Xamarin.forms物料输入占位符大小

在我的xamarin.forms应用程序中，我使用的是由xamarin提供的材料条目。该控件工作正常。但是我如何更改占位符的字体大小呢？在ios中占位符的字体大小是完美的，但在android中它要大得多。此外，条目的下划线在左侧稍多一些。如何缩小间距并将占位符和下划线对齐（参见图）

我所做的

我正在努力实现的目标

我的条目

<Entry x:Name="CustomerEntry" Visual="Material"  FontSize="Small" Placeholder="Customer Name"  HorizontalOptions="FillAndExpand" BackgroundColor="Transparent"  TextColor="White" PlaceholderColor="White" Margin="0,0,0,0"  ></Entry>

---

非常感谢您对字体大小的任何帮助，我相信您需要自定义渲染。有关如何执行此操作的详细信息，请参阅。请确保从中继承

为了解决左对齐问题，我找不到一个适用于Android和iOS的好解决方案，所以我所做的是将条目的左边距吸过来，然后使用方框视图覆盖下划线，使所有内容看起来都是左对齐的。我必须在多个地方执行此操作，因此我创建了一个自定义控件。这样做的缺点是将所有绑定都传递给用户

我的自定义控件Xaml：

<?xml version="1.0" encoding="UTF-8" ?>
<Grid x:Class="x.x.x.Controls.MaterialControls.MaterialEntry"
      xmlns="http://xamarin.com/schemas/2014/forms"
      xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
      x:Name="MaterialEntryComponent"
      Margin="-16,0,0,0"
      Focused="OnComponentFocused">
    <Entry x:Name="MaterialEntryEntry"
           Grid.Row="0"
           BackgroundColor="{Binding EntryBackgroundColor}"
           BindingContext="{x:Reference MaterialEntryComponent}"
           Completed="OnEntryCompleted"
           FontFamily="{Binding FontFamily}"
           FontSize="{Binding FontSize}"
           IsPassword="{Binding IsPassword}"
           IsSpellCheckEnabled="{Binding IsSpellCheckEnabled}"
           IsTextPredictionEnabled="{Binding IsTextPredictionEnabled}"
           Keyboard="{Binding Keyboard}"
           MaxLength="{Binding MaxLength}"
           Placeholder="{Binding Placeholder}"
           PlaceholderColor="{Binding PlaceholderColor}"
           ReturnType="{Binding ReturnType}"
           Text="{Binding Text}"
           TextChanged="OnEntryTextChanged"
           TextColor="{Binding TextColor}"
           Visual="Material" />
    <BoxView Grid.Row="0"
             Margin="{OnPlatform iOS='0,0,0,-1'}"
             BackgroundColor="{Binding EntryBackgroundColor}"
             BindingContext="{x:Reference MaterialEntryComponent}"
             HorizontalOptions="Start"
             VerticalOptions="FillAndExpand"
             WidthRequest="16" />

</Grid>

---

您也可以尝试使用XF.素材库：@ CherryBu，它仍然有下划线的问题，您可以考虑创建自定义控件来实现这一点，比如：但是，您可以更改LabelTitle.TranslationX。

using System;
using System.Windows.Input;
using Xamarin.Forms;
using Xamarin.Forms.Xaml;

namespace x.x.x.Controls.MaterialControls
{
    /// <summary>
    /// Code behind for the Material Entry control.
    /// </summary>
    [XamlCompilation(XamlCompilationOptions.Compile)]
    public partial class MaterialEntry : Grid
    {
        #region Event Handlers
        /// <summary>
        /// Completed event. Fires when the return key on the keyboard is pressed.
        /// </summary>
        public event EventHandler Completed;

        /// <summary>
        /// Text changed event. Fires when the text on the entry control is changed.
        /// </summary>
        public event EventHandler<TextChangedEventArgs> TextChanged;
        #endregion

        #region Bindable Properties
        /// <summary>
        /// Bindable property for the entry background color on the view.
        /// </summary>
        public static readonly BindableProperty EntryBackgroundColorProperty =
            BindableProperty.Create(nameof(EntryBackgroundColor), typeof(Color), typeof(MaterialEntry), Color.White);

        /// <summary>
        /// Bindable property for the font family of the entry on the view..
        /// </summary>
        public static readonly BindableProperty FontFamilyProperty =
            BindableProperty.Create(nameof(FontFamily), typeof(string), typeof(MaterialEntry), default(string));

