Android自定view画圆效果

 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; } }