Eclipse下Android登录界面详细代码设计

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="fill_parent" android:layout_height="fill_parent"
 android:gravity="right" android:layout_gravity="right"
 android:background="@drawable/default_bg" android:orientation="vertical">
 <TableLayout android:layout_width="fill_parent"
  android:layout_height="wrap_content" android:stretchColumns="1">
  <TableRow android:gravity="center" android:layout_gravity="center">
   <ImageView android:layout_width="fill_parent" 
    android:layout_height="wrap_content" android:id="@+id/ivlogo"
    >
   </ImageView>
  </TableRow>
 </TableLayout>
 <TableLayout android:layout_width="fill_parent"
  android:layout_height="wrap_content" android:stretchColumns="1">
  <TableRow android:layout_marginTop="100dip">
   <TextView android:layout_width="wrap_content"
    android:layout_marginLeft="20dip" android:gravity="center_vertical"
    android:layout_height="wrap_content" android:id="@+id/tvaccount"
    android:text="Õʺţº" android:textSize="20sp">
   </TextView>

   <EditText android:layout_width="70px" android:layout_height="wrap_content"
    android:id="@+id/etaccount" android:layout_marginRight="20dip"
    android:maxLength="20"></EditText>
  </TableRow>
  <TableRow android:layout_marginTop="10dip">
   <TextView android:layout_width="wrap_content"
    android:layout_height="wrap_content" android:id="@+id/tvpw"