Yet Another View Animation ( a simple and elegant view animation helper library for Android)
This library helps you convert any curve into ready-to-use Interpolator or TypeEvaluator for ValueAnimator, and thirty Rovert Penner's Easing Functions are already included.
You may read the following three articles to know about the reason why I create this project, and how to implement it. They fully described the relations among ValueAnimator、TypeEvaluator and TimeInterpolator, hope it helps.
When Math Meets Animation(1)
When Math Meets Animation(2)
When Math Meets Animation(3)
For example, if you want to create a BOUNCE_OUT animation, you can directly use EasingFunction.BOUNCE_OUT as Interpolator or TypeEvaluator for your ValueAnimator.
Option 1: use LinearInterpolator with EasingFunction.BOUNCE_OUT (as TypeEvaluator)
ObjectAnimator animator1 = new ObjectAnimator();
animator1.setTarget(textView1);
animator1.setPropertyName("translationY");
animator1.setFloatValues(0f, -100f);
animator1.setDuration(1000);
animator1.setInterpolator(new LinearInterpolator());
animator1.setEvaluator(EasingFunction.BOUNCE_OUT); //use `EasingFunction.BOUNCE_OUT` as `TypeEvaluator`
animator1.start();Option 2: use EasingFunction.BOUNCE_OUT (as Interpolator) with FloatEvaluator ("Linear TypeEvaluator")
ObjectAnimator animator2 = new ObjectAnimator();
animator2.setTarget(textView2);
animator2.setPropertyName("translationY");
animator2.setFloatValues(0f, -100f);
animator2.setDuration(1000);
animator2.setInterpolator(EasingFunction.BOUNCE_OUT); //use `EasingFunction.BOUNCE_OUT` as `Interpolator`
animator2.setEvaluator(new FloatEvaluator());
animator2.start();Want to use your customized function curve? It's simple!
Try Functions.with(IFunction youFunctionImplementation)!
Example 1: use it as TypeEvaluator
ObjectAnimator animator1 = new ObjectAnimator();
animator1.setTarget(textView1);
animator1.setPropertyName("translationY");
animator1.setFloatValues(0f, -100f);
animator1.setDuration(1000);
animator1.setInterpolator(new LinearInterpolator());
animator1.setEvaluator(Functions.with(new IFunction() { //customized TypeEvaluator
@Override
public float getValue(float input) {
return input * 2 + 3;
}
}));
animator1.start();Or you can also use it as Interpolator:
ObjectAnimator animator2 = new ObjectAnimator();
animator2.setTarget(textView2);
animator2.setPropertyName("translationY");
animator2.setFloatValues(0f, -100f);
animator2.setDuration(1000);
animator2.setInterpolator(Functions.with(new IFunction() { //customized Interpolator
@Override
public float getValue(float input) {
return input * 2 + 3;
}
}));
animator2.setEvaluator(new FloatEvaluator());
animator2.start();Copy those four classes into your project, then you are set!
OR
1.add this in your build.gradle file in root project
allprojects {
repositories {
...
maven { url "https://www.jitpack.io" }
}
}
2.add the following dependency
dependencies {
compile 'com.github.hujiaweibujidao:yava:1.0.0'
}
There are only four core classes in library.
(1) IFunction: interface
/**
* Function Interface: given input, get the value result
*/
public interface IFunction {
float getValue(float input);
}(2)AbstractFunction: abstract class
/**
* abstract function, you can use it as `Interpolator` or `TypeEvaluator`
*/
public abstract class AbstractFunction implements IFunction, Interpolator, TypeEvaluator<Float> {
@Override
public float getInterpolation(float input) {
return getValue(input);
}
@Override
public Float evaluate(float fraction, Float startValue, Float endValue) {
return startValue + getValue(fraction) * (endValue - startValue);
}
}(3)Functions: class
/**
* convert any function curve to ready-to-use AbstractFunction
*/
class Functions {
public static AbstractFunction with(final IFunction function) {
return new AbstractFunction() {
@Override
public float getValue(float input) {
return function.getValue(input);
}
};
}
}(4)EasingFunction: enum with thirty Rovert Penner's Easing Functions included
/**
* thirty Rovert Penner's Easing Functions
*/
public enum EasingFunction implements IFunction, Interpolator, TypeEvaluator<Float> {
/* ------------------------------------------------------------------------------------------- */
/* BACK
/* ------------------------------------------------------------------------------------------- */
BACK_IN {
@Override
public float getValue(float input) {
return input * input * ((1.70158f + 1) * input - 1.70158f);
}
},
BACK_OUT {
@Override
public float getValue(float input) {
return ((input = input - 1) * input * ((1.70158f + 1) * input + 1.70158f) + 1);
}
},
BACK_INOUT {
@Override
public float getValue(float input) {
float s = 1.70158f;
if ((input *= 2) < 1) {
return 0.5f * (input * input * (((s *= (1.525f)) + 1) * input - s));
}
return 0.5f * ((input -= 2) * input * (((s *= (1.525f)) + 1) * input + s) + 2);
}
},
//other easing functions ......
private float duration = 1000f;
public float getDuration() {
return duration;
}
public EasingFunction setDuration(float duration) {
this.duration = duration;
return this;
}
@Override
public float getInterpolation(float input) {
return getValue(input);
}
@Override
public Float evaluate(float fraction, Float startValue, Float endValue) {
return startValue + getValue(fraction) * (endValue - startValue);
}
//Math constants
public static final float PI = (float) Math.PI;
public static float TWO_PI = PI * 2.0f;
public static float HALF_PI = PI * 0.5f;
}1.EaseInterpolator
2.AnimationEasingFunctions
3.easings.net
Currently I'm planning to build another fancy animation library named wava for Android, follow that project or my Github if you have any interest in it. 😄
The MIT License (MIT)
Copyright (c) 2016 Hujiawei
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