navigationItem的leftBarButtonItem和rightBarButtonItem隐藏

- (void)showEdit {

    if (不符合显示条件) {

 

        self.navigationItem.rightBarButtonItem.customView.hidden = YES;
　　　//[self.navigationItem.rightBarButtonItem.customView setAlpha:0.0];

   } else{

 

        self.navigationItem.rightBarButtonItem.customView.hidden = NO;
　　　//[self.navigationItem.rightBarButtonItem.customView setAlpha:1.0];

    }

}

 

经过亲自尝试,该种方法并不能实现隐藏和显示功能,于是,尝试用下面这种方法成功解决了问题

- (void)showEdit {

    if (符合显示条件) {

        if (self.navigationItem.rightBarButtonItem == nil) {

 

            self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"编辑" style:UIBarButtonItemStyleDone target:self action:@selector(edit:)];

        }

    } else{

        if (self.navigationItem.rightBarButtonItem) {

 

            self.navigationItem.rightBarButtonItem = nil;

        }

    }

}