Android动画总结 (valueAnimator、objectAnimator、AnimatorSet、PropertyValuesHolder、Interpolator)

参考官方文档:https://developer.android.com/guide/topics/graphics/prop-animation#api-overview

概述

笔者近期接触到android动画,将诸多概念都稍微整理了一下。
一方面做一个知识的记录,另一方面也给刚接触android动画的初学者一个参考。

主要内容

  1. ValueAnimator
  2. ObjectAnimator(包括AnimatorSet,PropertyValuesHolder)
  3. AnimatorSet 和 PropertyValuesHolder
  4. 插值器(Interpolator)

valueAnimator

valueAnimator可以控制某个值的变化,通过在值变化的同时刷新View来实现动画。
下面的例子是实现TextView中值的刷新:

        ValueAnimator valueAnimator = ValueAnimator.ofInt(0, 1000);
        valueAnimator.setDuration(5000);
        valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                tv1.setText(animation.getAnimatedValue() + "");
            }
        });
        valueAnimator.start();

ObjectAnimator

ObjectAnimator可以对某个View执行属性动画,常见的属性动画有旋转,平移,缩放等。
ObjectAnimator一般是配合着AnimatorSet或者PropertyValuesHolder使用,demo如下,以下两块代码实现的是同一种效果:“btn先放大后缩小”。

属性动画有以下几种:(来自官方文档)

  • translationX,translationY:从当前位置开始平移
  • rotation, rotationX, rotationY:旋转
  • scaleX , scaleY:缩放
  • pivotX , pivotY:旋转和缩放的参照点,默认是View的中心
  • x , y:平移到当前容器的某个绝对位置
  • alpha:透明度
		/*
          ObjectAnimator + PropertyValuesHolder
         */
        PropertyValuesHolder xHolder = PropertyValuesHolder.ofFloat("scaleX", 1, 1.5f, 0.8f, 1);
        PropertyValuesHolder yHolder = PropertyValuesHolder.ofFloat("scaleY", 1, 1.5f, 0.8f, 1);
        ObjectAnimator objectAnimator = ObjectAnimator.ofPropertyValuesHolder(btn0, xHolder, yHolder);
        objectAnimator.setDuration(3000);
        objectAnimator.start();

        /*
         * ObjectAnimator + AnimatorSet
         */
        ObjectAnimator anim1 = ObjectAnimator.ofFloat(btn1, "scaleX", 1, 1.5f, 0.8f, 1);
        ObjectAnimator anim2 = ObjectAnimator.ofFloat(btn1, "scaleY", 1, 1.5f, 0.8f, 1);
        final AnimatorSet animatorSet = new AnimatorSet();
        animatorSet.play(anim1);
        animatorSet.play(anim2).with(anim1);
        animatorSet.setDuration(3000);
        animatorSet.start();

AnimatorSet 和 PropertyValuesHolder

PropertyValuesHolder:

适合在实现“单个View连续动画”的情况下使用,使用AnimatorSet在一些情况下会比PropertyValuesHolder复杂一些。
比如要实现View的循环播放,使用PropertyValuesHolder实现的代码如下:

		objectAnimator.setRepeatCount(-1);

使用AnimatorSet实现的代码如下:

		animatorSet.addListener(new Animator.AnimatorListener() {
            @Override
            public void onAnimationStart(Animator animation) {

            }

            @Override
            public void onAnimationEnd(Animator animation) {
                if (animatorSet != null) {
                    animatorSet.start();
                }
            }

            @Override
            public void onAnimationCancel(Animator animation) {

            }

            @Override
            public void onAnimationRepeat(Animator animation) {

            }
        });

AnimatorSet

适合在动画比较复杂的情况下使用,比如有多个View的动画需要同时进行或者交替进行,这种情况使用PropertyValuesHolder是很难实现的。
再比如,对于同一个View的动画不连续的情况,PropertyValuesHolder也比较难实现,或者说实现更加复杂。
demo中,View执行完平移之后再执行缩放逻辑。

		ObjectAnimator anim11 = ObjectAnimator.ofFloat(tv2, "translationX", 200);
        ObjectAnimator anim22 = ObjectAnimator.ofFloat(tv2, "scaleX", 1, 1.5f, 1f);
        ObjectAnimator anim33 = ObjectAnimator.ofFloat(tv2, "scaleY", 1, 1.5f, 1f);
        final AnimatorSet animatorSet2 = new AnimatorSet();
        animatorSet2.play(anim11);
        animatorSet2.play(anim22).after(anim11);
        animatorSet2.play(anim33).with(anim22);
        animatorSet2.setDuration(3000);
        animatorSet2.start();

插值器(Interpolator)

插值器可以控制动画变化的速率,设置非常简单,代码如下:

