Android中自定义圆形选择器（可用于数字选择，评价选择等）

下面是自定义view代码，可以根据实际需求更改最大值，直接在xml中引用然后直接调用接口就可以获取滑动的数值

public class Custom_SelectNnm_Circle extends View {

    private static final double RADIAN = 180 / Math.PI;
    private Context context;
    private Paint circle_Paint; //圆环的画笔
    private Paint select_Paint; //选中区域的画笔
    private Paint dot1;   //圆点1
    private int max_progress; //设置最大值
    public static  int cur_progress; //设置当前值
    private int bottom_color;//设置底色
    private int circle_color; //设置滑过的颜色
    private int circle_color2; //设置圆的颜色（锚点）
    private int cricle_width; //圆环的宽度
    private double cur_Angle;  //当前锚点1旋转角度
    private float mWheelCurX, mWheelCurY; //圆的位置
    private float ring_Radius;//圆环的半径
    private  OnSeekBarChangeListener changeListener; //设置监听

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

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

    public Custom_SelectNnm_Circle(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        this.context=context;
        initAttrs(attrs,defStyleAttr);
        initPadding();
        initPaint();
    }

    private void initPaint(){

          /*
        圆环的画笔
         */
        circle_Paint=new Paint(Paint.ANTI_ALIAS_FLAG);
        circle_Paint.setAntiAlias(true);
        circle_Paint.setColor(bottom_color);
        circle_Paint.setStyle(Paint.Style.STROKE);
        circle_Paint.setStrokeWidth(cricle_width);

        /*
        选中区域的画笔
         */
        select_Paint=new Paint(Paint.ANTI_ALIAS_FLAG);
        //select_Paint.setShader(new SweepGradient(0, 0, arrColorCircle, null));
        select_Paint.setColor(circle_color);
        select_Paint.setAntiAlias(true);
        select_Paint.setStyle(Paint.Style.STROKE);
        select_Paint.setStrokeWidth(cricle_width);

        //画圆点
        dot1 = new Paint(Paint.ANTI_ALIAS_FLAG);
        dot1.setColor(circle_color2);
        circle_Paint.setAntiAlias(true);
        dot1.setStyle(Paint.Style.FILL);
    }


    private void initAttrs(AttributeSet attrs,int def){
        TypedArray typedArray = getContext().obtainStyledAttributes(attrs, R.styleable.circle_parameter, def, 0);
        max_progress=typedArray.getInt(R.styleable.circle_parameter_max_progress,20);
        cur_progress=typedArray.getInt(R.styleable.circle_parameter_cur_progress,5);
        if (cur_progress > max_progress) cur_progress = max_progress;
        bottom_color=typedArray.getColor(R.styleable.circle_parameter_bottom_color,getColor(R.color.custom_circle));
        circle_color=typedArray.getColor(R.styleable.circle_parameter_circle_color,getColor(R.color.custom_circle2));
        circle_color2=typedArray.getColor(R.styleable.circle_parameter_circle_color2,getColor(R.color.custom_circle3));
        Bitmap evaluatebg = BitmapFactory.decodeResource(context.getResources(), R.mipmap.select_evaluate_bg);
        Bitmap center = BitmapFactory.decodeResource(context.getResources(), R.mipmap.select_evaluate_center);
        int width = evaluatebg.getWidth();
        int width1 = center.getWidth();
        cricle_width=(width-width1)/4;
        typedArray.recycle();
    }

    //测量布局大小，规定xy点的坐标
    @Override
    public  void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        Bitmap bitmap = BitmapFactory.decodeResource(context.getResources(), R.mipmap.select_evaluate_center);
        int height = bitmap.getHeight()+cricle_width*2;   //
        int width = bitmap.getWidth()+cricle_width*2;
        int min = Math.min(height, width);
        setMeasuredDimension(min,min);
        initposition();
    }

    //初始化边距
    private void initPadding(){
        int paddingLeft = getPaddingLeft();
        int paddingTop = getPaddingTop();
        int paddingRight = getPaddingRight();
        int paddingBottom = getPaddingBottom();
        int paddingStart = 0, paddingEnd = 0;
        if (Build.VERSION.SDK_INT >= 17) {
            paddingStart = getPaddingStart();
            paddingEnd = getPaddingEnd();
        }
        int maxPadding = Math.max(paddingLeft, Math.max(paddingTop,
                Math.max(paddingRight, Math.max(paddingBottom, Math.max(paddingStart, paddingEnd)))));
        setPadding(maxPadding, maxPadding, maxPadding, maxPadding);
    }


    private void initposition(){
        //转换为360度
        cur_Angle=(double) cur_progress / max_progress*360.0;
        //计算初始化旋转的角度
        double cos = -Math.cos(Math.toRadians(cur_Angle));
        //根据旋转的角度来确定位置
        MakeCurPosition(cos);
        //确定圆环的半径
        ring_Radius=(getMeasuredWidth() - getPaddingLeft() - getPaddingRight() - cricle_width) / 2;
    }


    private void MakeCurPosition(double cos){
        //根据旋转的角度来确定圆的位置
        //确定x点的坐标
        mWheelCurX = calcXLocationInWheel(cur_Angle, cos);
        //确定y点的坐标
        mWheelCurY=calcYLocationInWheel(cos);
    }


