Change the On/Off text of a toggle button Android

In the example you link to, they are changing it to Day/Night by using android:textOn and android:textOff

You can use the following to set the text from the code:

toggleButton.setText(textOff);
// Sets the text for when the button is first created.

toggleButton.setTextOff(textOff);
// Sets the text for when the button is not in the checked state.

toggleButton.setTextOn(textOn);
// Sets the text for when the button is in the checked state.

To set the text using xml, use the following:

android:textOff="The text for the button when it is not checked."
android:textOn="The text for the button when it is checked." 

This information is from here

Set the XML as:

<ToggleButton
    android:id="@+id/flashlightButton"
    style="@style/Button"
    android:layout_above="@+id/buttonStrobeLight"
    android:layout_marginBottom="20dp"
    android:onClick="onToggleClicked"
    android:text="ToggleButton"
    android:textOn="Light ON"
    android:textOff="Light OFF" />