我们如何在单击UIBarButton“add”时创建textField

Question

- (void)viewDidLoad {
    [super viewDidLoad];
self.navigationItem.rightBarButtonItem = [[[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(add:)] autorelease];
}

-(IBAction) add :(id)sender {

}

在视图文本字段中找不到的诀窍是当我单击添加textfiled时出现在视图中

Answer 1

您可以提前创建文本字段并将其添加到视图中并将隐藏属性设置为YES，此外，您只需将hidden设置为NO即可使其显示。

- (void)loadView
{
    UIView * newView = [[UIView alloc] init];

    // retaining property
    self.myTextField = [[[UITextField alloc] init] autorelease];
    myTextField.hidden = YES;

    [newView addSubview:myTextField];

    self.view = newView;
    [newView release];
}

- (IBAction)add:(id)sender 
{
    myTextField.hidden = NO;
}

每次调用add时都添加一个新的UITextField

- (IBAction)add:(id)sender 
{
    UITextField * textfieldToAdd = [[[UITextField alloc] init] autorelease];
    // ... configuration code for textfield ...
    [self.view addSubview:textfieldToAdd];
}