Android仿视频加载旋转小球动画效果的实例代码

先上个效果图，以免大家跑错地了。

嗯，除了只能录三秒，其他没啥问题。

下面分析一下怎么实现上面这个效果。

理性分析后我们可以看到是几个小球绕着一个圆进行运动，那这里面的重点我们看看什么。

绘制五个球，没什么难度，让球绕圆进行运动，这个好像我们没有见到是怎么去实现了，那下就说这个。

从本质上看，球绕圆运动，其实我们可以看作是一个物体绕指定的路劲运动，那我们就有下面几个东西需要说一下：

1：Path
2：ValueAnimator
3：PathMeasure

前两个大家应该都见过，一个是路径，就是可以自己绘制路线的一个工具，一个是动画，用来指定物体运动的工具，那第三个是一个关于测量路径的类。

下面说说PathMeasure的用法。

首先是初始化：

pathMeasure = new PathMeasure(path, false);  

两个参数第一个，第一个就是我们需要用到的路径，第二个参数意思就是这个以路径头尾是否相连来计算结果，通常我们就写false就行，不会有问题。

然后是用法：

private float[] mCurrentPositionOne = new float[2];
float value = (Float)
animation.getAnimatedValue();
pathMeasure.getPosTan(value, mCurrentPositionOne, null);
  我们可以看见把一个二维数组放到了getPosTan这个方法里面，然后还有一个animation，这里的animation来自哪里呢？来自这里：valueAnimatorOne.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
  @Override
  public void onAnimationUpdate(ValueAnimator animation) {
    // 获取当前点坐标封装到mCurrentPosition
    float value = (Float) animation.getAnimatedValue();
    pathMeasure.getPosTan(value, mCurrentPositionOne, null);
    postInvalidate();
  }
});

看见没，是动画的监听里面来的，getPosTan的最后一个参数通常也就写null就行了，那么这整个一行的代码意思就是当动画发生了变化，就执行这行代码，然后这行代码会把这个时间点的路径上的坐标赋值给mCurrentPositionOne。

那我们获取到看这个路径上的坐标点怎么办呢？

立马用来ondraw里面啊，我的小球此时就可以根据这个坐标点去绘制自己的位置，这个的话，当动画开始时，小球就会不断接受新的坐标，然后不断重绘，最终产生旋转小球的效果。

我先把属性动画的代码贴出来：

if (valueAnimatorOne == null) {
   valueAnimatorOne = ValueAnimator.ofFloat(0, pathMeasure.getLength());
  valueAnimatorOne.setDuration(800);
  // 减速插值器
  valueAnimatorOne.setInterpolator(new DecelerateInterpolator());
  valueAnimatorOne.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
    @Override
    public void onAnimationUpdate(ValueAnimator animation) {
      // 获取当前点坐标封装到mCurrentPosition
      float value = (Float) animation.getAnimatedValue();
      pathMeasure.getPosTan(value, mCurrentPositionOne, null);
      postInvalidate();
    }
  });
  valueAnimatorOne.addListener(new Animator.AnimatorListener() {
    @Override
    public void onAnimationStart(Animator animator) {
      finishAnimateOne = 1;
    }
    @Override
    public void onAnimationEnd(Animator animator) {
      finishAnimateOne = 0;
    }
    @Override
    public void onAnimationCancel(Animator animator) {
    }
    @Override
    public void onAnimationRepeat(Animator animator) {
    }
  });
}
valueAnimatorOne.start();

我写了个800，也就是动画的维持时间，但是我们发现有啊后几个小球，所以我们需要绘制好几个小球，然后给他们不同的动画，为什么呢？因为动画都一样，小球就叠加在一起了，我们就只能看见一个球了。

