Styling a view with a custom style reference

问题

I'm trying to style a RelativeLayout with a custom attribute

appNS:style1="@style/RelativeLayout2"

The value of this attribute is read during construction with the static method

GetStyle(context, attributeSet)

and passed to the appropriate base constructor

public RelativeLayout2(Context context, IAttributeSet attributeSet) 
    : base(context, attributeSet, 0, GetStyle(context, attributeSet))
{
}

None of the styling in @style/RelativeLayout2 takes effect, and may be related to a separate issue defStyleRes has no effect in custom View (RelativeLayout)

Despite that, is there a more appropriate, framework supported mean to this end, since this sort of seems like a hack?

attrs.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>

  <declare-styleable name="RelativeLayout2">
    <attr name="style1" format="reference"></attr>
  </declare-styleable>

</resources>

styles.xml

<resources>

  <style name="RelativeLayout2">
    <item name="android:layout_width">40dp</item>
    <item name="android:layout_height">300dp</item>
    <item name="android:background">#114499</item>
    <item name="android:padding">50dp</item>
  </style>

</resources>

activity_main.axml

<?xml version="1.0" encoding="utf-8"?>
<InflationWithStyle.RelativeLayout2 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:appNS="http://schemas.android.com/apk/res/InflationWithStyle.InflationWithStyle"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    appNS:style1="@style/RelativeLayout2">

    <TextView
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:text="Needs more style."/>

</InflationWithStyle.RelativeLayout2>

MainActivity.cs

using Android.App;
using Android.Content;
using Android.OS;
using Android.Support.V7.App;
using Android.Runtime;
using Android.Util;
using Android.Widget;

namespace InflationWithStyle
{
    [Activity(Label = "@string/app_name", Theme = "@style/AppTheme", MainLauncher = true)]
    public class MainActivity : AppCompatActivity
    {
        protected override void OnCreate(Bundle savedInstanceState)
        {
            base.OnCreate(savedInstanceState);
            // Set our view from the "main" layout resource
            SetContentView(Resource.Layout.activity_main);
        }
    }

    public class RelativeLayout2 : RelativeLayout
    {
        public RelativeLayout2(Context context, IAttributeSet attributeSet) 
            : base(context, attributeSet, 0, GetStyle(context, attributeSet))
        {
        }

        private static int GetStyle(Context context, IAttributeSet attributeSet)
        {
            return ReadStyleAttribute(context, attributeSet);
        }

        private static int ReadStyleAttribute(Context context, IAttributeSet attributes)
        {
            Android.Content.Res.TypedArray typedArray = context.ObtainStyledAttributes(attributes, Resource.Styleable.RelativeLayout2);

            int styleAttr = typedArray.GetResourceId(Resource.Styleable.RelativeLayout2_style1, 0);

            typedArray.Recycle();

            return styleAttr;
        }
    }
}

回答1:

None of the styling in @style/RelativeLayout2 takes effect

Please refer to my answer defStyleRes has no effect in custom View (RelativeLayout).

You could try using style="@style/RelativeLayout2", it works fine on my side.

来源：https://stackoverflow.com/questions/52211138/styling-a-view-with-a-custom-style-reference

标签

android

xamarin.android