自定义UITextField

目的是实现如下的效果：

UITextField的leftView是自定义的UIView，其中：

1、包含一个居中显示的icon，并且上，左，下各有1px的间隙

2、左上和左下是圆角，右边没有圆角

居中展示icon

关键是leftView不是UIImageView，而是把UIImageView设置为subview

CGFloat height = frame.size.height;        UIView *leftView = [[UIView alloc] initWithFrame:CGRectMake(0, 1, height - 1, height - 2)];        UIImageView *icon = [[UIImageView alloc] initWithImage:[UIImage imageNamed:iconName]];icon.frame = CGRectMake(height / 4, height / 4, height / 2, height / 2);[leftView addSubview:icon];

上面的代码，使icon在leftView居中显示

制造1px间隙

top和bottom的间隙很容易做，只要令leftView的height比UITextField的height少2，然后y设置为1

左侧的间隙比较麻烦，首先将width设置为比UITextField的width少1。但是直接设置x为1无效，需要override以下方法：

-(CGRect) leftViewRectForBounds:(CGRect)bounds {    CGRect iconRect = [super leftViewRectForBounds:bounds];    iconRect.origin.x += 1;    return iconRect;}

制造部分圆角

制造所有的圆角比较简单，只需要：

self.layer.cornerRadius = 5;

但是要制造部分圆角，就比较麻烦：

UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:leftView.bounds byRoundingCorners:UIRectCornerTopLeft | UIRectCornerBottomLeft cornerRadii:CGSizeMake(5, 5)];CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];maskLayer.frame = leftView.bounds;maskLayer.path = maskPath.CGPath;leftView.layer.mask = maskLayer;

创建阴影

self.layer.shadowColor = [UIColor colorWithRed:132/255.0f green:214/255.0f blue:219/255.0f alpha:1.0f].CGColor;self.layer.shadowOpacity = 0.5;self.layer.shadowOffset = CGSizeMake(3, 3);

完整的代码

@implementation LosTextField-(id)initWithFrame:(CGRect)frame Icon:(NSString*)iconName{    self = [super initWithFrame:frame];    if (self) {    CGFloat height = frame.size.height;    UIView *leftView = [[UIView alloc] initWithFrame:CGRectMake(0, 1, height - 1, height - 2)];  leftView.backgroundColor = [UIColor colorWithRed:132/255.0f green:214/255.0f blue:219/255.0f alpha:1.0f];    UIImageView *icon = [[UIImageView alloc] initWithImage:[UIImage imageNamed:iconName]];  icon.frame = CGRectMake(height / 4, height / 4, height / 2, height / 2);  [leftView addSubview:icon];    UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:leftView.bounds byRoundingCorners:UIRectCornerTopLeft | UIRectCornerBottomLeft cornerRadii:CGSizeMake(5, 5)];  CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];  maskLayer.frame = leftView.bounds;  maskLayer.path = maskPath.CGPath;  leftView.layer.mask = maskLayer;    self.leftView = leftView;  self.leftViewMode = UITextFieldViewModeAlways;    }    return self;}-(CGRect) leftViewRectForBounds:(CGRect)bounds {    CGRect iconRect = [super leftViewRectForBounds:bounds];    iconRect.origin.x += 1;    return iconRect;}@end

self.username = [[LosTextField alloc] initWithFrame:CGRectMake(20, 150, 280, 40) Icon:@"login_username"];