仿抖音视频详情页红心动效

GitHub地址：

https://github.com/selfconzrr/LikeAnimator

核心思路：

自定义 View 继承自 RelativeLayout ，重写 onTouchEvent，在点击时触发将心形的图片 add 到整个 view 中，然后在执行动画。主要的处理逻辑都在 onTouchEvent() 事件中。

首先，我们需要在触摸事件中做监听，当有触摸时，创建一个展示心形图片的 ImageView；然后设置图片展示的位置，需要在手指触摸的位置上方，即触摸点是心形的下方角的位置；接下来设置 imageView 动画 AnimatorSet，并记住：我们不可能无限制的增加 view，在 view 消失之后，需要手动的移除改 imageView。

package com.example.zhangruirui.likeanimator;

import android.animation.Animator;
import android.animation.AnimatorListenerAdapter;
import android.animation.AnimatorSet;
import android.animation.ObjectAnimator;
import android.animation.TimeInterpolator;
import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.LinearInterpolator;
import android.widget.ImageView;
import android.widget.RelativeLayout;

import java.util.Random;

/**
 * ZhangRuirui：2018/08/31
 * 在点击时触发将心形的图片 add 到整个 view 中，然后在执行动画。主要的处理逻辑都在 onTouchEvent() 事件中
 */

public class LoveAnimator extends RelativeLayout {

  private Context mContext;
  final float[] num = {-30, -20, 0, 20, 30}; // 随机心形图片的角度

  public LoveAnimator(Context context) {
    this(context, null);
  }

  public LoveAnimator(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
  }

  public LoveAnimator(Context context, AttributeSet attrs, int defStyleAttr) {
    this(context, attrs, defStyleAttr, 0);
  }

  @SuppressLint("NewApi")
  public LoveAnimator(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
    super(context, attrs, defStyleAttr, defStyleRes);
    initView(context);
  }

  private void initView(Context context) {
    mContext = context;
  }

  @Override
  protected void dispatchDraw(Canvas canvas) {
    super.dispatchDraw(canvas);
  }

  @SuppressLint("ClickableViewAccessibility")
  @Override
  public boolean onTouchEvent(MotionEvent event) {

    // 首先，我们需要在触摸事件中做监听，当有触摸时，创建一个展示心形图片的 ImageView
    final ImageView imageView = new ImageView(mContext);

    // 设置图片展示的位置，需要在手指触摸的位置上方，即触摸点是心形的下方角的位置。所以我们需要将 ImageView 设置到手指的位置
    LayoutParams params = new LayoutParams(300, 300);
    params.leftMargin = (int) event.getX() - 150;
    params.topMargin = (int) event.getY() - 300;

    imageView.setImageDrawable(getResources().getDrawable(R.drawable.details_icon_like_pressed));
    imageView.setLayoutParams(params);
    addView(imageView);

    // 设置 imageView 动画
    AnimatorSet animatorSet = new AnimatorSet();
    animatorSet.play(scale(imageView, "scaleX", 2f, 0.9f, 100, 0)) // 缩放动画，X轴2倍缩小至0.9倍
        .with(scale(imageView, "scaleY", 2f, 0.9f, 100, 0)) // 缩放动画，Y轴2倍缩小至0.9倍
        .with(rotation(imageView, 0, 0, num[new Random().nextInt(4)])) // 旋转动画，随机旋转角度num={-30.-20，0，20，30}
        .with(alpha(imageView, 0, 1, 100, 0)) // 渐变透明度动画，透明度从0-1.
        .with(scale(imageView, "scaleX", 0.9f, 1, 50, 150)) // 缩放动画，X轴0.9倍缩小至1倍
        .with(scale(imageView, "scaleY", 0.9f, 1, 50, 150)) // 缩放动画，Y轴0.9倍缩小至1倍
        .with(translationY(imageView, 0, -600, 800, 400)) // 平移动画，Y轴从0向上移动600单位
        .with(alpha(imageView, 1, 0, 300, 400)) // 透明度动画，从1-0
        .with(scale(imageView, "scaleX", 1, 3f, 700, 400)) // 缩放动画，X轴1倍放大至3倍
        .with(scale(imageView, "scaleY", 1, 3f, 700, 400)); // 缩放动画，Y轴1倍放大至3倍
    animatorSet.start();

    // 我们不可能无限制的增加 view，在 view 消失之后，需要手动的移除改 imageView
    animatorSet.addListener(new AnimatorListenerAdapter() {
      @Override
      public void onAnimationEnd(Animator animation) {
        super.onAnimationEnd(animation);
        removeViewInLayout(imageView);
      }
    });
    return super.onTouchEvent(event);
  }

  public static ObjectAnimator scale(View view, String propertyName, float from, float to, long time, long delayTime) {
    ObjectAnimator translation = ObjectAnimator.ofFloat(view
        , propertyName
        , from, to);
    translation.setInterpolator(new LinearInterpolator());
    translation.setStartDelay(delayTime);
    translation.setDuration(time);
    return translation;
  }

  public static ObjectAnimator translationX(View view, float from, float to, long time, long delayTime) {
    ObjectAnimator translation = ObjectAnimator.ofFloat(view
        , "translationX"
        , from, to);
    translation.setInterpolator(new LinearInterpolator());
    translation.setStartDelay(delayTime);
    translation.setDuration(time);
    return translation;
  }

  public static ObjectAnimator translationY(View view, float from, float to, long time, long delayTime) {
    ObjectAnimator translation = ObjectAnimator.ofFloat(view
        , "translationY"
        , from, to);
    translation.setInterpolator(new LinearInterpolator());
    translation.setStartDelay(delayTime);
    translation.setDuration(time);
    return translation;
  }

  public static ObjectAnimator alpha(View view, float from, float to, long time, long delayTime) {
    ObjectAnimator translation = ObjectAnimator.ofFloat(view
        , "alpha"
        , from, to);
    translation.setInterpolator(new LinearInterpolator());
    translation.setStartDelay(delayTime);
    translation.setDuration(time);
    return translation;
  }

  public static ObjectAnimator rotation(View view, long time, long delayTime, float... values) {
    ObjectAnimator rotation = ObjectAnimator.ofFloat(view, "rotation", values);
    rotation.setDuration(time);
    rotation.setStartDelay(delayTime);
    rotation.setInterpolator(new TimeInterpolator() {
      @Override
      public float getInterpolation(float input) {
        return input;
      }
    });
    return rotation;
  }
}