Question

How do you save a theme in preferences without defining a constant for each theme?

The style resource id is pretty straightforward to get and save, but also likely to change in an update.

The style name seems a better option. If that’s the way to do it, how do you get the theme name given its resource id, and how do you get the resource id given the theme’s name?

Answer 1

I manage to solve this by using the theme name and getResourceEntryName. Full code:

public static final String PREFERENCE_THEME = "theme";
public static final int[] THEMES = {R.style.Theme_Blue, R.style.Theme_Green, R.style.Theme_Orange, R.style.Theme_Purple, R.style.Theme_Red};
private static final int DEFAULT_THEME = R.style.Theme_Green;

public int getTheme() {
    final String themeName = preferences.getString(PREFERENCE_THEME, getThemeName(DEFAULT_THEME));
    for (int i = 0; i < THEMES.length; i++) {
        int resId = THEMES[i];
        String candidateThemeName = this.getThemeName(resId);
        if (themeName.equals(candidateThemeName)) {
            return resId;
        }
    }
    // The theme in preferences doesn't exist anymore
    this.setTheme(DEFAULT_THEME);
    return DEFAULT_THEME;
}

public void setTheme(int resId) {
    final String themeName = getThemeName(resId);
    Editor editor = preferences.edit();
    editor.putString(PREFERENCE_THEME, themeName);
    editor.commit();
}

private String getThemeName(int resId) {
    return context.getResources().getResourceEntryName(resId);
}