When an app has layout content that might be longer than the height of the device and that content should be vertically scrollable, then we need to use a ScrollView.

To make any content vertically scrollable, simply wrap that content in a ScrollView:

<ScrollView
 android:layout_width="match_parent"
 android:layout_height="match_parent">
 <LinearLayout
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:orientation="vertical" > 
 
 <TextView
 android:id="@+id/tv_long"
 android:layout_width="wrap_content"
 android:layout_height="match_parent"
 android:text="@string/really_long_string" >
 </TextView>
 
 <Button
 android:id="@+id/btn_act"
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:text="View" >
 </Button>
 </LinearLayout>
</ScrollView>

Note that a ScrollView can only contain a single child element so if you need multiple things to be scrollable, you need to wrap that content into a layout as shown above.

In certain situations, you want to position content beneath the end of the scrollable content area. For example for a "terms of service" where you can only accept once you've scrolled through all the content. In this case, you might need to apply the android:fillViewport property to "true". Read this post by Romain Guy for a detailed look at this use case.

Note that a TextView doesn't require a ScrollView and if you just need a scrolling TextView simply set the scrollbars property and apply the correct MovementMethod:

<TextView
 android:id="@+id/tv_long"
 android:layout_width="wrap_content"
 android:layout_height="match_parent"
 android:scrollbars = "vertical"
 android:text="@string/really_long_string" >
</TextView>

and then in the activity:

TextView tv = (TextView) findViewById(R.id.tv_long);
tv.setMovementMethod(new ScrollingMovementMethod());

Now the TextView will automatically scroll vertically.

In other cases, we want content to horizontally scroll in which case we need to use the HorizontalScrollView instead like this:

<HorizontalScrollView
 android:layout_width="match_parent"
 android:layout_height="match_parent">
 <LinearLayout
 android:layout_width="match_parent"
 android:layout_height="wrap_content"
 android:orientation="horizontal" > 
 <!-- child views in here -->
 </LinearLayout>
</HorizontalScrollView>

and now you have a horizontally scrolling view.

Adding a ScrollView within another ScrollView can be difficult. Most of the times it won’t end well. You will end up adding few workarounds. Instead, use the NestedScrollView as outlined here. A working sample can be found here as this is very useful when working with CoordinatorLayout

• http://examples.javacodegeeks.com/android/core/ui/scrollview/android-scrollview-example/
• http://www.curious-creature.org/2010/08/15/scrollviews-handy-trick/
• http://www.androidhub4you.com/2013/05/simple-scroll-view-example-in-android.html
• http://developer.android.com/reference/android/widget/ScrollView.html
• http://developer.android.com/reference/android/widget/HorizontalScrollView.html
• http://www.whitesof.com/?q=tutorials/android/android-scroll-view-tutorial