如何给readonly属性赋值

1.

#import <UIKit/UIKit.h>

@interface myView : UIView

@property(nonatomic,readonly,assign)float width;

@property(nonatomic,readonly,assign)float height;

@end

2.

- (void)viewDidLoad {

    [super viewDidLoad];

    myView *view1=[[myView alloc]init];

    //view1.width=20;

    [view1 setValue:@20 forKey:@"width"];

    NSLog(@"view1.width＝＝%f",view1.width);

｝

输出结果：

view1.width＝＝20.000000

总结：通过kvc可以实现给readonly属性赋值。

补充的例子(设置btn位于屏幕的中心点):

UIButton *btn=[[UIButtonalloc]init];

    btn.frame=CGRectMake(0, 0, 100, 50);

    float aa=self.view.frame.size.width/2;

    float aa2=self.view.frame.size.height/2;

    CGPoint point=CGPointMake(aa, aa2);

    NSValue *val=[NSValuevalueWithCGPoint:point];

    [btn setValue:val forKey:@"center"];