跟随手指的小球【自定义View】

需求：
1.小球可以随着手指移动而移动，在移动完成后，不会调用该控件的点击事件。
2.点击控件不移动的话，就是点击事件，小球不会移动。

效果图.gif

      自定义View绘制一个小球

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        paint.setColor(0xFFFF00FF);
        canvas.drawCircle(currentX, currentY, radius, paint);
    }

      跟随手指的小球

 @Override
 public boolean onTouchEvent(MotionEvent event) {
    currentX = event.getX();
    currentY = event.getY();
    invalidate();
    return super.onTouchEvent(event);
}

       我们随便点个位置，发现小球会直接在点的位置进行绘制，而不是跟着手指进行移动，于是，进行优化

 @Override
    public boolean onTouchEvent(MotionEvent event) {

        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                startX = event.getX();
                startY = event.getY();
                break;
            case MotionEvent.ACTION_MOVE:
                float endX = event.getX();
                float endY = event.getY();
                if (Math.abs(startX - endX) > 8 || Math.abs(startY - endY) > 8) {
                    currentX = endX;
                    currentY = endY;
                    invalidate();
                }
                break;
            case MotionEvent.ACTION_UP:
                    break;
        }
        return super.onTouchEvent(event);
    }

      小球随手指进行移动，小球可能超出了屏幕，因此进行判断：小球不能被手机屏幕的上，下，左，右遮盖

 if ((Math.abs(startX - endX) > 8 || Math.abs(startY - endY) > 8)
          && (getWidth() > (endX + radius) && endX > radius)
          && (getHeight() > (endY + radius) && endY > radius)) {
     currentX = endX;
     currentY = endY;
     invalidate();
}

      我想要给该控件添加点击事件，结果发现无论是点击和滑动该控件，都会调用该控件的点击事件，我想要只有点击的时候会调用控件的点击事件，而小球随手指滑动的是否不会调用点击事件，进一步优化的结果

package hf.text.customizeview.drawable_bool;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

public class BallMovesWithFinger extends View {

    private Paint paint;
    private float currentX = 60;
    private float currentY = 60;
    private float radius = 60;


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

    public BallMovesWithFinger(Context context, @Nullable AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public BallMovesWithFinger(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        paint = new Paint();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        paint.setColor(0xFFFF00FF);
        canvas.drawCircle(currentX, currentY, radius, paint);
    }

    float startX = 0f;
    float startY = 0f;
    boolean flag = false;


    @Override
    public boolean onTouchEvent(MotionEvent event) {

        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                startX = event.getX();
                startY = event.getY();
                flag = false;
                break;
            case MotionEvent.ACTION_MOVE:
                float endX = event.getX();
                float endY = event.getY();
                if ((Math.abs(startX - endX) > 8 || Math.abs(startY - endY) > 8)
                        && (getWidth() > (endX + radius) && endX > radius)
                        && (getHeight() > (endY + radius) && endY > radius)) {
                    currentX = endX;
                    currentY = endY;
                    invalidate();
                    flag = true;
                    return true;
                }
                break;
            case MotionEvent.ACTION_UP:
                if (flag) {
                    return true;
                } else {
                    break;
                }
        }
        return super.onTouchEvent(event);
    }

}