I encountered a problem recently, which was to change the default underline bar of an edittext from a default blackish color to white.
I used this solution, which seemed to me the best practices by changing the style of the EditText :
EditText
<android.support.v7.widget.AppCompatEditText
    android:id="@+id/nom"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:hint="@string/Activity_Main_EditText_Nom"
    android:imeOptions="actionNext"
    android:paddingBottom="10dp"
    android:paddingLeft="10dp"
    android:paddingRight="10dp"
    android:paddingTop="10dp"
    android:textColor="@android:color/white"
    android:textColorHint="@color/activityBackground"
    android:theme="@style/EditTextStyle"
    android:visibility="gone"
/>
style.xml
<style name="MyTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <item name="android:windowDisablePreview">true</item>
    <item name="android:windowBackground">@color/activityBackground</item>
    <item name="windowActionBar">false</item>
    <item name="actionMenuTextColor">@android:color/white</item>
    <item name="android:windowNoTitle">true</item>
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
</style>
<style name="EditTextStyle" parent="Widget.AppCompat.EditText">
    <item name="colorControlNormal">@android:color/white</item>
    <item name="colorControlActivated">@color/colorAccent</item>
    <item name="colorControlHighlight">@color/colorAccent</item>
</style>
It worked ! But it also added to the handles of the EditText an underline bar...
Any ideas ?
Answer
By discussing with @rafsanahmad007, we finally got to a final solution.
style.xml
<resources>
    <style name="MyTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <item name="android:windowDisablePreview">true</item>
        <item name="android:windowBackground">@color/activityBackground</item>
        <item name="windowActionBar">false</item>
        <item name="actionMenuTextColor">@android:color/white</item>
        <item name="android:windowNoTitle">true</item>
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>
    <style name="MyTheme.EditText" parent="MyTheme">
        <item name="colorControlNormal">@android:color/white</item>
        <item name="colorControlActivated">@color/colorAccent</item>
        <item name="colorControlHighlight">@color/colorAccent</item>
    </style>
</resources>
Apply MyTheme to application, as usual. When you want to tweak an EditText just add to it :
EditText
<EditText
     ...
     android:theme="@style/MyTheme.EditText"
     ...
/>
