Problem in android programming(beginner)?

I have problem guys, in the program i have two textview and one button. and my layout is linear layout, when I put all of them wrap content height and width they all become next to each other but when I change the text view into fill_parent, the textview takes the whole wdith and the other textview and button disappear. What is the problem??

Here is the code:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android%22

xmlns:tools="http://schemas.android.com/tools%22

android:layout_width="match_parent"

android:layout_height="match_parent"

tools:context=".MainActivity" >

<TextView

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:gravity="center"

android:text="@string/hello_world" />

<TextView

android:layout_height="wrap_content"

android:layout_width="wrap_content"

android:text="@string/menu_settings"/>

<Button

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:text="Tutorial Button"

android:textsize="25dp" />

</LinearLayout>