Xamarin.iOS 为 UITextField/ViewDidAppear 的底部绘制边框为时已晚
Xamarin.iOS Draw a Border for bottom of the UITextField / ViewDidAppear is too late
我正在 Xamarin.iOs 中编码,我想为 UITextField 的底部添加边框。
所以很简单,我用谷歌搜索了一下(我将其个性化为 Xamarin.ios 并且)我从 link.
中获得了这段代码
UITextField _textField = new UITextField();
_textField.Placeholder = placeHolder;
_textField.AutocapitalizationType = autocap.Value;
_textField.AutocorrectionType = uitextAutocorrect.Value;
_textField.BorderStyle = borderstyle.Value;
_textField.SecureTextEntry = secureTextEntry.Value;
_textField.KeyboardType = uiKeyboardType.Value;
return _textField;
如您所知,我不能将这部分代码放入 ViewController 的构造函数中,也不能放入 ViewWillAppear 中。所以我必须把它放在 ViewDidAppear 中,BUT 来不及了,这意味着当我 运行 ViewController 时,它显示无边框的 textField,并且紧接着几毫秒后,边界就会出现,这对我来说太晚了。
对这个显示问题有什么想法吗?
编辑:
所以我更详细地问了我的问题:
这是我的完整代码:
public class 更改密码ViewController: UIViewController
{
//私人MainViewModel _viewModel;
private UILabel _oldPasswordLabel;
private UITextField _oldPasswordTextField;
private UILabel _newPasswordLabel;
private UITextField _newPasswordTextField;
private UILabel _confirmPasswordLabel;
private UITextField _confirmPasswordTextField;
private User currentUser;
private UIButton _saveNewPassworBtn;
public ChangePasswordViewController(User user)
{
currentUser = user;
}
private void _saveNewPassworBtn_TouchUpInside(object sender, EventArgs e)
{
//do sth
}
public override void ViewDidLoad()
{
base.ViewDidLoad();
// Perform any additional setup after loading the view, typically from a nib.
//_viewModel = new MainViewModel();
Title = Texts.ChangePassword;
View.BackgroundColor = UIColor.White;
_oldPasswordLabel = InitUILabel(Texts.OldPasswordTxt, alignment: UITextAlignment.Right);
_oldPasswordLabel.Font = UIFont.BoldSystemFontOfSize(14);
_oldPasswordLabel.AdjustsFontSizeToFitWidth = true;
_oldPasswordTextField = InitUITextField(Texts.OldPassword, secureTextEntry: true);
this._oldPasswordTextField.ShouldReturn += (textField) => {
_newPasswordTextField.BecomeFirstResponder();
return true;
};
_oldPasswordTextField.BorderStyle = UITextBorderStyle.None;
_newPasswordLabel = InitUILabel(Texts.NewPasswordTxt, alignment: UITextAlignment.Right);
_newPasswordLabel.Font = UIFont.BoldSystemFontOfSize(14);
_newPasswordTextField = InitUITextField(Texts.NewPassword, secureTextEntry: true);
this._newPasswordTextField.ShouldReturn += (textField) => {
_confirmPasswordTextField.BecomeFirstResponder();
return true;
};
_newPasswordTextField.BorderStyle = UITextBorderStyle.None;
_confirmPasswordLabel = InitUILabel(Texts.ConfirmPasswordTxt, alignment: UITextAlignment.Right);
_confirmPasswordLabel.Font = UIFont.BoldSystemFontOfSize(14);
_confirmPasswordTextField = InitUITextField(Texts.NewPassword, secureTextEntry: true);
this._confirmPasswordTextField.ShouldReturn += (textField) => {
textField.ResignFirstResponder();
return true;
};
_confirmPasswordTextField.BorderStyle = UITextBorderStyle.None;
_saveNewPassworBtn = InitUIButton(Texts.Save, _saveNewPassworBtn_TouchUpInside, Colors.MainColor, UIColor.White);
