I'm testing my app on Samsung Galaxy S3, which has two touch buttons the back button and the menu button
I set soundEffectsEnabled to false to all of my root views, and tried with making a custom theme (as pointed out in here) and setting that theme on the application's manifest file (I tried adding it to each Activity element, too). No success.
Here is my xml file in res/values:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<style name="MyCustomTheme" parent="@android:style/Theme.NoTitleBar.Fullscreen">
<item name="android:soundEffectsEnabled">false</item>
</style>
</resources>
And the opening tag of my Application element:
<application
android:icon="@drawable/icon"
android:label="@string/app_name"
android:theme="@style/MyCustomTheme" >
It builds and runs properly. NoTitleBar.Fullscreen works too, but the back and menu touch buttons play the sound still.