multiline_spinner_dropdown_item.xml

<CheckedTextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@android:id/text1"
    style="?android:attr/spinnerDropDownItemStyle"
    android:singleLine="false"
    android:layout_width="match_parent"
    android:layout_height="?android:attr/listPreferredItemHeight"
    android:ellipsize="marquee" />

 

this.mAdapter = ArrayAdapter.createFromResource(this, R.array.Planets,
                 R.layout.multiline_spinner_dropdown_item);