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如何在导航栏上设置backbuttonem的操作?

back-button uinavigationbar uinavigationcontroller iphone

yozhik · 技术社区 · 15 年前

如何在导航栏上设置backbuttonem的操作?我有一个导航栏,当我按下后退按钮时,我需要提醒用户一些信息,只有在用户做出反应后-返回到上一个视图。我该怎么做?谢谢!

- (void)viewDidLoad 
{
    [super viewDidLoad];

    //no one field don't changed yet
    isDirty = FALSE;

    //edited user
    //set default values
    newData = [data copy];

    //setting navigation controller rigth button
    UIBarButtonItem *rightButton = [[UIBarButtonItem alloc] initWithTitle:@"Save"
                                                                style:UIBarButtonSystemItemDone 
                                                                   target: self 
                                                                   action: @selector(saveBtnUserClick)];
    self.navigationItem.rightBarButtonItem = rightButton; 
    [rightButton release];


    UIBarButtonItem *leftButton = [[UIBarButtonItem alloc] initWithTitle:@"Back"
                                                                   style:UIBarButtonSystemItemDone 
                                                                  target: self 
                                                                  action: @selector(backBtnUserClick)];

    self.navigationItem.backBarButtonItem = leftButton;
    [leftButton release];
}

//我的反应方法

-(IBAction) backBtnUserClick
{
    NSLog(@"\n Back pressed");

    //back to previous view
    [self.navigationController popViewControllerAnimated: TRUE];
}

2 回复 | 直到 15 年前

Sajjad Ali Tom Harrington 11 年前

这听起来像是一份工作 UIAlertView . 而不是调用popViewControllerImated: IBAction 方法,alloc/init a UIAlertView 把它呈现出来。然后,当用户点击 UIAlertView ,取消 UIAlertView 打电话来 popViewControllerAnimated: .

- (IBAction)backBtnUserClicked:(id)object {
    UIAlertView *av = [[[UIAlertView alloc] initWithMessage:@"Wait!"
          delegate:self
               cancelButtonTitle:@"Ok"
               otherButtonTitles:nil] autorelease];
   [av show];
}

在你的 UIAlertViewDelegate 方法调用 PopViewControllerImated: .

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex {
    [[self navigationController] popViewControllerAnimated:YES];
}

要设置“后退”按钮上的操作:

[[[self navigationController] leftBarButtonItem] setTarget:self];
[[[self navigationController] leftBarButtonItem] setAction:@selector(backBtnUserClicked:)];

Christian Loncle 14 年前

在头文件中添加<UINavigationControllerDelegate>,并在.m中使用它

- (BOOL)navigationBar:(UINavigationBar *)navigationBar shouldPopItem:(UINavigationItem     *)item
{
  //insert your back button handling logic here
  // let the pop happen
  return YES;
}