说到这里的话，我们的目标算时完成了，具体的操作，大家参考以下代码，或者去：android自定义View索引

里面动画的demo进行下载，大家随意，下面给出代码：

/**

 * 仿视频加载动画，旋转的蓝色小球
 */
public class RotaryBall extends View {
  private Path rotationPath;
  private float radius;
  private Paint circlePaintOne;
  private PathMeasure pathMeasure;
  private int finishAnimateOne = 0;  // 用来判断当前动画有没有开始
  private int finishAnimateTwo = 0;  // 用来判断当前动画有没有开始
  private int finishAnimateThree = 0;  // 用来判断当前动画有没有开始
  private int finishAnimateFour = 0;  // 用来判断当前动画有没有开始
  private int finishAnimateFive = 0;  // 用来判断当前动画有没有开始
  private Handler handler;
  private float[] mCurrentPositionOne = new float[2];
  private float[] mCurrentPositionTwo = new float[2];
  private float[] mCurrentPositionThree = new float[2];
  private float[] mCurrentPositionFour = new float[2];
  private float[] mCurrentPositionFive = new float[2];
  private ValueAnimator valueAnimatorOne = null;
  private ValueAnimator valueAnimatorTwo = null;
  private ValueAnimator valueAnimatorThree = null;
  private ValueAnimator valueAnimatorFour = null;
  private ValueAnimator valueAnimatorFive = null;
  private int currentStatus = -1;  //-1表示第一次运行，0表示动画结束或者没开始，1表示正在运动中
  private boolean animateOrNot = true;  //用来决定是否开启动画
  public RotaryBall(Context context) {
    super(context);
    initData();
  }
  public RotaryBall(Context context, AttributeSet attrs) {
    super(context, attrs);
    initData();
  }
  private void initData() {
    rotationPath = new Path();
    circlePaintOne = new Paint();
    circlePaintOne.setColor(Color.BLUE);
    circlePaintOne.setAntiAlias(true);
    handler = new Handler() {
      @Override
      public void handleMessage(Message msg) {
        super.handleMessage(msg);
        switch (msg.what) {
          case 4:
            if (finishAnimateOne == 0) {
              startAnimatorOne();
            }
            if (finishAnimateTwo == 0) {
              startAnimatorTwo();
            }
            if (finishAnimateThree == 0) {
              startAnimatorThree();
            }
            if (finishAnimateFour == 0) {
              startAnimatorFour();
            }
            if (finishAnimateFive == 0) {
              startAnimatorFive();
            }
            currentStatus = 0;
        }
      }
    };
  }
  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    radius = getMeasuredWidth() / 2;
  }
  @Override
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
//    rotationPath.addCircle(radius, radius, radius - 10, CW);
    rotationPath.moveTo(radius, 0 + 10);
    rotationPath.cubicTo(radius, 0 + 10, radius * 2 - 10, 0 + 10, radius * 2 - 10, radius);
    rotationPath.cubicTo(radius * 2 - 10, radius, radius * 2 - 10, radius * 2 - 10, radius, radius * 2 - 10);
    rotationPath.cubicTo(radius, radius * 2 - 10, 0 + 10, radius * 2 - 10, 0 + 10, radius);
    rotationPath.cubicTo(0 + 10, radius, 0 + 10, 0 + 10, radius, 0 + 10);
    rotationPath.close();
    pathMeasure = new PathMeasure(rotationPath, false);
    //下面绘制不同半径的小圆
    canvas.drawCircle(mCurrentPositionOne[0], mCurrentPositionOne[1], 10, circlePaintOne);
    canvas.drawCircle(mCurrentPositionTwo[0], mCurrentPositionTwo[1], 9, circlePaintOne);
    canvas.drawCircle(mCurrentPositionThree[0], mCurrentPositionThree[1], 7, circlePaintOne);
    canvas.drawCircle(mCurrentPositionFour[0], mCurrentPositionFour[1], 5, circlePaintOne);
    canvas.drawCircle(mCurrentPositionFive[0], mCurrentPositionFive[1], 3, circlePaintOne);
    if (currentStatus == -1) {
      Message message = new Message();
      message.what = 4;
      handler.sendMessage(message);
    }
    if (animateOrNot) {
      if (currentStatus == 0) {
        currentStatus = 1;
        new Thread() {      //用线程来统一五个圆的周期
          @Override
          public void run() {
            super.run();
            try {
              Log.d("thread", "thread");