        /// <summary>
        /// Bindable property for the font size of the entry on the view..
        /// </summary>
        public static readonly BindableProperty FontSizeProperty =
            BindableProperty.Create(nameof(FontSize), typeof(double), typeof(MaterialEntry), 12.0);

        /// <summary>
        /// Bindable property for the IsPassword of the entry on the view.
        /// </summary>
        public static readonly BindableProperty IsPasswordProperty =
            BindableProperty.Create(nameof(IsPassword), typeof(bool), typeof(MaterialEntry), false);

        /// <summary>
        /// Bindable property for the IsSpellCheckEnabled of the entry on the view.
        /// </summary>
        public static readonly BindableProperty IsSpellCheckEnabledProperty =
            BindableProperty.Create(nameof(IsSpellCheckEnabled), typeof(bool), typeof(MaterialEntry), true);

        /// <summary>
        /// Bindable property for the IsTextPredictionEnabled of the entry on the view.
        /// </summary>
        public static readonly BindableProperty IsTextPredictionEnabledProperty =
            BindableProperty.Create(nameof(IsTextPredictionEnabled), typeof(bool), typeof(MaterialEntry), true);

        /// <summary>
        /// Bindable property for the keyboard type of the entry on the view.
        /// </summary>
        public static readonly BindableProperty KeyboardProperty =
            BindableProperty.Create(nameof(Keyboard), typeof(Keyboard), typeof(MaterialEntry), Keyboard.Default);

        /// <summary>
        /// Bindable property for the MaxLength of the entry on the view..
        /// </summary>
        public static readonly BindableProperty MaxLengthProperty =
            BindableProperty.Create(nameof(MaxLength), typeof(int), typeof(MaterialEntry), int.MaxValue);

        /// <summary>
        /// Bindable property for the placeholder text of the entry on the view.
        /// </summary>
        public static readonly BindableProperty PlaceholderProperty =
            BindableProperty.Create(nameof(Placeholder), typeof(string), typeof(MaterialEntry), default(string));

        /// <summary>
        /// Bindable property for the placeholder text color of the entry on the view.
        /// </summary>
        public static readonly BindableProperty PlaceholderColorProperty =
            BindableProperty.Create(nameof(PlaceholderColor), typeof(Color), typeof(MaterialEntry), Color.Black);

        /// <summary>
        /// Bindable property for the return command of the entry on the view.
        /// </summary>
        public static readonly BindableProperty ReturnCommandProperty =
            BindableProperty.Create(nameof(ReturnCommand), typeof(ICommand), typeof(Entry), default(ICommand));

        /// <summary>
        /// Bindable property for the return command parameter of the entry on the view.
        /// </summary>
        public static readonly BindableProperty ReturnCommandParameterProperty =
            BindableProperty.Create(nameof(ReturnCommandParameter), typeof(object), typeof(Entry), default(object));

        /// <summary>
        /// Bindable property for the return type of the entry on the view.
        /// </summary>
        public static readonly BindableProperty ReturnTypeProperty =
            BindableProperty.Create(nameof(ReturnType), typeof(ReturnType), typeof(Entry), ReturnType.Default);

        /// <summary>
        /// Bindable property for the text of the entry on the view.
        /// </summary>
        public static readonly BindableProperty TextProperty =
            BindableProperty.Create(nameof(Text), typeof(string), typeof(MaterialEntry), default(string), BindingMode.TwoWay);

        /// <summary>
        /// Bindable property for the text color of the entry on the view.
        /// </summary>
        public static readonly BindableProperty TextColorProperty =
            BindableProperty.Create(nameof(TextColor), typeof(Color), typeof(MaterialEntry), Color.Black);
        #endregion

        #region Properties
        /// <summary>
        /// The background color of the entry control. Default is <see cref="Color.White"/>.
        /// </summary>
        public Color EntryBackgroundColor
        {
            get => (Color)GetValue(EntryBackgroundColorProperty);
            set => SetValue(EntryBackgroundColorProperty, value);
        }

        /// <summary>
        /// The font family for the entry control to use.
        /// </summary>
        public string FontFamily
        {
            get => (string)GetValue(FontFamilyProperty);
            set => SetValue(FontFamilyProperty, value);
        }

        /// <summary>
        /// The font size of the entry control. Default is 12.0.
        /// </summary>
        [TypeConverter(typeof(FontSizeConverter))]
        public double FontSize
        {
            get => (double)GetValue(FontSizeProperty);
            set => SetValue(FontSizeProperty, value);
        }