    //确定x点的坐标
    private float calcXLocationInWheel(double angle,double cos){
        if (angle < 180) {
            return (float) (getMeasuredWidth() / 2 + Math.sqrt(1 - cos * cos) * ring_Radius); //Math.sqrt正平分根  9-3
        } else {
            return (float) (getMeasuredWidth() / 2 - Math.sqrt(1 - cos * cos) * ring_Radius);
        }
    }

    //确定y点的坐标
    private float calcYLocationInWheel(double cos) {
        return getMeasuredWidth() / 2 + ring_Radius * (float) cos;
    }
    //获取颜色
    @TargetApi(Build.VERSION_CODES.M)
    private int getColor(int colorId) {
        final int version = Build.VERSION.SDK_INT;
        if (version >= 23) {
            return getContext().getColor(colorId);
        } else {
            return ContextCompat.getColor(getContext(), colorId);
        }
    }

    //画

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        float left = getPaddingLeft() + cricle_width / 2;
        float top = getPaddingTop() + cricle_width / 2;
        float right = canvas.getWidth() - getPaddingRight() - cricle_width / 2;
        float bottom = canvas.getHeight() - getPaddingBottom() - cricle_width / 2;
        float centerX = (left + right) / 2;
        float centerY = (top + bottom) / 2;

        float wheelRadius = (canvas.getWidth() - getPaddingLeft() - getPaddingRight()) / 2 - cricle_width / 2;
        //画圆
        canvas.drawCircle(centerX, centerY, wheelRadius, circle_Paint);

        //画圆弧
        float stop=0;
        stop=(float) Math.abs(cur_Angle);
        canvas.drawArc(new RectF(left, top, right, bottom), -90,stop, false, select_Paint);

        //画圆点
        canvas.drawCircle(mWheelCurX, mWheelCurY, cricle_width/2, dot1);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        float x = event.getX();
        float y = event.getY();
        if(event.getAction()==MotionEvent.ACTION_MOVE || isMovedot1(x,y) ==true  ){
            Log.i("TAG","进入X="+x+"进入Y="+y);
            //通过触摸点算出cos角度值
            float cos = calculateCos(x, y);
            // 通过反三角函数获得角度值
            double angle;   //获取滑动的角度
            if (x < getWidth() / 2) { // 滑动超过180度
                angle = Math.PI * RADIAN + Math.acos(cos) * RADIAN;    //通过计算得到滑动的角度值
            } else { // 没有超过180度
                angle = Math.PI * RADIAN - Math.acos(cos) * RADIAN; //PI 周长比直径    返回弧角度的余弦值
            }
                cur_Angle=angle;
                cur_progress=getSelectedValue(cur_Angle);
                Log.i("tag",cur_progress+"+++++++++++++++++++");
                MakeCurPosition(cos);
            if (changeListener != null) {
                Log.i("guo","改了+++改改2222222");
                changeListener.onChanged(this, cur_progress);
            }
            invalidate();
            return true;
        }else {
            return super.onTouchEvent(event);
        }
    }

    //
    private  boolean isMovedot1(float x,float y){
        float dot1x = Math.abs(mWheelCurX - x);
        float dot1y = Math.abs(mWheelCurY - y);
        if(dot1x<50 && dot1y<50){
            return true;
        }else{
            return false;
        }
    }

    //拿到切斜角的cos值
    private float calculateCos(float x, float y){
        float width = x - getWidth() / 2;
        float height = y - getHeight() / 2;
        float slope = (float) Math.sqrt(width * width + height * height);
        return height / slope;
    }

    private int getSelectedValue(double mCurAngle) {
        return Math.round(max_progress * ((float) mCurAngle / 360));  //四舍五入
    }

    public void setOnSeekBarChangeListener(OnSeekBarChangeListener listener) {
        changeListener = listener;
    }

    public interface OnSeekBarChangeListener {
        void onChanged(Custom_SelectNnm_Circle seekbar, int curValue);
    }
}

效果图

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