Android ViewPager with bottom dots

No need for that much code.

You can do all this stuff without coding so much by using only viewpager with tablayout.

Your main Layout:

<RelativeLayout
   xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:app="http://schemas.android.com/apk/res-auto"
   android:layout_width="match_parent"
   android:layout_height="wrap_content">

   <android.support.v4.view.ViewPager
       android:id="@+id/pager"
       android:layout_width="match_parent"
       android:layout_height="match_parent">

   </android.support.v4.view.ViewPager>
   <android.support.design.widget.TabLayout
       android:id="@+id/tabDots"
       android:layout_alignParentBottom="true"
       android:layout_width="match_parent"
       android:layout_height="wrap_content"
       app:tabBackground="@drawable/tab_selector"
       app:tabGravity="center"
       app:tabIndicatorHeight="0dp"/>
</RelativeLayout>

Hook up your UI elements inactivity or fragment as follows:

Java Code:

mImageViewPager = (ViewPager) findViewById(R.id.pager);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabDots);
tabLayout.setupWithViewPager(mImageViewPager, true);

That's it, you are good to go.

You will need to create the following xml resource file in the drawable folder.

tab_indicator_selected.xml

<?xml version="1.0" encoding="utf-8"?>
<shape
    android:innerRadius="0dp"
    android:shape="ring"
    android:thickness="4dp"
    android:useLevel="false"
    xmlns:android="http://schemas.android.com/apk/res/android">
    <solid android:color="@color/colorAccent"/>
</shape>

tab_indicator_default.xml

<?xml version="1.0" encoding="utf-8"?>
    <shape xmlns:android="http://schemas.android.com/apk/res/android"
            android:innerRadius="0dp"
            android:shape="oval"
            android:thickness="2dp"
            android:useLevel="false">
            <solid android:color="@android:color/darker_gray"/>
    </shape>

tab_selector.xml

 <?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:drawable="@drawable/tab_indicator_selected"
          android:state_selected="true"/>

    <item android:drawable="@drawable/tab_indicator_default"/>
</selector>

Feeling as lazy as I am? Well, all the above code is converted into a library! Usage Add the following in your gradle: implementation 'com.chabbal:slidingdotsplash:1.0.2' Add the following to your Activity or Fragment layout.

<com.chabbal.slidingdotsplash.SlidingSplashView
        android:id="@+id/splash"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:imageResources="@array/img_id_arr"/>

Create an integer array in strings.xml e.g.

<integer-array name="img_id_arr">
   <item>@drawable/img1</item>
   <item>@drawable/img2</item>
   <item>@drawable/img3</item>
   <item>@drawable/img4</item>
</integer-array>

Done! Extra in order to listen page changes use addOnPageChangeListener(listener); Github link.

The solution provided by @Junaid can be simplified. Instead of creating a selector (tab_selector.xml) you can simply set the drawables on the TabLayout directly.

<com.google.android.material.tabs.TabLayout
        android:id="@+id/tabLayout"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        app:tabBackground="@drawable/tab_indicator_default"
        app:tabIndicator="@drawable/tab_indicator_selected"
        app:tabIndicatorColor="<youColor>"
        app:tabIndicatorGravity="center"
        app:tabIndicatorHeight="8dp" />

app:tabIndicatorHeight is set to the same value as in tab_indicator_selected.xml. Following this approach you keep the default animation of the TabLayout. Programmatically, you have to set the tab as selected:

object : ViewPager2.OnPageChangeCallback() {
    override fun onPageSelected(position: Int) {
        val tab = binding.tabLayout.getTabAt(position)
        binding.tabLayout.selectTab(tab, true)
    }
}

Please note that I used ViewPager2. There should be equivalent method using ViewPager.

If anyone wants to build a viewPager with thumbnails as indicators, using this library could be an option: ThumbIndicator for viewPager that works also with image links as resources.