Android - How to change default SeekBar thickness?

You have to change progressDrawable and thumb of SeekBar to adjust it's thickness :

<SeekBar    android:id="@+id/seekBar"    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:layout_below="@id/indSeekBar"    android:layout_marginTop="48dp"    android:progressDrawable="@drawable/seek_bar"    android:thumb="@drawable/seek_thumb"    />

Add in drawable folder seek_bar.xml :

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">    <item android:id="@android:id/background">        <shape            android:shape="line">            <stroke                android:color="@color/seek_bar_background"                android:width="@dimen/seek_bar_thickness"/>        </shape>    </item>    <item android:id="@android:id/secondaryProgress">        <clip>            <shape                android:shape="line">                <stroke                    android:color="@color/seek_bar_secondary_progress"                    android:width="@dimen/seek_bar_thickness"/>            </shape>        </clip>    </item>    <item android:id="@android:id/progress">        <clip>            <shape                android:shape="line">                <stroke                    android:color="@color/seek_bar_progress"                    android:width="@dimen/seek_bar_thickness"/>            </shape>        </clip>    </item></layer-list>

seek_thumb.xml :

<shape xmlns:android="http://schemas.android.com/apk/res/android"    android:shape="oval">    <size        android:height="@dimen/seek_bar_thumb_size"        android:width="@dimen/seek_bar_thumb_size"        />    <solid android:color="@color/seek_bar_progress"/></shape>

Add to dimension resources (change this to adjust thickness) :

<dimen name="seek_bar_thickness">4dp</dimen><dimen name="seek_bar_thumb_size">20dp</dimen>

Add color resources :

<color name="seek_bar_background">#ababab</color><color name="seek_bar_progress">#ffb600</color><color name="seek_bar_secondary_progress">#3399CC</color>

You should do like this:

<SeekBar    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:layout_marginTop="20dp"    android:thumb="@drawable/seek"    android:progressDrawable="@drawable/seek_style"    />

The thumb is the circle which can be dragged, and the progressDrasable is the style of progress.

seek_style.xml:

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">    <item android:id="@android:id/background">        <shape>            <corners android:radius="5dip" />            <gradient                android:startColor="#ff9d9e9d"                android:centerColor="#ff5a5d5a"                android:centerY="0.75"                android:endColor="#ff747674"                android:angle="270"                />        </shape>    </item>    <item android:id="@android:id/secondaryProgress">        <clip>            <shape>                <corners android:radius="5dip" />                <gradient                    android:startColor="#80ffd300"                    android:centerColor="#80ffb600"                    android:centerY="0.75"                    android:endColor="#a0ffcb00"                    android:angle="270"                    />            </shape>        </clip>    </item>    <item android:id="@android:id/progress">        <clip>            <shape>                <corners android:radius="5dip" />                <gradient                    android:startColor="#ff0099CC"                    android:centerColor="#ff3399CC"                    android:centerY="0.75"                    android:endColor="#ff6699CC"                    android:angle="270"                    />            </shape>        </clip>    </item></layer-list>

seek.xml:

<shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval">    <size        android:width="20dp"        android:height="20dp"        />    <solid android:color="#60f0"/></shape>

You can use the Slider provided by the Material Components Library.

Use the app:trackHeight="xxdp" (the default value is 4dp) to change the height of the track bar.

    <com.google.android.material.slider.Slider        app:trackHeight="12dp"        .../>

If you want to change also the thumb radius you can use the app:thumbRadius attribute:

        <com.google.android.material.slider.Slider            app:trackHeight="12dp"            app:thumbRadius="16dp"            ../>           

It requires the version 1.2.0 of the library.