              Thread.sleep(1600);
              Message message = new Message();
              message.what = 4;
              handler.sendMessage(message);
            } catch (InterruptedException e) {
              e.printStackTrace();
            }
          }
        }.start();
      }
    }
  }
  //供外部调用，开始动画
  public void startAnimate() {
    if (!animateOrNot) {
      animateOrNot = true;
      currentStatus = -1;
      invalidate();
    }
  }
  //供外部调用，停止动画
  public void stopAnimate() {
    if (animateOrNot) {
      animateOrNot = false;
    }
  }
  //界面被销毁
  @Override
  protected void onDetachedFromWindow() {
    super.onDetachedFromWindow();
    stopAnimate();
    clearAllAnimation();
  }
  //清除所有动画效果
  private void clearAllAnimation() {
    if (valueAnimatorOne != null){
      if (valueAnimatorOne.isRunning()){
        valueAnimatorOne.cancel();
      }
      valueAnimatorOne.removeAllUpdateListeners();
      valueAnimatorOne = null;
    }
    if (valueAnimatorTwo != null){
      if (valueAnimatorTwo.isRunning()){
        valueAnimatorTwo.cancel();
      }
      valueAnimatorTwo.removeAllUpdateListeners();
      valueAnimatorTwo = null;
    }
    if (valueAnimatorThree != null){
      if (valueAnimatorThree.isRunning()){
        valueAnimatorThree.cancel();
      }
      valueAnimatorThree.removeAllUpdateListeners();
      valueAnimatorThree = null;
    }
    if (valueAnimatorFour != null){
      if (valueAnimatorFour.isRunning()){
        valueAnimatorFour.cancel();
      }
      valueAnimatorFour.removeAllUpdateListeners();
      valueAnimatorFour = null;
    }
    if (valueAnimatorFive != null){
      if (valueAnimatorFive.isRunning()){
        valueAnimatorFive.cancel();
      }
      valueAnimatorFive.removeAllUpdateListeners();
      valueAnimatorFive = null;
    }
  }
  //开始第一个小球的动画
  private void startAnimatorOne() {
    if (valueAnimatorOne == null) {
      Log.d("valueAnimatorOne", "valueAnimatorOne");
      valueAnimatorOne = ValueAnimator.ofFloat(0, pathMeasure.getLength());
      valueAnimatorOne.setDuration(800);
      // 减速插值器
      valueAnimatorOne.setInterpolator(new DecelerateInterpolator());
      valueAnimatorOne.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator animation) {
          // 获取当前点坐标封装到mCurrentPosition
          float value = (Float) animation.getAnimatedValue();
          pathMeasure.getPosTan(value, mCurrentPositionOne, null);
          postInvalidate();
        }
      });
      valueAnimatorOne.addListener(new Animator.AnimatorListener() {
        @Override
        public void onAnimationStart(Animator animator) {
          finishAnimateOne = 1;
        }
        @Override
        public void onAnimationEnd(Animator animator) {
          finishAnimateOne = 0;
        }
        @Override
        public void onAnimationCancel(Animator animator) {
        }
        @Override
        public void onAnimationRepeat(Animator animator) {
        }
      });
    }
    valueAnimatorOne.start();
  }
  //开始第二个小球的动画
  private void startAnimatorTwo() {
    if (valueAnimatorTwo == null) {
      valueAnimatorTwo = ValueAnimator.ofFloat(0, pathMeasure.getLength());
      valueAnimatorTwo.setDuration(1000);
      // 减速插值器
      valueAnimatorTwo.setInterpolator(new DecelerateInterpolator());
      valueAnimatorTwo.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator animation) {
          float value = (Float) animation.getAnimatedValue();
          // 获取当前点坐标封装到mCurrentPosition
          pathMeasure.getPosTan(value, mCurrentPositionTwo, null);
          postInvalidate();
        }
      });
      valueAnimatorTwo.addListener(new Animator.AnimatorListener() {
        @Override
        public void onAnimationStart(Animator animator) {
          finishAnimateTwo = 1;
        }
        @Override
