作者 夏至，欢迎转载，也请保留这段申明，谢谢
http://blog.csdn.net/u011418943/article/details/73555330

最近在学习自定义view，刚好有个需求是做一个点击完成的动画，所以就运用上了，效果如下：

这里写图片描述

把动画分解出来其实很简单，步骤如下：

• 把两边的圆角变成圆
• 把长椭圆变成缩小变成一个圆，文字渐变为无，可以用setalpha属性
• 圆从底部上升并变大，这没什么好说的，改变Y轴的值即可
• 打钩，这个也比较简单，用PathMeasure画勾就可以了

完成代码在底部，下面是简单分析：

1.1 圆角转圆

这个比较简单，首先我们先用 drawRoundRect 设置好圆角，想一下，从圆角到到圆，变化的是什么？没有就 drawRoundRect 的中间两个参数，只要把它变成圆的半径大小，即 height 的一半即可。
所以，动画如下：

 //圆角变圆
        mRectToRoundAnim = ValueAnimator.ofFloat(10,mRadius);
        mRectToRoundAnim.setDuration(500);
        mRectToRoundAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator valueAnimator) {
                mRectToRound = (float) valueAnimator.getAnimatedValue();
                mStatus = 0;
                invalidate();
            }
        });

获取到mRectToRound 的值，(好吧，这个命名有问题，自己去改吧)；

1.2 长圆变圆

这个也是很简单，改变它的长度接口，那长度是多少？ 我们是让它从两边移动过来的，所以就是 （width - height）/ 2；而在变的过程中，需要对文字渐变消失，可以使用 setalpha ，从255 到 0 即可。如下所示：

//长椭圆变圆动画,并让文字渐渐消失
        mRoundToCircleAnim = ValueAnimator.ofFloat(0,(width-height)/2);
        mRoundToCircleAnim.setDuration(1000);
        mRoundToCircleAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator valueAnimator) {
                mRoundToCircleOffert = (float) valueAnimator.getAnimatedValue();
                int max = (width - height)/2 ;
                int alpha = (int) ((float)(max - mRoundToCircleOffert)/max * 255);
                mTextPaint.setAlpha(alpha);
                mStatus = 0;
                invalidate();
            }
        });

1.3 圆上升

这个就更简单了，改变Y轴坐标就可以了。：

  //小球上移
        mCircleMoveAnim = ValueAnimator.ofFloat(0,300);
        mCircleMoveAnim.setInterpolator(new AccelerateDecelerateInterpolator());
        mCircleMoveAnim.setDuration(500);
        mCircleMoveAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                mMoveY = (float) animation.getAnimatedValue();
                postInvalidate();
            }
        });

1.4 小球变大

上面中，我们都是用drawRoundToRect 的画的，为了方便，我们改成 drawcircle 来绘制，这个时候就可以添加一个 status，用来选择哪个；

   @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        switch (mStatus){
            case 0:
                //绘制椭圆等其他变化
                drawoval(canvas);
                break;
            case 1:
                //绘制小球变大并打钩
                drawCircle(canvas);
                break;
        }
    }

圆变大改变半径即可，有些不需要放大的，可以忽略这一步：

 //圆形变大动画
        mCircleScaleAnim = ValueAnimator.ofFloat(height/2,height*2);
        mCircleScaleAnim.setDuration(animTime);
        mCircleScaleAnim.setInterpolator(new LinearInterpolator());
        mCircleScaleAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                mCircleWidth = (float) animation.getAnimatedValue();
                mStatus = 1;
                postInvalidate();
            }
        });

1.5 打钩

前面的都比较简单，可能就打钩这里比较难，但真的难吗？当然不是，打钩我们完全可以用 pathmeasure 这个方法可以轻松搞定，就是打钩的左边需要计算；所以，首先显示打钩：

