import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.graphics.RectF;

import android.util.AttributeSet;

import android.view.MotionEvent;

import android.view.View;



/**

 * Created by Administrator on 2017/4/17.

 */

public class MyView extends View{

    private static final String TAG = "TJView";

    private int padding = 8;

    //画笔工具

    private Paint mPaint;

    //圆心坐标

    private float currentX = 0;

    private float currentY = 0;

    //大圆半径

    private float radiusBig = 200;

    //中圆半径

    private float radiusCenter = radiusBig / 2;

    //小圆半径

    private float radiusSmall = radiusCenter / 3;

    private int width;

    private int height;

    private float distance;

    private final float increment = 10;

    private final float min = 50;

    public MyView(Context context) {

        this(context, null);

    }



    public MyView(Context context, AttributeSet attrs) {

        this(context, attrs, 0);

    }



    public MyView(Context context, AttributeSet attrs, int defStyleAttr) {

        super(context, attrs, defStyleAttr);

        mPaint = new Paint();

        mPaint.setAntiAlias(true);

       // setAnimation();

    }



    /**

     * 设置缩放动画

     */

    /*private void setAnimation() {

        ScaleAnimation scaleAnimation2 = new ScaleAnimation(0.7f, 1.0f, 0.7f, 1.0f, ScaleAnimation.RELATIVE_TO_PARENT, 0.5f, ScaleAnimation.RELATIVE_TO_PARENT, 0.5f);

        scaleAnimation2.setDuration(500);// 设置持续时间

        scaleAnimation2.setRepeatCount(99999);// 设置重复次数

        scaleAnimation2.setFillAfter(true);// 保持动画结束时的状态

        startAnimation(scaleAnimation2);

    }*/



    @Override

    protected void onDraw(Canvas canvas) {

        super.onDraw(canvas);

        drawBg(canvas);

        drawLeftHalfCirle(canvas);

        drawTBCirle(canvas);

    }



    /**

     * 画上下两个圆--中圆和小圆

     *

     * @param canvas

     */

    private void drawTBCirle(Canvas canvas) {

        //画上面的白中圆

        mPaint.setColor(Color.WHITE);

        canvas.drawCircle(currentX, currentY - radiusBig / 2, radiusCenter, mPaint);

        //画上面的黑小圆

        mPaint.setColor(Color.BLACK);

        canvas.drawCircle(currentX, currentY - radiusBig / 2, radiusSmall, mPaint);

        //画下面的黑中圆

        mPaint.setColor(Color.BLACK);

        canvas.drawCircle(currentX, currentY + radiusBig / 2, radiusCenter, mPaint);

        //画下面的白小圆

        mPaint.setColor(Color.WHITE);

        canvas.drawCircle(currentX, currentY + radiusBig / 2, radiusSmall, mPaint);

    }



    /**

     * 画左边半圆

     *

     * @param canvas

     */

    private void drawLeftHalfCirle(Canvas canvas) {

        mPaint.setColor(Color.WHITE);

        canvas.drawArc(new RectF(currentX - radiusBig, currentY - radiusBig, currentX + radiusBig, currentY + radiusBig), 90, 180, true, mPaint);//90度开始画180度

    }



    /**

     * 画黑色的背景底板

     *

     * @param canvas

     */

    private void drawBg(Canvas canvas) {

        mPaint.setColor(Color.BLACK);

        canvas.drawCircle(currentX, currentY, radiusBig + padding, mPaint);

    }



    @Override

    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        currentX = MeasureSpec.getSize(widthMeasureSpec) / 2;

        currentY = MeasureSpec.getSize(heightMeasureSpec) / 2;

        setMeasuredDimension(widthMeasureSpec, heightMeasureSpec);

        width = getWidth();

        height = getHeight();

    }



    @Override

    public boolean onTouchEvent(MotionEvent event) {

        /*currentX = event.getX();

        currentY = event.getY();

        invalidate();

        return true;*/

        //手指的数量

        int count = event.getPointerCount();

        float x = event.getX();

        float y = event.getY();

        int action = event.getAction();

        if(action==MotionEvent.ACTION_POINTER_DOWN){

            distance = getDistance(event);

        }

        if(count==1) {

            if (action == MotionEvent.ACTION_UP || action == MotionEvent.ACTION_MOVE) {

                if (x > width - radiusBig) {

                    x = width - radiusBig;

                } else if (x < radiusBig) {

                    currentX = radiusBig;

                } else {

                    currentX = x;

                }

                if (y > height - radiusBig) {

                    currentY = height - radiusBig;

                } else if (y < radiusBig) {

                    currentY = radiusBig;

                } else {

                    currentY = y;

                }

                postInvalidate();

            }

        }

        else if(count==2&&action == MotionEvent.ACTION_MOVE){



            float maxR = 0;



            if(currentX
                maxR = currentX;

            }else{

                maxR = currentY;

            }



            //判断手指方向

            if(distance>getDistance(event)){

                radiusBig -= increment;

                if(radiusBig
                    radiusBig = min;

                }

            }else if(distance
                radiusBig += increment;

                if(radiusBig>maxR){

                    radiusBig = maxR;

                }else if(radiusBig>width/2){

                    radiusBig = width/2;

                }

            }

            distance = getDistance(event);

            postInvalidate();

        }

        return true;

    }

    private float getDistance(MotionEvent event){



        float xOne = event.getX(0);

        float yOne = event.getY(0);

        float xTwo = event.getX(1);

        float yTwo = event.getY(1);

        return (xOne - xTwo)*(xOne - xTwo)+(yOne - yTwo)*(yOne - yTwo);

    }

}