change text field hint text color code example
Example: edittext hint color
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="@dimen/dp_10"
android:textColorHint="@color/color_black" -this line-
app:hintTextAppearance="@style/TextLabel">
<EditText
android:id="@+id/et_state"
style="@style/profile_editTextStyle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="@string/billingState"
android:text="@string/billingState"
/>
</android.support.design.widget.TextInputLayout>