        /// <summary>
        /// Set if the entry field is a password field. Default is false.
        /// </summary>
        public bool IsPassword
        {
            get => (bool)GetValue(IsPasswordProperty);
            set => SetValue(IsPasswordProperty, value);
        }

        /// <summary>
        /// Set if spell check is enabled on the entry. Default is True.
        /// </summary>
        public bool IsSpellCheckEnabled
        {
            get => (bool)GetValue(IsSpellCheckEnabledProperty);
            set => SetValue(IsSpellCheckEnabledProperty, value);
        }

        /// <summary>
        /// Set if text prediction is enabled on the entry. Default is True.
        /// </summary>
        public bool IsTextPredictionEnabled
        {
            get => (bool)GetValue(IsTextPredictionEnabledProperty);
            set => SetValue(IsTextPredictionEnabledProperty, value);
        }

        /// <summary>
        /// The type of keyboard to use for the entry control. Default is <see cref="Keyboard.Default"/>.
        /// </summary>
        public Keyboard Keyboard
        {
            get => (Keyboard)GetValue(KeyboardProperty);
            set => SetValue(KeyboardProperty, value);
        }

        /// <summary>
        /// The maximum allowed length of input for the entry. Default is <see cref="int.MaxValue"/>.
        /// </summary>
        public int MaxLength
        {
            get => (int)GetValue(MaxLengthProperty);
            set => SetValue(MaxLengthProperty, value);
        }

        /// <summary>
        /// The text to use for the placeholder.
        /// </summary>
        public string Placeholder
        {
            get => (string)GetValue(PlaceholderProperty);
            set => SetValue(PlaceholderProperty, value);
        }

        /// <summary>
        /// The color of the placeholder text. Default is <see cref="Color.Black"/>.
        /// </summary>
        public Color PlaceholderColor
        {
            get => (Color)GetValue(PlaceholderColorProperty);
            set => SetValue(PlaceholderColorProperty, value);
        }

        /// <summary>
        ///  The command that fires when the return button on the keyboard is tapped.
        /// </summary>
        public ICommand ReturnCommand
        {
            get => (ICommand)GetValue(ReturnCommandProperty);
            set => SetValue(ReturnCommandProperty, value);
        }

        /// <summary>
        /// The parameter to pass with the return command.
        /// </summary>
        public object ReturnCommandParameter
        {
            get => GetValue(ReturnCommandParameterProperty);
            set => SetValue(ReturnCommandParameterProperty, value);
        }

        /// <summary>
        /// The type of return button to display on the keyboard. Default is <see cref="ReturnType.Default"/>.
        /// </summary>
        public ReturnType ReturnType
        {
            get => (ReturnType)GetValue(ReturnTypeProperty);
            set => SetValue(ReturnTypeProperty, value);
        }

        /// <summary>
        /// The text of the entry.
        /// </summary>
        public string Text
        {
            get => (string)GetValue(TextProperty);
            set => SetValue(TextProperty, value);
        }

        /// <summary>
        /// The color of the text. Default is <see cref="Color.Black"/>.
        /// </summary>
        public Color TextColor
        {
            get => (Color)GetValue(TextColorProperty);
            set => SetValue(TextColorProperty, value);
        }
        #endregion

        /// <summary>
        /// Constructor.
        /// </summary>
        public MaterialEntry()
        {
            InitializeComponent();
        }

        #region Methods
        /// <summary>
        /// Focuses the entry control.
        /// </summary>
        public void FocusEntry()
        {
            MaterialEntryEntry.Focus();
        }

        private void OnEntryCompleted(object sender, EventArgs e)
        {
            SendCompleted();
        }

        private void OnEntryTextChanged(object sender, TextChangedEventArgs e)
        {
            TextChanged?.Invoke(this, e);
        }

        private void SendCompleted()
        {
            if (IsEnabled)
            {
                Completed?.Invoke(this, EventArgs.Empty);

                if (ReturnCommand != null && ReturnCommand.CanExecute(ReturnCommandParameter))
                {
                    ReturnCommand.Execute(ReturnCommandParameter);
                }
            }
        }

        private void OnComponentFocused(object sender, FocusEventArgs e)
        {
            FocusEntry();
        }
        #endregion
    }
}

<material:MaterialEntry Placeholder="Do something amazing"
                        Style="{StaticResource EntryStyle}"
                        Text="{Binding MyEntryText}" />