 //初始化打钩
    private void initTick(){
        mTickPaint = new Paint();
        mTickPaint.setAntiAlias(true);
        mTickPaint.setColor(Color.WHITE);
        mTickPaint.setStyle(Paint.Style.STROKE);
        mTickPaint.setStrokeWidth(10);
        int x = width/2;  //小球的中心坐标 x
        int y =  -300;   //小球的中心坐标 y
        Path path = new Path();
        //画勾
        path.moveTo(x-45,y-15);
        path.lineTo(x-15,y+20);
        path.lineTo(x+60,y-40);
        mTickPath = new Path();
        mPathMeasure = new PathMeasure(path,false); //保存打钩的路径
        mTickLength = mPathMeasure.getLength();  //获取打钩的总长度
    }

然后我们在draw中这样写：

 mTickPath.reset();
        mTickPath.rLineTo(0,0); //防止硬件加速的bug
        float start = 0;
        float end = mTickLength * mTickDrawOffsert;
        mPathMeasure.getSegment(start,end,mTickPath,true);
        canvas.drawPath(mTickPath,mTickPaint);

其中mTickPath 通过 valueanimator 来获取：

// 打钩动画
        mTickAnim = ValueAnimator.ofFloat(0,1);
        mTickAnim.setDuration(1000);
        mTickAnim.setInterpolator(new AccelerateInterpolator());
        mTickAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                mTickDrawOffsert = (float) animation.getAnimatedValue();
                mStatus = 1;
                Log.d(TAG, "onAnimationUpdate: "+mTickDrawOffsert);
                postInvalidate();
            }
        });

1.6 动画整合

上面中，我们用到很多动画，为了使它变得很流畅，那肯定得用 animatorset 啦，在点击的时候，开始我们的表演：

setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                AnimatorSet bound = new AnimatorSet();
                bound.play(mRectToRoundAnim).with(mRoundToCircleAnim);
                AnimatorSet circle = new AnimatorSet();
                circle.play(mCircleMoveAnim)
                        .before(mCircleScaleAnim)
                        .after(bound);
                AnimatorSet animatorSet = new AnimatorSet();
                animatorSet.play(mTickAnim).after(circle);
                animatorSet.start();
                setClickable(false);
            }
        });

注意观察animatorset 的 play， with，befor，after 哦

这样就完成了所有动画了，其实也没啥好讲的，就一些基础动画；下面是完成代码；

xml :

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/activity_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:clipChildren="false"
    android:clipToPadding="false"
    tools:context="com.toptech.tvhouse.MainActivity"
  >

    <com.toptech.tvhouse.view.CoolButton
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:onClick="call"
        app:text="一键加速"
        app:textsize="18sp"
        android:layout_alignParentBottom="true"
        android:layout_marginBottom="20dp"
        android:text="call phone"/>

</RelativeLayout>

文字和大小在 attrs.xml 中：

<declare-styleable name="CoolButton">
        <attr name="text" format="string"/>
        <attr name="textsize" format="dimension"/>
    </declare-styleable>

