将 inputAccessoryView 与多个 UITextField 和 ViewController 一起使用

Question

我正在尝试利用 inputAccessoryView 并显示帮助文本以及上一个和下一个按钮。但是，我有许多 UITextFields 跨越许多 ViewControllers。所以我想为 inputAccessoryView 提供一个可重用的 UIView。

为此，我创建了一个 xib 文件 ('SetupKeyboardAccessory') 和一个附加到该 xib 的 ViewController ('SetupKeyboardAccessoryViewController')。

SetupKeyboardAccessory：

SetupKeyboardAccessoryViewController：

@interface SetupKeyboardAccessoryViewController : UIViewController
@property (weak, nonatomic) IBOutlet UILabel *helpTextLabel;
@property (weak, nonatomic) IBOutlet UIButton *previousButton;
@property (weak, nonatomic) IBOutlet UIButton *nextButton;
@end

在我的 MainViewController 中，我有我的 UITextFields。这个 MainViewController 正在实现 UITextFieldDelegate：

MainViewController：

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField
{

    // you can create the accessory view programmatically (in code), or from the storyboard
    if (textField.inputAccessoryView == nil) {
        SetupKeyboardAccessoryViewController *accessoryView =
        [[SetupKeyboardAccessoryViewController alloc] initWithNibName:@"SetupKeyboardAccessory"
                                                bundle:nil];
        accessoryView.helpTextLabel.text = @"setting help text here";
        textField.inputAccessoryView = accessoryView.view;
    }

    //self.navigationItem.rightBarButtonItem = self.doneButton;

    return YES;
}

- (BOOL)textFieldShouldEndEditing:(UITextField *)textField {

    [textField resignFirstResponder];

    return YES;
}

当文本字段开始编辑时，我初始化我的 SetupKeyboardAccessoryViewController，设置帮助文本，然后将其设置为 inputAccessoryView。由于某种原因，帮助文本未设置。

我知道我可能在将 SetupKeyboardAccessoryViewController 的视图设置为 inputAccessoryView 时做错了。我对 iOS 开发还很陌生。所以任何帮助将不胜感激。谢谢！

Answer 1

仅仅为了实例化视图而创建视图控制器是不合适的，然后丢弃视图控制器。

如果您只有一个 SetupKeyboardAccessoryView 类，它是 UIView 的子类，您的代码会简单得多。然后在 nib 文件中创建这个类的视图，并用 :

实例化它

SetupKeyboardAccessoryView *accessoryView = [[[NSBundle mainBundle] loadNibNamed:@"SetupKeyboardAccessoryView" owner:nil options:nil] firstObject]

Answer 2

经过一番挖掘，找出了问题所在。当我试图设置helpTextLabel 的文本时，helpTextLabel 本身是零。

这是由于在视图控制器视图完全实例化之前没有设置出口。 （来源：https://stackoverflow.com/a/4005968/986105）

所以在我的 SetupKeyboardAccessoryViewController.m 文件中，我添加了自己的 init 函数：(id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil withHelpText:(NSString*)helpText

然后在 viewDidLoad 函数中，我会设置 UILabel 的文本。

SetupKeyboardAccessoryViewController.m：

@interface SetupKeyboardAccessoryViewController ()
{
    NSString* helperText;
}
@end

@implementation SetupKeyboardAccessoryViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil withHelpText:(NSString*)helpText
{
    self = [self initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }

    helperText = helpText;
    return self;
}
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    self.helpTextLabel.text = helperText;

}
- (IBAction)previousButton:(id)sender {
    NSLog(@"prev button pressed");
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

所以在我的 MainViewController 中，我只需调用我的 init 函数并删除该行来设置 UILabel 的文本。

MainViewController：

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField
{

    // you can create the accessory view programmatically (in code), or from the storyboard
    if (textField.inputAccessoryView == nil) {
        SetupKeyboardAccessoryViewController *accessoryView =
        [[SetupKeyboardAccessoryViewController alloc] initWithNibName:@"SetupKeyboardAccessory"
                                                bundle:nil withHelpText:@"setting help text here"];
        textField.inputAccessoryView = accessoryView.view;
    }

    //self.navigationItem.rightBarButtonItem = self.doneButton;

    return YES;
}

- (BOOL)textFieldShouldEndEditing:(UITextField *)textField {

    [textField resignFirstResponder];

    return YES;
}