Ios5 textTitleAttributesForState在设置之前为空，是否进行编码？

在下面的代码中，我希望在创建

UISegmentedControl

后，

titleTextAttributesForState:

返回默认的文本属性

    simpleButton = [[UISegmentedControl alloc] initWithItems:[NSArray arrayWithObject:@"My Button"]];
    simpleButton.segmentedControlStyle = UISegmentedControlStyleBar;
    simpleButton.momentary = YES;
    simpleButton.tintColor = [UIColor blueColor];
    NSLog(@"%@ - %@ - titleTextAttributesForState: %@", INTERFACENAME, NSStringFromSelector(_cmd) , [simpleButton titleTextAttributesForState:UIControlStateNormal]);

    [simpleButton setTitleTextAttributes:
     [NSDictionary dictionaryWithObjectsAndKeys:
      [UIFont boldSystemFontOfSize:12.0f], UITextAttributeFont, 

      nil] 
                                forState:UIControlStateNormal]; 

    NSLog(@"%@ - %@ - titleTextAttributesForState: %@", INTERFACENAME, NSStringFromSelector(_cmd) , [simpleButton titleTextAttributesForState:UIControlStateNormal]);

尽管从NSLog输出中可以看到，它不是

2011-11-03 17:28:45.492 io[80933:11903] IoUISESimpleButton - createElement - titleTextAttributesForState: (null)
2011-11-03 17:28:49.368 io[80933:11903] IoUISESimpleButton - createElement -     titleTextAttributesForState: {
Font = "<UICFFont: 0x99c2040> font-family: \"Helvetica\"; font-weight: bold; font-style: normal; font-size: 12px";}

然后在我的

-（id）initWithCoder:（NSCoder*）解码器中

    [encoder encodeObject:simpleButton     forKey:@"simpleButton" ];

    simpleButton = [decoder decodeObjectForKey:@"simpleButton"];

它不会保存我设置的

setTitleTextAttributes:forState:

。（更改字体、大小和颜色）

我最后不得不补充：

[encoder encodeObject:[simpleButton titleTextAttributesForState:UIControlStateNormal]     forKey:@"simpleButtonTitleTextAttributes" ];

及

用于保存文本属性

谢谢

    [simpleButton setTitleTextAttributes:[decoder decodeObjectForKey:@"simpleButtonTitleTextAttributes"] forState:UIControlStateNormal];