Create buttun_text.xml in res/color folder and define color when button is pressed. Add this xml reference in your main layout xml.
buttun_text.xml
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
<item android:state_pressed="true"
android:color="#ff00ff00"/> <!-- pressed -->
<item android:state_focused="true"
android:color="#ff0000ff"/> <!-- focused -->
<item android:color="#ff000000"/> <!-- default -->
</selector>
activity_main.xml
<TableRow>
<TextView
android:id="@+id/btn1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:clickable="true"
android:textColor="@color/button_text" <!-- add text color xml here -->
android:text="1" />
<TextView
android:id="@+id/btn2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:clickable="true"
android:textColor="@color/button_text" <!-- add text color xml here -->
android:text="2" />
.
.
.