Partly missing content problem in ScrollView on an AbsoluteLayout

I have the following layout:

<AbsoluteLayout android:layout_width="fill_parent"
    android:id="@+id/absoluteLayout1" android:layout_height="wrap_content"
    xmlns:android="http://schemas.android.com/apk/res/android">
    <TextView android:layout_width="fill_parent" android:layout_x="0dip"
        android:id="@+id/textView1" android:layout_height="wrap_content"
        android:text="Hello" android:layout_y="0dip"></TextView>
    <ScrollView android:layout_x="0dip" android:layout_y="100dip"
        android:id="@+id/ScrollView01" android:layout_width="fill_parent"
        android:layout_height="fill_parent" android:scrollbars="vertical">

        <LinearLayout android:id="@+id/LinearLayout01"
            android:layout_width="fill_parent" android:layout_height="fill_parent"
            android:layout_weight="0" android:orientation="vertical"
            xmlns:android="http://schemas.android.com/apk/res/android">

        </LinearLayout>

    </ScrollView>

</AbsoluteLayout>

And a short code:

public class LayoutTest extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        LinearLayout  linerLayout=(LinearLayout)findViewById(R.id.LinearLayout01);

        for (int i=1;i<=20;i++) {
            Button b=new Button(this);
            b.setText("Button "+i);
            linerLayout.addView(b,0);
        }

    }
}

My problem is: I don't see the last two button what I generated!

I figured out this is because the ScrollView has an Y value in: android:layout_y="100dip".

The 100 pixels is exactly the same what I don't see.

If I put an empty view after the buttons with 100 pixels height:

<ScrollView android:layout_x="0dip" android:layout_y="100dip"
        android:id="@+id/ScrollView01" android:layout_width="fill_parent"
        android:layout_height="fill_parent" android:scrollbars="vertical">

        <LinearLayout android:id="@+id/LinearLayout01"
            android:layout_width="fill_parent" android:layout_height="fill_par开发者_运维百科ent"
            android:layout_weight="0" android:orientation="vertical"
            xmlns:android="http://schemas.android.com/apk/res/android">

            <TextView android:layout_width="fill_parent" android:text=""
                android:id="@+id/TextViewGap" android:layout_height="100px"
                android:background="#ff0000"></TextView>
        </LinearLayout>

    </ScrollView>

then I see every button. If I set 101 pixels for the TextView then I see a red line at bottom of the screen.

My question is: why I don't see the full content of my ScrollView when it has an Y offset on an AbsoluteLayout?

---

AbsoluteLayout is deprecated, anyway it's probably because by setting ScrollView's height to fill_parent it gets the height of the whole Layout, not considering the 100dip offset.

Consider using a RelativeLayout, it often can do in a more efficient way what other complex layouts do (like nested horizontal/vertical LinearLayouts).