android - Set theme color dynamically

Question

I am using themes (dynamically) in my android app, like this:

my_layout.xml (extract):

<TextView
    android:id="@+id/myItem"
    style="?my_item_style" />

attrs.xml (extract):

<attr name="my_item_style" format="reference" />

themes.xml (extract):

<style name="MainTheme.Blue">
      <item name="my_item_style">@style/my_item_style_blue</item>
</style>

<style name="MainTheme.Green">
      <item name="my_item_style">@style/my_item_style_green<item>
</style>

styles.xml (extract):

<style name="my_item_style_blue">
      <item name="android:textColor">@color/my_blue</item>
</style>

<style name="my_item_style_green">
      <item name="android:textColor">@color/my_blue</item>
</style>

So, as you can see, I am setting themes dynamically. I am using this class:

public class ThemeUtils {

  private static int sTheme;
  public final static int THEME_BLUE = 1;
  public final static int THEME_GREEN = 2;

  public static void changeToTheme(MainActivity activity, int theme) {
      sTheme = theme;
      activity.startActivity(new Intent(activity, MyActivity.class));
  }

  public static void onActivityCreateSetTheme(Activity activity)
  {
      switch (sTheme)
      {
          default:
          case THEME_DEFAULT:
          case THEME_BLUE:
              activity.setTheme(R.style.MainTheme_Blue);
              break;
          case THEME_GREEN:
              activity.setTheme(R.style.MainTheme_Green);
              break;
      }
  }

}

What I want to know, is there a way how to do this (change theme color) in code? For example, I have following code (extract):

((TextView) findViewById(R.id.myItem)).setTextColor(R.color.blue);

It can be done by some helper method, which would use switch command for available themes and return correct color for a theme. But I would like to know if there is some better, nicer and faster way.

Thanks!

Answer 1

I have finally done it using following method:

public static int getColor(String colorName) {
    Context ctx = getContext();
    switch (sTheme) {
        default:
        case THEME_DEFAULT:
            return ctx.getResources().getIdentifier("BLUE_" + colorName, "color", ctx.getPackageName());
        case THEME_BLUE:
            return ctx.getResources().getIdentifier("BLUE_" + colorName, "color", ctx.getPackageName());
        case THEME_GREEN:
            return ctx.getResources().getIdentifier("GREEN_" + colorName, "color", ctx.getPackageName());
    }
}

This returns color according to my theme (I used prefixes).