ios7 uinavigationcontroller

- (void)viewDidLoad{
    [super viewDidLoad];
    
    
    UIImageView *imageView =[[UIImageView alloc]initWithFrame:CGRectMake(0.0f, 0.0f, 100.0f, 40.0f)];
    //通过保持长宽比的大小选择规模内容视图，任何剩余的视图区域的边界是透明的。
    imageView.contentMode = UIViewContentModeScaleAspectFit;
    
    /*读取一个图片. Be careful, this image will be cached */
    UIImage *image = [UIImage imageNamed:@"Logo"];
    
    //设置imageView的图片为image
    [imageView setImage:image];
    
    //设置titleView
    self.navigationItem.titleView = imageView;
    
}