TabLayout color of selected tab underline

Use app:tabIndicatorColor.

Example:

<android.support.design.widget.TabLayout
    android:id="@+id/tabs"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:tabIndicatorColor="@android:color/white" />

Make sure you have this namespace: xmlns:app="http://schemas.android.com/apk/res-auto"

Documentation: https://developer.android.com/reference/android/support/design/widget/TabLayout.html#attr_android.support.design:tabIndicatorColor.

Try to download below file from this location :

https://github.com/google/iosched/tree/master/android/src/main/java/com/google/samples/apps/iosched/ui/widget

SlidingTabLayout.java
SlidingTabStrip.java

Try to set tab indicator color this way :

slidingTabLayout.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
     @Override
     public int getIndicatorColor(int position) {
        return getResources().getColor(R.color.color_name);
     }
});

you can use setcustomTebColorizer below is the example

mSlidingTabLayout=(SlidingTabLayout)findViewById(R.id.sliding_tabs);
        mSlidingTabLayout.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
            @Override
            public int getIndicatorColor(int position) {
                return Color.YELLOW;
            }

                @Override
                public int getDividerColor(int position) {
                    return 0;
                }
            });