【黄啊码】安卓实现支付宝中的蚂蚁森林效果

最近公司产品突然有一个类似支付宝蚂蚁森林的功能，大致功能跟支付宝蚂蚁森林相像，在看了一下支付宝蚂蚁森林的效果之后，打算先撸一个控件出来，等公司效果图出来之后就可以放上去直接使用。
首先我们先大致看下支付宝的蚂蚁森林效果图：

这是目前我实现的效果图：

当我们拿到这个需求时先分析一波，不要忙着就动手开干，不然容易平地翻车。。
需要实现的功能有：

1、自定小圆球，圆球内文字、上下浮动、消失动画；

2、根据数据动态添加小球，并且位置随机分布在小树周围，不能重叠。这点是最重要的，涉及到一个随机位置生成算法的设计。

好了，当我们确定了我们要实现的功能之后就可以逐步开始撸代码了。

自定义圆球

这个比较容易实现，绘制一个圆，再在园内绘制文字，动画实现统一采用的是属性动画来实现，代码如下，注释写的比较详细就不一一解释了，懒...

/*** @describe: 自定义仿支付宝蚂蚁森林水滴View*/public class WaterView extends View {private Paint paint;private ObjectAnimator mAnimator;/*** 文字颜色*/private int textColor = Color.parseColor("#69c78e");/*** 水滴填充颜色*/private int waterColor = Color.parseColor("#c3f593");/*** 球描边颜色*/private int storkeColor = Color.parseColor("#69c78e");/*** 描边线条宽度*/private float strokeWidth = 0.5f;/*** 文字字体大小*/private float textSize = 36;/*** 根据远近距离的不同计算得到的应该占的半径比例*/private float proportion;/*** 水滴球半径*/private int mRadius = 30;/*** 圆球文字内容*/private String textContent="3g";public WaterView(Context context) {super(context);init();}public WaterView(Context context, @Nullable AttributeSet attrs) {super(context, attrs);init();}public WaterView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {super(context, attrs, defStyleAttr);init();}private void init() {paint = new Paint();paint.setAntiAlias(true);}@Overridepublic void draw(Canvas canvas) {super.draw(canvas);drawCircleView(canvas);}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {super.onMeasure(widthMeasureSpec, heightMeasureSpec);setMeasuredDimension(Utils.dp2px(getContext(), (int) (2 * (mRadius+strokeWidth))),Utils.dp2px(getContext(), (int) (2 * (mRadius+strokeWidth))));}@Overrideprotected void onAttachedToWindow() {super.onAttachedToWindow();start();}@Overrideprotected void onDetachedFromWindow() {super.onDetachedFromWindow();stop();}@Overrideprotected void onVisibilityChanged(@NonNull View changedView, int visibility) {super.onVisibilityChanged(changedView, visibility);if (visibility == VISIBLE) {start();} else {stop();}}private void drawCircleView(Canvas canvas){//圆球paint.setColor(waterColor);paint.setStyle(Paint.Style.FILL);canvas.drawCircle(Utils.dp2px(getContext(), mRadius), Utils.dp2px(getContext(), mRadius), Utils.dp2px(getContext(), mRadius), paint);//描边paint.setColor(storkeColor);paint.setStyle(Paint.Style.STROKE);paint.setStrokeWidth(Utils.dp2px(getContext(), (int) strokeWidth));canvas.drawCircle(Utils.dp2px(getContext(), mRadius), Utils.dp2px(getContext(), mRadius), Utils.dp2px(getContext(), (int) (mRadius+strokeWidth)) , paint);//圆球文字paint.setTextSize(textSize);paint.setColor(textColor);paint.setStyle(Paint.Style.FILL);drawVerticalText(canvas, Utils.dp2px(getContext(), mRadius), Utils.dp2px(getContext(), mRadius), textContent);}private void drawVerticalText(Canvas canvas, float centerX, float centerY, String text) {Paint.FontMetrics fontMetrics = paint.getFontMetrics();float baseLine = -(fontMetrics.ascent + fontMetrics.descent) / 2;float textWidth = paint.measureText(text);float startX = centerX - textWidth / 2;float endY = centerY + baseLine;canvas.drawText(text, startX, endY, paint);}public void start() {if (mAnimator == null) {mAnimator = ObjectAnimator.ofFloat(this, "translationY", -6.0f, 6.0f, -6.0f);mAnimator.setDuration(3500);mAnimator.setInterpolator(new LinearInterpolator());mAnimator.setRepeatMode(ValueAnimator.RESTART);mAnimator.setRepeatCount(ValueAnimator.INFINITE);mAnimator.start();} else if (!mAnimator.isStarted()) {mAnimator.start();}}public void stop() {if (mAnimator != null) {mAnimator.cancel();mAnimator = null;}}public float getProportion() {return proportion;}public void setProportion(float proportion) {this.proportion = proportion;}
}