java 完成代码

/**
 * Created by zhengshaorui on 2017/5/29.
 */
public class CoolButton extends View {
    private static final String TAG = "zsr";
    private Paint mPaint;     //圆画笔
    private Paint mTextPaint;  //文字画笔
    private Paint mTickPaint; //打钩画笔
    private int width,height;
    private int mRadius;
    private float mRectToRound = 10;
    private float mRoundToCircleOffert = 0;
    private int mStatus;//根据不同类型draw不同动画
    private String mButtonText = "";
    private float mMoveY = 0;
    private float mCircleWidth;
    private Context mContext;
    private Path mTickPath = new Path();
    private ValueAnimator mRectToRoundAnim,mRoundToCircleAnim;
    private ValueAnimator mCircleScaleAnim;
    private ValueAnimator mCircleMoveAnim;
    private PathMeasure mPathMeasure;
    private float mTickLength;
    private float mTickDrawOffsert;
    private ValueAnimator mTickAnim;
    public CoolButton(Context context) {
        this(context,null);
    }
    public CoolButton(Context context, AttributeSet attrs) {
        this(context, attrs,0);
    }
    public CoolButton(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        //通过这个方法，将attrs中定义的declare-styleable 的所有属性的值存到typedarry里
        TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.CoolButton);
        int textsize = 0;
        for (int i = 0; i < ta.length(); i++) {
            int attr = ta.getIndex(i);
            switch (attr) {
                case R.styleable.CoolButton_text:
                    mButtonText = ta.getString(R.styleable.CoolButton_text);
                    textsize = ta.getDimensionPixelSize(R.styleable.CoolButton_textsize,0);
                    Log.d(TAG, "CoolButton: "+mButtonText);
                    break;
            }
        }
        ta.recycle(); //调用完记得recycle掉，避免重复调用
        mPaint = new Paint();
        mPaint.setAntiAlias(true);
        mPaint.setColor(Color.BLUE);
        mTextPaint = new Paint();
        mTextPaint.setAntiAlias(true);
        mTextPaint.setColor(Color.WHITE);
        mTextPaint.setTextSize(textsize);
        mContext = context;
        setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                AnimatorSet bound = new AnimatorSet();
                bound.play(mRectToRoundAnim).with(mRoundToCircleAnim);
                AnimatorSet circle = new AnimatorSet();
                circle.play(mCircleMoveAnim)
                        .before(mCircleScaleAnim)
                        .after(bound);
                AnimatorSet animatorSet = new AnimatorSet();
                animatorSet.play(mTickAnim).after(circle);
                animatorSet.start();
                setClickable(false);
            }
        });
    }
    private void initTick(){
        mTickPaint = new Paint();
        mTickPaint.setAntiAlias(true);
        mTickPaint.setColor(Color.WHITE);
        mTickPaint.setStyle(Paint.Style.STROKE);
        mTickPaint.setStrokeWidth(10);
        int x = width/2;
        int y =  -300;
        Path path = new Path();
        //画勾
        path.moveTo(x-45,y-15);
        path.lineTo(x-15,y+20);
        path.lineTo(x+60,y-40);
        mTickPath = new Path();
        mPathMeasure = new PathMeasure(path,false);
        mTickLength = mPathMeasure.getLength();
    }
    @Override
    public boolean isFocused() {
        return super.isFocused();
    }
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        switch (mStatus){
            case 0:
                drawoval(canvas);
                break;
            case 1:
                drawCircle(canvas);
                break;
        }
        /*int x = width/2;
        int y =  -300;
        canvas.drawCircle(x,y,height*2,mPaint);
        Path path = new Path();
        //画勾
        path.moveTo(x-50,y-15);
        path.lineTo(x-10,y+30);
        path.lineTo(x+60,y-40);
        canvas.drawPath(path,mTickPaint);*/
    }
    /**
     * 画圆角以及上升过程
     * @param canvas
     */
    private void drawoval(Canvas canvas){
        RectF rectF = new RectF(mRoundToCircleOffert,0 - mMoveY,width - mRoundToCircleOffert,height - mMoveY);
        canvas.drawRoundRect(rectF, mRectToRound, mRectToRound,mPaint);
        //绘制文字
        float textwidth = mTextPaint.measureText(mButtonText);
        float x = (width - textwidth)/2;
        Paint.FontMetrics metrics = mTextPaint.getFontMetrics();
