ios - 带有 "Previous"和 "Next"的工具栏用于键盘 inputAccessoryView

Question

我一直在尝试实现此工具栏，其中当顶部文本字段是第一个响应者时仅启用“下一步”按钮，而当底部文本字段是第一个响应者时仅启用“上一个”按钮。

它有点管用，但不断发生的是我需要每次点击“上一个”/“下一个”按钮两次以启用/禁用相反的按钮。

我是否在响应链中遗漏了导致这种情况发生的某些东西？

这是我的代码:

- (void)viewDidLoad
{
    [super viewDidLoad];
    [self.topText becomeFirstResponder];
}


- (UIToolbar *)keyboardToolBar {

    UIToolbar *toolbar = [[UIToolbar alloc] init];
    [toolbar setBarStyle:UIBarStyleBlackTranslucent];
    [toolbar sizeToFit];

    UISegmentedControl *segControl = [[UISegmentedControl alloc] initWithItems:@[@"Previous", @"Next"]];
    [segControl setSegmentedControlStyle:UISegmentedControlStyleBar];
    segControl.momentary = YES;
    segControl.highlighted = YES;

    [segControl addTarget:self action:@selector(changeRow:) forControlEvents:(UIControlEventValueChanged)];
    [segControl setEnabled:NO forSegmentAtIndex:0];

    UIBarButtonItem *nextButton = [[UIBarButtonItem alloc] initWithCustomView:segControl];

    NSArray *itemsArray = @[nextButton];

    [toolbar setItems:itemsArray];

    return toolbar;
}

- (void)changeRow:(id)sender {

    int idx = [sender selectedSegmentIndex];

    if (idx == 1) {
        [sender setEnabled:NO forSegmentAtIndex:1];
        [sender setEnabled:YES forSegmentAtIndex:0];
        self.topText.text = @"Top one";
        [self.bottomText becomeFirstResponder];
    }
    else {
        [sender setEnabled:NO forSegmentAtIndex:0];
        [sender setEnabled:YES forSegmentAtIndex:1];
        self.bottomText.text =@"Bottom one";
        [self.topText becomeFirstResponder];
    }
}


-(void)textFieldDidBeginEditing:(UITextField *)textField {
    if (!textField.inputAccessoryView) {
        textField.inputAccessoryView = [self keyboardToolBar];
    }
}

Answer 1

这是一个 UIViewController 扩展，每当我需要一组 UITextField 以通过输入配件提供导航时，我都会使用它。无需使用此方法的 UITextField 委托(delegate)，将行为添加到多个表单就变成了单行代码。还支持关闭“完成”按钮。

extension UIViewController {
  func addInputAccessoryForTextFields(textFields: [UITextField], dismissable: Bool = true, previousNextable: Bool = false) {
    for (index, textField) in textFields.enumerated() {
      let toolbar: UIToolbar = UIToolbar()
      toolbar.sizeToFit()

      var items = [UIBarButtonItem]()
      if previousNextable {
        let previousButton = UIBarButtonItem(image: UIImage(named: "Backward Arrow"), style: .plain, target: nil, action: nil)
        previousButton.width = 30
        if textField == textFields.first {
          previousButton.isEnabled = false
        } else {
          previousButton.target = textFields[index - 1]
          previousButton.action = #selector(UITextField.becomeFirstResponder)
        }

        let nextButton = UIBarButtonItem(image: UIImage(named: "Forward Arrow"), style: .plain, target: nil, action: nil)
        nextButton.width = 30
        if textField == textFields.last {
          nextButton.isEnabled = false
        } else {
          nextButton.target = textFields[index + 1]
          nextButton.action = #selector(UITextField.becomeFirstResponder)
        }
        items.append(contentsOf: [previousButton, nextButton])
      }

      let spacer = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: nil, action: nil)
      let doneButton = UIBarButtonItem(barButtonSystemItem: .done, target: view, action: #selector(UIView.endEditing))
      items.append(contentsOf: [spacer, doneButton])


      toolbar.setItems(items, animated: false)
      textField.inputAccessoryView = toolbar
    }
  }
}

例子:

let field1 = UITextField()
let field2 = UITextField()
addInputAccessoryForTextFields([field1, field2], dismissable: true, previousNextable: true)

这是一个合理的 arrow icon .