奇数项UIBarButtonItem在UIToolbar 中的居中对齐

toolBar = [[UIToolbar alloc] initWithFrame:CGRectMake(0, 0, 320, 44)];toolBar.barStyle = UIBarStyleDefault; UIBarButtonItem *titleButton = [[UIBarButtonItem alloc] initWithTitle:title                                                                         style: UIBarButtonItemStylePlain                                                                        target: nil                                                                        action: nil];        UIBarButtonItem *rightButton = [[UIBarButtonItem alloc] initWithTitle:@"完成"                                                                         style: UIBarButtonItemStyleDone                                                                        target: self                                                                        action: @selector(done)];        //UIBarButtonItem *leftButton  = [[UIBarButtonItem alloc] initWithTitle:@"取消" //                                                                        style: UIBarButtonItemStyleBordered //                                                                       target: self //                                                                       action: @selector(docancel)];        UIBarButtonItem *fixedButton  = [[UIBarButtonItem alloc] initWithBarButtonSystemItem: UIBarButtonSystemItemFlexibleSpace                                                                                       target: nil                                                                                       action: nil];        NSArray *array = [[NSArray alloc] initWithObjects:fixedButton,fixedButton, titleButton,fixedButton, rightButton, nil];[toolBar setItems: array];[titleButton release];//[leftButton  release];[rightButton release];[fixedButton release];[array       release];

 

对齐通过填充FlexibleSpace来实现。