The best way to manage android app themes

Question

In my program I have to do switch application themes programmatically. That is, there is an option to switch light and dark themes. What is the best practice? Can I create and manage the styles set? For instance, I have this textview and button.

<Button
                android:id="@+id/btn"
                style="@style/BT_list"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="@string/OK" />

            <TextView
                android:id="@+id/tv"
                style="@style/TText"
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:text="@string/msg" />

I have this style:

<style name="BT_list">
    <item name="android:layout_width">match_parent</item>
    <item name="android:layout_height">30dp</item>
    <item name="android:textColor">@color/green_color</item>
    <item name="android:gravity">center</item>
    <item name="android:paddingLeft">0dp</item>
    <item name="android:paddingRight">0dp</item>
    <item name="android:layout_marginLeft">0dp</item>
    <item name="android:layout_marginRight">0dp</item>
    <item name="android:textSize">15sp</item>
    <item name="android:textStyle">bold</item>
    <item name="android:background">@drawable/grad</item>
</style>


<style name="TText">
    <item name="android:textColor">@color/text_color</item>
    <item name="android:background">@color/white"</item>
</style>

How can I change the values with something like setTheme(); programmatically for both (maybe more) styles?

Answer 1

You could create a preference activity that gives the user an option to change the theme. After that, in the OnCreate method of the activity you want to theme, you could use:

    SharedPreferences prefs = PreferenceManager
            .getDefaultSharedPreferences(this);
    String userTheme = prefs.getString("theme", "1");
    if (userTheme.equals("1"))
        setTheme(R.style.ThemeDark);
    else if (userTheme.equals("2"))
        setTheme(R.style.ThemeLight);

And in your Styles.xml you could add

    <style name="ThemeDark" parent="Holo.Theme">
        <!-- your changes go here -->
    </style>
   <style name="ThemeLight" parent="Holo.Theme.Light">
        <!-- your changes go here -->
    </style>

NOTE: This is my own method of theme changing used with ABS and HoloEverywhere. This will not work if you don't use these libraries