View.AddSubviews(_oldPasswordLabel, _oldPasswordTextField, _newPasswordLabel, _newPasswordTextField,
_saveNewPassworBtn, _confirmPasswordLabel, _confirmPasswordTextField);
//
//constraints
var hMargin = 10;
var hMiniMargin = 5;
var vMargin = 10;
View.SubviewsDoNotTranslateAutoresizingMaskIntoConstraints();
View.AddConstraints(
_oldPasswordLabel.AtTopOf(View, 100),
_oldPasswordLabel.AtLeftOf(View, hMargin),
_oldPasswordTextField.Below(_oldPasswordLabel, hMiniMargin),
_oldPasswordTextField.AtLeftOf(View, hMargin),
_oldPasswordTextField.WithSameWidth(View).Minus(hMargin * 2),
_newPasswordLabel.Below(_oldPasswordTextField, vMargin),
_newPasswordLabel.AtLeftOf(View, hMargin),
_newPasswordTextField.Below(_newPasswordLabel, hMiniMargin),
_newPasswordTextField.AtLeftOf(View, hMargin),
_newPasswordTextField.WithSameWidth(View).Minus(hMargin * 2),
_confirmPasswordLabel.Below(_newPasswordTextField, vMargin),
_confirmPasswordLabel.AtLeftOf(View, hMargin),
_confirmPasswordTextField.Below(_confirmPasswordLabel, hMiniMargin),
_confirmPasswordTextField.AtLeftOf(View, hMargin),
_confirmPasswordTextField.WithSameWidth(View).Minus(hMargin * 2),
_saveNewPassworBtn.Below(_confirmPasswordTextField, vMargin * 3),
_saveNewPassworBtn.WithSameWidth(View).Minus(20),
_saveNewPassworBtn.AtLeftOf(View, 10)
);
_newPasswordTextField = SetBottomBorderLine(_newPasswordTextField);
_confirmPasswordTextField = SetBottomBorderLine(_confirmPasswordTextField);
_oldPasswordTextField = SetBottomBorderLine(_oldPasswordTextField);
}
public override void ViewWillAppear(bool animated)
{
base.ViewWillAppear(animated);
this.NavigationItem.SetLeftBarButtonItem(new UIBarButtonItem(Texts.Cancel,UIBarButtonItemStyle.Plain, (sender, args) =>
{
this.NavigationController.SetNavigationBarHidden(false, false);
this.NavigationController.PushViewController(new ProfileViewController(), false);
}), true);
}
public override void ViewDidAppear(bool animated)
{
base.ViewDidAppear(animated);
}
}
在这些行中:
_newPasswordTextField = SetBottomBorderLine(_newPasswordTextField);
_confirmPasswordTextField = SetBottomBorderLine(_confirmPasswordTextField);
_oldPasswordTextField = SetBottomBorderLine(_oldPasswordTextField);
我为我的文本字段设置了边框但是!如果我将这些行放在 ViewDidLoad 或 ViewWillAppear 或 ViewDidLayoutSubviews 中,它不会显示更改,如果我将它们放在 ViewDidAppear 中,它会完美显示并延迟几毫秒(在显示我的页面内容之后!!!)。你有什么解决办法吗?
使用Cirrious.FluentLayouts
.
造成的
当我们在 ViewDidLoad
中设置 Constraints 时,那些控件将不会在 ViewDidAppear
之前完成渲染。
打印ViewDidLoad
、ViewWillAppear
、ViewDidAppear
中那些textfields的frame,可以发现只有ViewDidAppear
中的frame不等于(0,0 ,0,0).
解决问题,可以在ViewDidLoad
中加入View.LayoutIfNeeded
强制更新视图
View.AddConstraints(
//xxx
);
View.LayoutIfNeeded(); //Add this
_newPasswordTextField = SetBottomBorderLine(_newPasswordTextField);
_confirmPasswordTextField = SetBottomBorderLine(_confirmPasswordTextField);
_oldPasswordTextField = SetBottomBorderLine(_oldPasswordTextField);
我正在 Xamarin.iOs 中编码,我想为 UITextField 的底部添加边框。
所以很简单,我用谷歌搜索了一下(我将其个性化为 Xamarin.ios 并且)我从 link.