        float textheight = (metrics.descent + metrics.ascent);
        float y =  height/2 - textheight/2;
        canvas.drawText(mButtonText,x,y,mTextPaint);
    }
    /**
     * 小圆变大并打钩
     * @param canvas
     */
    private void drawCircle(Canvas canvas){
        canvas.drawCircle((width)/2,-mMoveY,mCircleWidth,mPaint);
        mTickPath.reset();
        mTickPath.rLineTo(0,0); //防止硬件加速的bug
        float start = 0;
        float end = mTickLength * mTickDrawOffsert;
        mPathMeasure.getSegment(start,end,mTickPath,true);
        canvas.drawPath(mTickPath,mTickPaint);
    }
    private void AnimInit(){
        final int animTime = 500;
        //圆角变圆
        mRectToRoundAnim = ValueAnimator.ofFloat(10,mRadius);
        mRectToRoundAnim.setDuration(500);
        mRectToRoundAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator valueAnimator) {
                mRectToRound = (float) valueAnimator.getAnimatedValue();
                mStatus = 0;
                invalidate();
            }
        });
        //长椭圆变圆动画,并让文字渐渐消失
        mRoundToCircleAnim = ValueAnimator.ofFloat(0,(width-height)/2);
        mRoundToCircleAnim.setDuration(1000);
        mRoundToCircleAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator valueAnimator) {
                mRoundToCircleOffert = (float) valueAnimator.getAnimatedValue();
                int max = (width - height)/2 ;
                int alpha = (int) ((float)(max - mRoundToCircleOffert)/max * 255);
                mTextPaint.setAlpha(alpha);
                mStatus = 0;
                invalidate();
            }
        });
        //小球上移
        mCircleMoveAnim = ValueAnimator.ofFloat(0,300);
        mCircleMoveAnim.setInterpolator(new AccelerateDecelerateInterpolator());
        mCircleMoveAnim.setDuration(500);
        mCircleMoveAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                mMoveY = (float) animation.getAnimatedValue();
                postInvalidate();
            }
        });
        //圆形变大动画
        mCircleScaleAnim = ValueAnimator.ofFloat(height/2,height*2);
        mCircleScaleAnim.setDuration(animTime);
        mCircleScaleAnim.setInterpolator(new LinearInterpolator());
        mCircleScaleAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                mCircleWidth = (float) animation.getAnimatedValue();
                mStatus = 1;
                postInvalidate();
            }
        });
        // 打钩动画
        mTickAnim = ValueAnimator.ofFloat(0,1);
        mTickAnim.setDuration(1000);
        mTickAnim.setInterpolator(new AccelerateInterpolator());
        mTickAnim.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                mTickDrawOffsert = (float) animation.getAnimatedValue();
                mStatus = 1;
                Log.d(TAG, "onAnimationUpdate: "+mTickDrawOffsert);
                postInvalidate();
            }
        });
    }
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        width = measureWidth(widthMeasureSpec);
        height = measureHeight(heightMeasureSpec);
        mRadius = height/2;
        //需要用到   width，height 都在这初始化
        AnimInit();
        initTick();
        setMeasuredDimension(width, height);
    }
    //设置高的大小
    private int measureHeight(int heightMeasureSpec) {
        // TODO Auto-generated method stub
        int result = 0;
        //获取模式和大小
        int specMode = MeasureSpec.getMode(heightMeasureSpec);
        int specSize = MeasureSpec.getSize(heightMeasureSpec);
        if (specMode == MeasureSpec.EXACTLY) {
            result = specSize;
        } else {
            result = 70; //如果是wrap_content ,给个初始值
            if (specMode == MeasureSpec.AT_MOST) {
                result = Math.min(result, specSize);
            }
        }
        return result;
    }
    //设置宽的大小
    private int measureWidth(int widthMeasureSpec) {
        // TODO Auto-generated method stub
        int result = 0;
        //获取模式和大小
        int specMode = MeasureSpec.getMode(widthMeasureSpec);
        int specSize = MeasureSpec.getSize(widthMeasureSpec);
        if (specMode == MeasureSpec.EXACTLY) {
            result = specSize;
        } else {
            result = 70; //如果是wrap_content ,给个初始值
            if (specMode == MeasureSpec.AT_MOST) {
                result = Math.min(result, specSize);
            }
        }
        return result;
    }
}