设置Button的圆角效果
UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:button.bounds cornerRadius:10.0];
CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
maskLayer.frame = button.bounds;
maskLayer.path = maskPath.CGPath;
button.layer.mask = maskLayer;
UIBezierPath *maskPath2 = [UIBezierPath bezierPathWithRoundedRect:button2.bounds byRoundingCorners:UIRectCornerTopLeft | UIRectCornerBottomLeft cornerRadii:CGSizeMake(10, 10)];
CAShapeLayer *maskLayer2 = [[CAShapeLayer alloc] init];
maskLayer2.frame = button.bounds;
maskLayer2.path = maskPath2.CGPath;
button2.layer.mask = maskLayer2;