中获得了这段代码UITextField _textField = new UITextField();
_textField.Placeholder = placeHolder;
_textField.AutocapitalizationType = autocap.Value;
_textField.AutocorrectionType = uitextAutocorrect.Value;
_textField.BorderStyle = borderstyle.Value;
_textField.SecureTextEntry = secureTextEntry.Value;
_textField.KeyboardType = uiKeyboardType.Value;
return _textField;
如您所知,我不能将这部分代码放入 ViewController 的构造函数中,也不能放入 ViewWillAppear 中。所以我必须把它放在 ViewDidAppear 中,BUT 来不及了,这意味着当我 运行 ViewController 时,它显示无边框的 textField,并且紧接着几毫秒后,边界就会出现,这对我来说太晚了。
对这个显示问题有什么想法吗?
编辑:
所以我更详细地问了我的问题:
这是我的完整代码:
public class 更改密码ViewController: UIViewController { //私人MainViewModel _viewModel;
private UILabel _oldPasswordLabel;
private UITextField _oldPasswordTextField;
private UILabel _newPasswordLabel;
private UITextField _newPasswordTextField;
private UILabel _confirmPasswordLabel;
private UITextField _confirmPasswordTextField;
private User currentUser;
private UIButton _saveNewPassworBtn;
public ChangePasswordViewController(User user)
{
currentUser = user;
}
private void _saveNewPassworBtn_TouchUpInside(object sender, EventArgs e)
{
//do sth
}
public override void ViewDidLoad()
{
base.ViewDidLoad();
// Perform any additional setup after loading the view, typically from a nib.
//_viewModel = new MainViewModel();
Title = Texts.ChangePassword;
View.BackgroundColor = UIColor.White;
_oldPasswordLabel = InitUILabel(Texts.OldPasswordTxt, alignment: UITextAlignment.Right);
_oldPasswordLabel.Font = UIFont.BoldSystemFontOfSize(14);
_oldPasswordLabel.AdjustsFontSizeToFitWidth = true;
_oldPasswordTextField = InitUITextField(Texts.OldPassword, secureTextEntry: true);
this._oldPasswordTextField.ShouldReturn += (textField) => {
_newPasswordTextField.BecomeFirstResponder();
return true;
};
_oldPasswordTextField.BorderStyle = UITextBorderStyle.None;
_newPasswordLabel = InitUILabel(Texts.NewPasswordTxt, alignment: UITextAlignment.Right);
_newPasswordLabel.Font = UIFont.BoldSystemFontOfSize(14);
_newPasswordTextField = InitUITextField(Texts.NewPassword, secureTextEntry: true);
this._newPasswordTextField.ShouldReturn += (textField) => {
_confirmPasswordTextField.BecomeFirstResponder();
return true;
};
_newPasswordTextField.BorderStyle = UITextBorderStyle.None;
_confirmPasswordLabel = InitUILabel(Texts.ConfirmPasswordTxt, alignment: UITextAlignment.Right);
_confirmPasswordLabel.Font = UIFont.BoldSystemFontOfSize(14);
_confirmPasswordTextField = InitUITextField(Texts.NewPassword, secureTextEntry: true);
this._confirmPasswordTextField.ShouldReturn += (textField) => {
textField.ResignFirstResponder();
return true;
};
_confirmPasswordTextField.BorderStyle = UITextBorderStyle.None;
_saveNewPassworBtn = InitUIButton(Texts.Save, _saveNewPassworBtn_TouchUpInside, Colors.MainColor, UIColor.White);
