Objective-C(Swift) IBDesignable/IBInspectable

iOS8新特性IBDesignable/IBInspectable，利用运行时机制，可以把属性映射到XIB上了，同时我们UI类的自定义属性也可以映射上去，可以直接在XIB或者Storyboard中设置UI类的属性。

Objective-C实例：
.h中代码如下

@interface ZWView : UIView

@property (nonatomic, assign)IBInspectable CGFloat cornerRadius;
@property (nonatomic, assign)IBInspectable CGFloat bwidth;
@property (nonatomic, assign)IBInspectable UIColor *bcolor;

@end

.m中代码：

#import "ZWView.h"
IB_DESIGNABLE

@implementation ZWView

- (void)setCornerRadius:(CGFloat)cornerRadius{
    _cornerRadius = cornerRadius;
    self.layer.cornerRadius  = _cornerRadius;
    self.layer.masksToBounds = YES;
}

- (void)setBcolor:(UIColor *)bcolor{
    _bcolor = bcolor;
    self.layer.borderColor = _bcolor.CGColor;
}

- (void)setBwidth:(CGFloat)bwidth {
    _bwidth = bwidth;
    self.layer.borderWidth = _bwidth;
}

-(void)drawRect:(CGRect)rect{

    NSString *drawString = @"www.baidu.com";
    [drawString drawInRect:CGRectMake(20, 20, 180, 30) withFont:[UIFont systemFontOfSize:12.0]];

}

@end

在xib中拖入一个View，设置class为ZWView，设置完后便可以在xib中看到三个属性值

设置三个属性值后，效果如下：

Swift实例:

同样创建一个ZWView，代码如下：

import UIKit

@IBDesignable class zwView: UIView {

    @IBInspectable var cornerRadius:CGFloat = 0.0 {
        didSet{
           layer.cornerRadius = cornerRadius
           layer.masksToBounds = true
        }
    }

    @IBInspectable var borderColor:UIColor = UIColor(){
        didSet{
          layer.borderColor = borderColor.CGColor
        }
    }

    @IBInspectable var borderWith :CGFloat = 0.0{
        didSet{
           layer.borderWidth = borderWith
        }
    }
}

在xib中拖入View,设置class和属性值

效果如下：