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。