I want to complete the answer from above for the people who are new to the system,
the missing xmls ( background_fill , progress_fill and progress could look like that for a gradient red
progress.xml
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
<item
android:id="@android:id/background"
android:drawable="@drawable/background_fill" />
<item android:id="@android:id/progress">
<clip android:drawable="@drawable/progress_fill" />
</item>
</layer-list>
background_fill.xml
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<gradient
android:startColor="#FF555555"
android:centerColor="#FF555555"
android:endColor="#FF555555"
android:angle="90" />
<corners android:radius="5px" />
<stroke
android:width="2dp"
android:color="#50999999" />
<stroke
android:width="1dp"
android:color="#70555555" />
</shape>
progress_fill.xml
<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<gradient
android:startColor="#FF470000"
android:centerColor="#FFB80000"
android:endColor="#FFFF4400"
android:angle="180" />
<corners android:radius="5px" />
<stroke
android:width="2dp"
android:color="#50999999" />
<stroke
android:width="1dp"
android:color="#70555555" />
</shape>
i did not complete the implementing for android:thumb, so the thumb will be still the original one
Therefore we just have to delete this line again from our layout xml where we define the seekbar
android:thumb="@drawable/thumb"