[移动开发]Android 属性动画Animator

做个记录，之前项目中用得比较少
一、Activity中代码段

 /**
     * 动态生成ValueAnimator
     * 执行后不断改变view得最小宽度
     */
    private fun animationBigger() {
        //属性从300递增到500
        val anim = ValueAnimator.ofInt(300, 400).apply {
            this.duration = 2000 //执行时长
            this.repeatCount = 0
            this.repeatMode = ValueAnimator.RESTART
        }
        anim.addUpdateListener {
            // 获得改变后的值
            val currentValue = it.animatedValue as Int
            // 步骤4：将改变后的值赋给对象的属性值，下面会详细说明
            binding.btn1.minWidth = currentValue
            // 步骤5：刷新视图，即重新绘制，从而实现动画效果
            binding.btn1.requestLayout();
        }
        anim.addListener(object : Animator.AnimatorListener {
            override fun onAnimationStart(animation: Animator?) {
            }

            override fun onAnimationEnd(animation: Animator?) {
                startAnimset()
            }

            override fun onAnimationCancel(animation: Animator?) {
            }

            override fun onAnimationRepeat(animation: Animator?) {
            }
        })
        anim.start()//开始执行动画
        startAnimXml()
    }

    /**
     * 动态生成ObjectAnimator，AnimatorSet
     * 执行：沿Y轴旋转后位移300
     */
    private fun startAnimset() {
        val anim = ObjectAnimator.ofFloat(binding.btn1, "translationX", 0f, 300f)
        val animRotate = ObjectAnimator.ofFloat(binding.btn1, "rotationY", 0f, 360f)
        val animatorSet = AnimatorSet()
        animatorSet.playSequentially(anim)
        animatorSet.duration = 2000
        //通过animatorSet的play方法获取  感兴趣的话 可以都试试 看一下效果
        animatorSet.play(anim).after(animRotate)
        /**
         * 系统自带BounceInterpolator，AccelerateInterpolator加速，DecelerateInterpolator减速，LinearInterpolator匀速
         * CycleInterpolator(0.5f)来回,OvershootInterpolator
         * http://inloop.github.io/interpolator/ 插值器示例
         */
        animatorSet.interpolator = MInterpolator(0.5f)//自定义插值器
//        animatorSet.interpolator = CycleInterpolator(0.5f)
//        animatorSet.interpolator = OvershootInterpolator(2.0f)

        animatorSet.addListener(object : Animator.AnimatorListener {
            override fun onAnimationStart(animation: Animator?) {
            }

            override fun onAnimationEnd(animation: Animator?) {
//                translate()//重复执行
            }

            override fun onAnimationCancel(animation: Animator?) {
            }

            override fun onAnimationRepeat(animation: Animator?) {
            }
        })

        animatorSet.start()
    }

    private var startTime = 0L

    /**
     * 根据静态文件生成Animator
     * 执行：旋转后位移
     * 注意：静态文件配置得duration并不完全生效（有一定得效果）
     */
    private fun startAnimXml() {
        AnimatorInflater.loadAnimator(this, R.animator.anim_first).apply {
            this.setTarget(binding.text)
            this.interpolator = LinearInterpolator()
//            this.startDelay = 5000//start后延迟5秒执行
//            this.duration = 10000;//生效
            this.addListener(object : Animator.AnimatorListener {
                override fun onAnimationStart(animation: Animator?) {
                    startTime = System.currentTimeMillis()
                    "开始执行".d()
                }

                override fun onAnimationEnd(animation: Animator?) {
                    "timelong=${(System.currentTimeMillis() - startTime)}".d()
                }

                override fun onAnimationCancel(animation: Animator?) {
                }

                override fun onAnimationRepeat(animation: Animator?) {
                }
            })
        }.start()
    }

二、自定义插值器

import android.animation.TimeInterpolator
import kotlin.math.pow
import kotlin.math.sin

/**
 * @author Liushihua
 * @date 2022-5-17 16:51
 * @desc
 */
class MInterpolator(var factor: Float = 0.15f) : TimeInterpolator {
    // 因子数值越小振动频率越高
    override fun getInterpolation(input: Float): Float {
        return (2.0.pow(-10 * input.toDouble()) * sin((input - factor / 4) * (2 * Math.PI) / factor) + 1).toFloat()
    }
}

三、values中新建animator文件夹，anim_first.xml

<set xmlns:android="http://schemas.android.com/apk/res/android"
    android:ordering="sequentially">
    <!-- sequentially按顺序执行 together同时执行 -->
    <objectAnimator
        android:duration="5000"
        android:propertyName="rotation"
        android:valueFrom="0"
        android:valueTo="360" />
    <objectAnimator
        android:duration="7000"
        android:propertyName="translationX"
        android:valueFrom="0"
        android:valueTo="560" />
</set>

参考：
https://blog.csdn.net/weixin_45558166/article/details/110310651
https://www.jianshu.com/p/39ee86df9e5a

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