IOS 自定义标题文字

self.navigationItem.leftBarButtonItem=[[[UIBarButtonItem
alloc] initWithTitle:@"返回"
style:UIBarButtonItemStylePlain
target:self
action:@selector(pushAction)]
autorelease];

UILabel *customLab = [[UILabel
alloc] initWithFrame:CGRectMake(0,
0, self.view.frame.origin.x/2,
30)];

[customLab setTextColor:[UIColor
whiteColor]];
[customLab
setText:@"标题"];
customLab.font = [UIFont
boldSystemFontOfSize:30];

self.navigationItem.titleView = customLab;