You can change these things in the values / colors.xml file
<resources>
<color name="primary">#3F51B5</color>
<color name="primary_dark">#303F9F</color>
<color name="primary_light">#C5CAE9</color>
<color name="accent">#00BCD4</color>
<color name="primary_text">#212121</color>
<color name="secondary_text">#727272</color>
<color name="icons">#FFFFFF</color>
<color name="divider">#B6B6B6</color>
</resources>
More information:
link
link
You can create style:
<style name="green">
<item name="main_background">@drawable/background_green</item>
<item name="colorPrimaryDark">@color/colorPrimaryDark</item>
<item name="button_light">@color/button_light</item>
</style>
And set yourself in the code:
activity.setTheme(R.style.green);
More information:
link