        public void onAnimationEnd(Animator animator) {
          finishAnimateTwo = 0;
        }
        @Override
        public void onAnimationCancel(Animator animator) {
        }
        @Override
        public void onAnimationRepeat(Animator animator) {
        }
      });
    }
    valueAnimatorTwo.start();
  }
  //开始第三个小球的动画
  private void startAnimatorThree() {
    if (valueAnimatorThree == null) {
      valueAnimatorThree = ValueAnimator.ofFloat(0, pathMeasure.getLength());
      valueAnimatorThree.setDuration(1200);
      // 减速插值器
      valueAnimatorThree.setInterpolator(new DecelerateInterpolator());
      valueAnimatorThree.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator animation) {
          float value = (Float) animation.getAnimatedValue();
          // 获取当前点坐标封装到mCurrentPosition
          pathMeasure.getPosTan(value, mCurrentPositionThree, null);
          postInvalidate();
        }
      });
      valueAnimatorThree.addListener(new Animator.AnimatorListener() {
        @Override
        public void onAnimationStart(Animator animator) {
          finishAnimateThree = 1;
        }
        @Override
        public void onAnimationEnd(Animator animator) {
          finishAnimateThree = 0;
        }
        @Override
        public void onAnimationCancel(Animator animator) {
        }
        @Override
        public void onAnimationRepeat(Animator animator) {
        }
      });
    }
    valueAnimatorThree.start();
  }
  //开始第四个小球的动画
  private void startAnimatorFour() {
    if (valueAnimatorFour == null) {
      valueAnimatorFour = ValueAnimator.ofFloat(0, pathMeasure.getLength());
      valueAnimatorFour.setDuration(1400);
      // 减速插值器
      valueAnimatorFour.setInterpolator(new DecelerateInterpolator());
      valueAnimatorFour.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator animation) {
          float value = (Float) animation.getAnimatedValue();
          // 获取当前点坐标封装到mCurrentPosition
          pathMeasure.getPosTan(value, mCurrentPositionFour, null);
          postInvalidate();
        }
      });
      valueAnimatorFour.addListener(new Animator.AnimatorListener() {
        @Override
        public void onAnimationStart(Animator animator) {
          finishAnimateFour = 1;
        }
        @Override
        public void onAnimationEnd(Animator animator) {
          finishAnimateFour = 0;
        }
        @Override
        public void onAnimationCancel(Animator animator) {
        }
        @Override
        public void onAnimationRepeat(Animator animator) {
        }
      });
    }
    valueAnimatorFour.start();
  }
  //开始第五个小球的动画
  private void startAnimatorFive() {
    if (valueAnimatorFive == null) {
      valueAnimatorFive = ValueAnimator.ofFloat(0, pathMeasure.getLength());
      valueAnimatorFive.setDuration(1600);
      // 减速插值器
      valueAnimatorFive.setInterpolator(new DecelerateInterpolator());
      valueAnimatorFive.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator animation) {
          float value = (Float) animation.getAnimatedValue();
          // 获取当前点坐标封装到mCurrentPosition
          pathMeasure.getPosTan(value, mCurrentPositionFive, null);
          postInvalidate();
        }
      });
      valueAnimatorFive.addListener(new Animator.AnimatorListener() {
        @Override
        public void onAnimationStart(Animator animator) {
          finishAnimateFive = 1;
        }
        @Override
        public void onAnimationEnd(Animator animator) {
          finishAnimateFive = 0;
        }
        @Override
        public void onAnimationCancel(Animator animator) {
        }
        @Override
        public void onAnimationRepeat(Animator animator) {
        }
      });
    }
    valueAnimatorFive.start();
  }
}

总结

以上所述是小编给大家介绍的Android仿视频加载旋转小球动画实例代码，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对我们网站的支持！