Why doesn't this UIButton show its text label?

Everything about this UIButton renders great except the text that's supposed to be on it. NSLog demonstrates that the text is in the right place. What gives?

UIButton *newTagButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[newTagButton addTarget:self action:@selector(showNewTagField) forControlEvents:UIControlEventTouchUpInside];
newTagButton.titleLabel.text = @"+ New Tag开发者_C百科";
NSLog(@"Just set button label to %@", newTagButton.titleLabel.text);
newTagButton.titleLabel.font = [UIFont systemFontOfSize:17];
newTagButton.titleLabel.textColor = [UIColor redColor];
CGSize addtextsize = [newTagButton.titleLabel.text sizeWithFont:[UIFont systemFontOfSize:17]];
CGSize buttonsize = { (addtextsize.width + 20), (addtextsize.height * 1.2) };
newTagButton.frame = CGRectMake(x, y, buttonsize.width, buttonsize.height);
[self.mainView addSubview:newTagButton];

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There are a set of APIs on UIButton that should be used to change those properties.

The titleLabel can and will be changed by the UIButton internally.

[button setTitle:title forState:state];
[button setTitleColor:color forState:state];
[button setTitleShadowColor:color forState:state];

You should always set these properties through these methods (when available) rather than touching the titleLabel directly. For fonts you can change it on the titleLabel directly since they don't provide a method on UIButton.