        ValueAnimator valueAnimator = ValueAnimator.ofInt(0, 1000);
        valueAnimator.setDuration(5000);
        valueAnimator.setInterpolator(new DecelerateInterpolator());//设置插值器
        valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                tv1.setText(animation.getAnimatedValue() + "");
            }
        });
        valueAnimator.start();

插值器类型:(来自官方文档)

  • AccelerateDecelerateInterpolator:开始和结束的时候慢,中间快
  • AccelerateInterpolator:开始的时候慢,然后加速
  • AnticipateInterpolator:开始先后退,然后向前
  • AnticipateOvershootInterpolator: 开始先后退,然向前到超标,最后回到最终值
  • BounceInterpolator :最后会反弹
  • CycleInterpolator:动画会重复一定的周期数
  • DecelerateInterpolator:开始快,然后减速
  • LinearInterpolator:变化匀速
  • OvershootInterpolator:到达最终值后超标,再回到最终值
  • TimeInterpolator:用来自定义插值器

demo代码:

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        LinearLayout linearLayout = new LinearLayout(this);
        linearLayout.setOrientation(LinearLayout.VERTICAL);
        setContentView(linearLayout);

        // test View
        final TextView tv1 = new TextView(this);
        tv1.setText(0 + "");
        tv1.setTextSize(30);
        linearLayout.addView(tv1);
        final Button btn0 = new Button(this);
        btn0.setText("btn0");
        linearLayout.addView(btn0);
        final Button btn1 = new Button(this);
        btn1.setText("btn1");
        linearLayout.addView(btn1);
        final TextView tv2 = new TextView(this);
        tv2.setText("tv2");
        tv2.setTextSize(30);
        linearLayout.addView(tv2);
        final Button btn2 = new Button(this);
        btn2.setText("btn2");
        linearLayout.addView(btn2);
        final Button btn3 = new Button(this);
        btn3.setText("btn3");
        linearLayout.addView(btn3);


        /*
         * ValueAnimator  +时间插值器演示
         */
        ValueAnimator valueAnimator = ValueAnimator.ofInt(0, 1000);
        valueAnimator.setDuration(5000);
        valueAnimator.setInterpolator(new DecelerateInterpolator());//设置插值器
        valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                tv1.setText(animation.getAnimatedValue() + "");
            }
        });
        valueAnimator.start();

        /*
          ObjectAnimator + PropertyValuesHolder
         */
        PropertyValuesHolder xHolder = PropertyValuesHolder.ofFloat("scaleX", 1, 1.5f, 0.8f, 1);
        PropertyValuesHolder yHolder = PropertyValuesHolder.ofFloat("scaleY", 1, 1.5f, 0.8f, 1);
        ObjectAnimator objectAnimator = ObjectAnimator.ofPropertyValuesHolder(btn0, xHolder, yHolder);
        objectAnimator.setDuration(3000);
//        objectAnimator.setRepeatCount(-1);
        objectAnimator.start();

        /*
         * ObjectAnimator + AnimatorSet
         */
        ObjectAnimator anim1 = ObjectAnimator.ofFloat(btn1, "scaleX", 1, 1.5f, 0.8f, 1);
        ObjectAnimator anim2 = ObjectAnimator.ofFloat(btn1, "scaleY", 1, 1.5f, 0.8f, 1);
        final AnimatorSet animatorSet = new AnimatorSet();
        animatorSet.play(anim1);
        animatorSet.play(anim2).with(anim1);
        animatorSet.setDuration(3000);
        animatorSet.addListener(new Animator.AnimatorListener() {
            @Override
            public void onAnimationStart(Animator animation) {

            }

            @Override
            public void onAnimationEnd(Animator animation) {
                if (animatorSet != null) {
                    animatorSet.start();
                }
            }

            @Override
            public void onAnimationCancel(Animator animation) {

            }

            @Override
            public void onAnimationRepeat(Animator animation) {

            }
        });
        animatorSet.start();

        /*
         * ObjectAnimator + AnimatorSet
         */
        ObjectAnimator anim11 = ObjectAnimator.ofFloat(tv2, "translationX", 200);
        ObjectAnimator anim22 = ObjectAnimator.ofFloat(tv2, "scaleX", 1, 1.5f, 1f);
        ObjectAnimator anim33 = ObjectAnimator.ofFloat(tv2, "scaleY", 1, 1.5f, 1f);
        final AnimatorSet animatorSet2 = new AnimatorSet();
        animatorSet2.play(anim11);
        animatorSet2.play(anim22).after(anim11);
        animatorSet2.play(anim33).with(anim22);
        animatorSet2.setDuration(3000);
        animatorSet2.start();

    }

}

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