问题描述
我有一个选择器。请告诉我如何更改标题的颜色,项目的颜色以及删除这些行
我有我的自定义选择器,可以更改按钮的颜色取消,确定 我试图删除线 https://forums.xamarin.com/discussion/78693/how-can-i-remove-the-picker-borders-in-forms-for-android 但它不起作用 如何更改我不知道的SELECT CAR和AUDI的颜色
解决方法
您可以使用自定义渲染器
来实现它using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Android.App;
using Android.Content;
using Android.Graphics;
using Android.Graphics.Drawables;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using App12.Droid;
using Xamarin.Forms;
using Xamarin.Forms.Platform.Android;
using Color = Android.Graphics.Color;
using Orientation = Android.Widget.Orientation;
[assembly: ExportRenderer(typeof(Picker),typeof(MyPickerRenderer))]
namespace App12.Droid
{
public class MyPickerRenderer:PickerRenderer
{
IElementController ElementController => Element;
public MyPickerRenderer(Context context) : base(context)
{
}
private AlertDialog _dialog;
protected override void OnElementChanged(ElementChangedEventArgs<Picker> e)
{
base.OnElementChanged(e);
Control.Click += Control_Click;
Control.SetHintTextColor(Android.Graphics.Color.Red);
Control.SetSingleLine(true);
Control.SetTypeface(null,TypefaceStyle.Bold);
Control.Gravity = GravityFlags.Center;
var gd = new GradientDrawable();
gd.SetStroke(0,Android.Graphics.Color.Transparent);
Control.SetBackground(gd);
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
Control.Click -= Control_Click;
//var picker = (Picker)Element;
//picker.PropertyChanged -= Control_Click;
}
base.Dispose(disposing);
}
private void Control_Click(object sender,EventArgs e)
{
Picker model = Element;
picker.SelectionDividerHeight = 0;
var picker = new TextColorNumberPicker(Context);
if (model.Items != null && model.Items.Any())
{
// set style here
picker.MaxValue = model.Items.Count - 1;
picker.MinValue = 0;
picker.SetDisplayedValues(model.Items.ToArray());
picker.WrapSelectorWheel = false;
picker.Value = model.SelectedIndex;
}
var layout = new LinearLayout(Context) { Orientation = Orientation.Vertical };
layout.AddView(picker);
var titleView = new TextView(Context);
titleView.Text = "Select a car";
titleView.TextSize = 20;
titleView.SetTextColor(Color.Red);
titleView.SetBackgroundColor(Color.White);
ElementController.SetValueFromRenderer(VisualElement.IsFocusedProperty,true);
var builder = new AlertDialog.Builder(Context);
builder.SetView(layout);
builder.SetTitle(model.Title ?? "");
builder.SetCustomTitle(titleView);
builder.SetNegativeButton("Cancel ",(s,a) =>
{
ElementController.SetValueFromRenderer(VisualElement.IsFocusedProperty,false);
// It is possible for the Content of the Page to be changed when Focus is changed.
// In this case,we'll lose our Control.
Control?.ClearFocus();
_dialog = null;
});
builder.SetPositiveButton("Ok ",a) =>
{
ElementController.SetValueFromRenderer(Picker.SelectedIndexProperty,picker.Value);
// It is possible for the Content of the Page to be changed on SelectedIndexChanged.
// In this case,the Element & Control will no longer exist.
if (Element != null)
{
if (model.Items.Count > 0 && Element.SelectedIndex >= 0)
Control.Text = model.Items[Element.SelectedIndex];
ElementController.SetValueFromRenderer(VisualElement.IsFocusedProperty,false);
// It is also possible for the Content of the Page to be changed when Focus is changed.
// In this case,we'll lose our Control.
Control?.ClearFocus();
}
_dialog = null;
});
_dialog = builder.Create();
_dialog.DismissEvent += (ssender,args) =>
{
ElementController?.SetValueFromRenderer(VisualElement.IsFocusedProperty,false);
};
_dialog.Show();
Android.Widget.Button btnOk = _dialog.GetButton((int)Android.Content.DialogButtonType.Positive);
btnOk.SetTextColor(Android.Graphics.Color.Blue);
Android.Widget.Button btnCancel = _dialog.GetButton((int)Android.Content.DialogButtonType.Positive);
btnCancel.SetTextColor(Android.Graphics.Color.Gray);
}
}
public class TextColorNumberPicker : NumberPicker
{
public TextColorNumberPicker(Context context) : base(context)
{
}
public override void AddView(Android.Views.View child,int index,ViewGroup.LayoutParams @params)
{
base.AddView(child,index,@params);
UpdateView(child);
}
public void UpdateView(Android.Views.View view)
{
if (view is EditText)
{
((EditText)view).SetTextColor(Color.Red); // set item text color
}
}
}
}