动态随机添加小球

这里我采用的是集成FrameLayout 通过设置小球数据，动态将小球add进去，比较简便，在这里最重要是动态随机添加小球的算法，解决了这个算法就好办了。通过仔细观察支付宝蚂蚁森林的效果实现，我们可以发现一般小球都是在树的正上方随机分布的。所以我想以小树的根为中心，小树的高度为半径为一个扇形，在这个扇形上方随机摆放小球。

公式：坐标 = 旋转角度 * 半径 * 根据远近距离的不同计算得到的应该占的半径比例

圆上任一点（x1,y1）坐标的计算公式：

x1 = x0 + r * cos(ao * 3.14 /180 )

y1 = y0 + r * sin(ao * 3.14 /180 )

具体实现代码如下：

/*** @describe: 支付宝蚂蚁森林水滴能量*/public class WaterFlake extends FrameLayout {private OnWaterItemListener mOnWaterItemListener;/*** 小树坐标X*/private float treeCenterX = 0;/*** 小树坐标Y*/private float treeCenterY = 0;/*** 小树高度*/private int radius = 80;/*** 开始角度*/private double mStartAngle = 0;/*** 是否正在收集能量*/private boolean isCollect = false;public WaterFlake(@NonNull Context context) {super(context);}public WaterFlake(@NonNull Context context, @Nullable AttributeSet attrs) {super(context, attrs);}public WaterFlake(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {super(context, attrs, defStyleAttr);}@Overridepublic boolean onTouchEvent(MotionEvent event) {if (event.getAction() == MotionEvent.ACTION_DOWN) {int x = (int) event.getX();int y = (int) event.getY();Rect rect = new Rect();for (int i = 0; i < getChildCount(); i++) {getChildAt(i).getHitRect(rect);if (rect.contains(x, y)) {if (mOnWaterItemListener != null) {getChildAt(i).performClick();mOnWaterItemListener.onItemClick(i);startAnimator(getChildAt(i));return true;}}}}return super.onTouchEvent(event);}@Overridepublic boolean performClick() {return super.performClick();}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {super.onMeasure(widthMeasureSpec, heightMeasureSpec);measureChildren(widthMeasureSpec, heightMeasureSpec);}@Overrideprotected void onLayout(boolean changed, int l, int t, int r, int b) {int childCount = getChildCount();if (childCount==0){return;}int left, top;// 根据tem的个数，计算角度float angleDelay = -180 / childCount;for (int i = 0; i < childCount; i++) {WaterView child = (WaterView) getChildAt(i);mStartAngle %= 180;//设置CircleView小圆点的坐标信息//坐标 = 旋转角度 * 半径 * 根据远近距离的不同计算得到的应该占的半径比例
//            则圆上任一点为：（x1,y1）
//            x1   =   x0   +   r   *   cos(ao   *   3.14   /180   )
//            y1   =   y0   +   r   *   sin(ao   *   3.14   /180   )if (child.getVisibility() != GONE) {left = (int) (getTreeCenterX() + radius * Math.cos(mStartAngle * 3.14 / 180) * (child.getProportion() / radius * 2));top = (int) (getTreeCenterY() + radius * Math.sin(mStartAngle * 3.14 / 180) * (child.getProportion() / radius * 2));child.layout(left, top, left + child.getMeasuredWidth(), top + child.getMeasuredWidth());}mStartAngle += angleDelay;}}/*** 设置小球数据，根据数据集合创建小球数量** @param modelList 数据集合*/public void setModelList(List<WaterModel> modelList, float treeCenterX, float treeCenterY) {this.treeCenterX = treeCenterX;this.treeCenterY = treeCenterY;for (int i = 0; i < modelList.size(); i++) {WaterView waterView = new WaterView(getContext(),(i+1)+"g");waterView.setProportion(Utils.getRandom(radius, radius + 80));addView(waterView);}}/*** 设置小球点击事件** @param onWaterItemListener*/public void setOnWaterItemListener(OnWaterItemListener onWaterItemListener) {mOnWaterItemListener = onWaterItemListener;}public interface OnWaterItemListener {void onItemClick(int pos);}private void startAnimator(final View view) {if (isCollect) {return;}isCollect = true;ObjectAnimator translatAnimatorY = ObjectAnimator.ofFloat(view, "translationY", getTreeCenterY());translatAnimatorY.start();ObjectAnimator alphaAnimator = ObjectAnimator.ofFloat(view, "alpha", 1f, 0f);alphaAnimator.start();AnimatorSet animatorSet = new AnimatorSet();animatorSet.play(translatAnimatorY).with(alphaAnimator);animatorSet.setDuration(3000);animatorSet.start();animatorSet.addListener(new AnimatorListenerAdapter() {@Overridepublic void onAnimationEnd(Animator animation) {removeViewInLayout(view);isCollect = false;}});}public float getTreeCenterX() {return treeCenterX;}public float getTreeCenterY() {return treeCenterY;}
}

小球摆放随机算法有多种实现方式，这只是其中一种，写的不好的地方，还望各位指正，欢迎大家一起交流学习。

目前代码还有一些地方需要完善的，逐步更新。。。

TODO

优化小球随机生成算法，保证每个小球尽量不会重叠