Android自定view画圆效果

这是一个自定义view画圆，对于初学自定义view的小伙伴这是一个很好的帮助。

看图

代码：

package sjx.com.custonview;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.Window;

/**
* dell 孙劲雄
* 2017/9/1
* 19:57
*/

public class Custonm extends View {
 private float currentX = 40;
 private float currentY = 50;
 public Custonm(Context context) {
   super(context);
 }

public Custonm(Context context, AttributeSet attrs) {
   super(context, attrs);
 }

public Custonm(Context context, AttributeSet attrs, int defStyleAttr) {
   super(context, attrs, defStyleAttr);
 }
//测量
 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
   super.onMeasure(widthMeasureSpec, heightMeasureSpec);
 }
//摆放
 @Override
 protected void onLayout(boolean changed, int left, int top, int right, int bottom) {

super.onLayout(changed, left, top, right, bottom);

}

@Override
 protected void onDraw(Canvas canvas) {
   super.onDraw(canvas);

Paint paint=new Paint();

paint.setColor(Color.RED);

paint.setStyle(Paint.Style.FILL);

paint.setAntiAlias(true);

canvas.drawCircle(currentX,currentY,30,paint);

}

@Override
 public boolean dispatchTouchEvent(MotionEvent event) {
   return super.dispatchTouchEvent(event);
 }

@Override
 public boolean onTouchEvent(MotionEvent event) {

currentX=event.getX();
   currentY=event.getY();

invalidate();

switch (event.getAction()){

case MotionEvent.ACTION_DOWN:
       Log.i("sss", "按下");
       break;
     case MotionEvent.ACTION_MOVE:
       Log.i("sss", "移动");

break;
     case MotionEvent.ACTION_UP:
       Log.i("sss", "弹起");
       break;
   }
   return true;

}
}

来源：http://blog.csdn.net/sunzhi_/article/details/78336998