下划线样式的textField

继承textField重写drawRect

- (void)drawRect:(CGRect)rect {

CGContextRefcontext =UIGraphicsGetCurrentContext();

//设置下划线的颜色

CGContextSetFillColorWithColor(context, [UIColorredColor].CGColor);

//设置textField的frame

CGContextFillRect(context,CGRectMake(0,CGRectGetHeight(self.frame) -0.5,CGRectGetWidth(self.frame),0.5));

}