How to add string at the bottom of a ScrollView

<ScrollView 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:fillViewport="true">

    <LinearLayout
        android:id="@+id/lnContainer"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">

        <!-- your button declaration -->

    </LinearLayout>
</ScrollView>

private int position=0;
final int[] sentences = new int[]{
    R.String.sentence1, 
    R.String.sentence1, 
    R.String.sentence2, 
    R.String.sentence3, 
    R.String.sentence4
};

//inside onCreate() method
yourButton.setOnClickListener(new View.OnClickListener(){
     public void onClick(View view){
         TextView textView = new TextView(YourActivityClass.this);
         textView.setText(sentences[position++]);
         ((LinearLayout)findViewById(R.id.lnContainer)).addView(textView);
     }
});