animation

ezanimation

Easy Animations - No Controllers, No Tickers, Only the necessary parts.

Easily add Curves and ReverseCurves

Introduction

Normal animations involve a fair amount of complexity: AnimationControllers, Tweens, Animation, Tickers are not familiar concepts to many. Not just to beginners - when creating an explicit animation, even advanced users experience hardships dealing with the many components involved.

Announcing EzAnimation: A set of tools to make animations easier

With EzAnimation, there is no need to burden your code with TickerProviders, the complicated logic of curves, different components of animation, etc.

Here is a simple example to create an animation with an expanding box:

1. First, we define a Container with a starting size of 50.0

   return Scaffold(
     body: Center(
       child: Container(
         color: Colors.yellow,
         height: 50.0,
         width: 50.0,
       ),
     ),
   );
   

2. Next, we define an animation to increase size

   EzAnimation ezAnimation = EzAnimation(50.0, 200.0, Duration(seconds: 2));
   

3. Then, we simply plugin in values and start the animation when we need to - in this case we will do it when the box is tapped

   return Scaffold(
     body: Center(
       child: InkWell(
         onTap: () {
           ezAnimation.start();
         },
         child: AnimatedBuilder(
           animation: ezAnimation,
           builder: (context, snapshot) {
             return Container(
               color: Colors.yellow,
               height: ezAnimation.value,
               width: ezAnimation.value,
             );
           }
         ),
       ),
     ),
   );
   

4. And that's it!

TO USE:

DEFINE EzAnimation

(RECOMMENDED METHOD 1) Passing context:

EzAnimation animation = EzAnimation(10.0, 100.0, Duration(seconds: 1), context: context);

// This animation needs to be manually restarted when another page is pushed and then Navigator comes back
// The onNavigate param helps define the behaviour when another page is pushed

(RECOMMENDED METHOD 2) Passing vsync:

EzAnimation animation = EzAnimation(10.0, 100.0, Duration(seconds: 1), context: context);

// Here the state class needs to add SingleTickerProviderMixin or TickerProviderMixin
// onNavigate does not work in this case as the page ticker defines the state of the animation

A SIMPLE METHOD (LESS PERFORMANT): No context or vsync

EzAnimation animation = EzAnimation(10.0, 100.0, Duration(seconds: 1));

// Note that this animation needs to be manually stopped if you intend to push another page as it will go to completion without it.

(Notice that you can define this outside of initState, unlike normal animation controllers)

START ANIMATION

animation.start();

// OR

animation.start(from: 0.2);

END ANIMATION

animation.stop();

REPEAT ANIMATION

animation.repeat();

RESET ANIMATION

animation.reset();

REVERSE ANIMATION

animation.reverse();

// OR

animation.reverse(from: 0.5);

DEFINE WHAT HAPPENS WHEN NAVIGATOR PUSHES ANOTHER PAGE ON TOP

EzAnimation animation = EzAnimation(10.0, 100.0, Duration(seconds: 1), context: context, onNavigate: OnNavigate.pauseAnimation);

An animation can either reset or pause when the navigator pushes another page on top. Use the onNavigate page to achieve this.

NOTE: A PAUSED ANIMATION NEEDS TO BE MANUALLY RESTARTED AFTER COMING BACK TO THE MAIN PAGE

onPressed: () async {
    await Navigator.of(context).push(MaterialPageRoute(builder: (context) => DemoPage()));
    animation.start();
}

resetAnimation -> Resets animation to the start
pauseAnimation -> Pauses animation at that instant (You need to manually restart this when it comes back)
letItRun -> Animation will go to completion unless animation.stop() is called.
takeToEnd -> Takes animation to final value instantly

REBUILD UI

You can use normal listeners and rebuild UI with AnimatedBuilder as usual.

animation.addListener(() { 
  setState(() {});
});

//OR

AnimatedBuilder(
    animation: animation,
    builder: (context, snapshot) {
      return Center(
        child: Container(
          width: animation.value,
          height: animation.value,
          color: Colors.blue,
        ),
      );
    }
  ),

ADD CURVES EASILY

var animation = EzAnimation(10.0, 100.0, Duration(seconds: 1), curve: Curves.bounceInOut, reverseCurve: Curves.linear);

LISTEN TO STATUS

animation.addStatusListener((status) {
  if (status == AnimationStatus.completed) {
    animation.reverse();
  }
});

USE ANIMATION SEQUENCES

You can have multiple animations running in series with weights with EzAnimation.sequence()

EzAnimation ezAnimation = EzAnimation.sequence([
  SequenceItem(0.0, 100.0, weight: 2),
  SequenceItem(100.0, 50.0),
  SequenceItem(50.0, 100.0),
], Duration(seconds: 2), context: context);

ezAnimation.start();

USE SPECIALIZED TWEENS

Use the EzAnimation.tween() to pass in other Tween types such as ColorTween

EzAnimation ezAnimation = EzAnimation.tween(ColorTween(begin: Colors.red, end: Colors.blue), Duration(seconds: 2), context: context);

ezAnimation.start();

Similarly, the EzAnimation.tweenSequence allows you to create a sequence with ColorTweens and other tweens

EzAnimation ezAnimation = EzAnimation.tweenSequence(TweenSequence([
    TweenSequenceItem(tween: ColorTween(begin: Colors.red, end: Colors.blue), weight: 1.0),
    TweenSequenceItem(tween: ColorTween(begin: Colors.red, end: Colors.blue), weight: 2.0),
]), Duration(seconds: 2), context: context);