View.AddSubviews(_oldPasswordLabel, _oldPasswordTextField, _newPasswordLabel, _newPasswordTextField,
_saveNewPassworBtn, _confirmPasswordLabel, _confirmPasswordTextField);
//
//constraints
var hMargin = 10;
var hMiniMargin = 5;
var vMargin = 10;
View.SubviewsDoNotTranslateAutoresizingMaskIntoConstraints();
View.AddConstraints(
_oldPasswordLabel.AtTopOf(View, 100),
_oldPasswordLabel.AtLeftOf(View, hMargin),
_oldPasswordTextField.Below(_oldPasswordLabel, hMiniMargin),
_oldPasswordTextField.AtLeftOf(View, hMargin),
_oldPasswordTextField.WithSameWidth(View).Minus(hMargin * 2),
_newPasswordLabel.Below(_oldPasswordTextField, vMargin),
_newPasswordLabel.AtLeftOf(View, hMargin),
_newPasswordTextField.Below(_newPasswordLabel, hMiniMargin),
_newPasswordTextField.AtLeftOf(View, hMargin),
_newPasswordTextField.WithSameWidth(View).Minus(hMargin * 2),
_confirmPasswordLabel.Below(_newPasswordTextField, vMargin),
_confirmPasswordLabel.AtLeftOf(View, hMargin),
_confirmPasswordTextField.Below(_confirmPasswordLabel, hMiniMargin),
_confirmPasswordTextField.AtLeftOf(View, hMargin),
_confirmPasswordTextField.WithSameWidth(View).Minus(hMargin * 2),
_saveNewPassworBtn.Below(_confirmPasswordTextField, vMargin * 3),
_saveNewPassworBtn.WithSameWidth(View).Minus(20),
_saveNewPassworBtn.AtLeftOf(View, 10)
);
_newPasswordTextField = SetBottomBorderLine(_newPasswordTextField);
_confirmPasswordTextField = SetBottomBorderLine(_confirmPasswordTextField);
_oldPasswordTextField = SetBottomBorderLine(_oldPasswordTextField);
}
public override void ViewWillAppear(bool animated)
{
base.ViewWillAppear(animated);
this.NavigationItem.SetLeftBarButtonItem(new UIBarButtonItem(Texts.Cancel,UIBarButtonItemStyle.Plain, (sender, args) =>
{
this.NavigationController.SetNavigationBarHidden(false, false);
this.NavigationController.PushViewController(new ProfileViewController(), false);
}), true);
}
public override void ViewDidAppear(bool animated)
{
base.ViewDidAppear(animated);
}
}
在这些行中:
_newPasswordTextField = SetBottomBorderLine(_newPasswordTextField); _confirmPasswordTextField = SetBottomBorderLine(_confirmPasswordTextField); _oldPasswordTextField = SetBottomBorderLine(_oldPasswordTextField);
我为我的文本字段设置了边框但是!如果我将这些行放在 ViewDidLoad 或 ViewWillAppear 或 ViewDidLayoutSubviews 中,它不会显示更改,如果我将它们放在 ViewDidAppear 中,它会完美显示并延迟几毫秒(在显示我的页面内容之后!!!)。你有什么解决办法吗?
使用Cirrious.FluentLayouts
.
当我们在 ViewDidLoad
中设置 Constraints 时,那些控件将不会在 ViewDidAppear
之前完成渲染。
打印ViewDidLoad
、ViewWillAppear
、ViewDidAppear
中那些textfields的frame,可以发现只有ViewDidAppear
中的frame不等于(0,0 ,0,0).
解决问题,可以在ViewDidLoad
中加入View.LayoutIfNeeded
强制更新视图
View.AddConstraints(
//xxx
);
View.LayoutIfNeeded(); //Add this
_newPasswordTextField = SetBottomBorderLine(_newPasswordTextField);
_confirmPasswordTextField = SetBottomBorderLine(_confirmPasswordTextField);
_oldPasswordTextField = SetBottomBorderLine(_oldPasswordTextField);