Is it possible to have dynamic resource path when using Android data-binding?

Question

I am using data-binding in my Android application, and I want to change the font color depending on what state my model is in. Something like

android:textColor='@{@color/state_ + myobj.state}'

in my layout. And

<color name="state_good">#0f0</color>

in my colors.xml. Is something like this possible?

Answer 1

I can think of two main possibilities.

The one that you probably don't want is to have your model object have a getter method that returns the color resource ID (based on its state). While this is simple, it would violate your typical view/model separation of concerns, as the model shouldn't really care about rendering colors.

The other is to have a utility class somewhere, with a static method that, given the state, returns the color resource ID. You can then import that class into the <layout> and call it from the expression.

For example, this layout imports Html , to be able to call Html.fromHtml() , to handle strings that may have HTML formatting (or, in this case, HTML entities):

<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android">

  <data>

    <import type="android.text.Html"/>

    <variable
      name="item"
      type="com.commonsware.android.databind.basic.Item"/>
  </data>

  <LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal">

    <ImageView
      android:id="@+id/icon"
      android:layout_width="@dimen/icon"
      android:layout_height="@dimen/icon"
      android:layout_gravity="center_vertical"
      android:contentDescription="@string/icon"
      android:padding="8dip"/>

    <TextView
      android:id="@+id/title"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_gravity="left|center_vertical"
      android:text="@{Html.fromHtml(item.title)}"
      android:textSize="20sp"/>

  </LinearLayout>
</layout>

In your case, you would import your utility class and call your static method in the android:textColor attribute.