Wrap your EditText
in a ScrollView
.
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<EditText
android:id="@+id/text_editor"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="start|top"
android:inputType="textLongMessage|textCapSentences|textMultiLine"
android:textAlignment="gravity" />
</ScrollView>