2x2 Button Grid layout

Try this code.

<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/tableLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TableRow
        android:id="@+id/tableRow1"
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight="1" >

        <Button
            android:id="@+id/button1"
            android:layout_width="0dp"
            android:layout_height="fill_parent"
            android:layout_weight="1" />

        <Button
            android:id="@+id/button1"
            android:layout_width="0dp"
            android:layout_height="fill_parent"
            android:layout_weight="1" />
    </TableRow>

    <TableRow
        android:id="@+id/tableRow1"
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight="1" >

        <Button
            android:id="@+id/button1"
            android:layout_width="0dp"
            android:layout_height="fill_parent"
            android:layout_weight="1" />

        <Button
            android:id="@+id/button1"
            android:layout_width="0dp"
            android:layout_height="fill_parent"
            android:layout_weight="1" />
    </TableRow>

</TableLayout>

you should use weight for buttons

I suggest you use a simple RelativeLayout without getting into the hassle of using weights (either with LinearLayout, TableLayout or a combination of both). Here is a sample layout showing how you can achieve a 2 X 2 grid that covers the entire screen using just a RelativeLayout, thereby making it more efficient and faster.

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >

<View
    android:id="@+id/centerVerticalShim"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_centerVertical="true"
    android:visibility="invisible" />

<View
    android:id="@+id/centerHorizontalShim"
    android:layout_width="0dp"
    android:layout_height="match_parent"
    android:layout_centerHorizontal="true"
    android:visibility="invisible" />

<TextView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_above="@+id/centerVerticalShim"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:layout_toLeftOf="@+id/centerHorizontalShim"
    android:background="#42A5F5"
    android:gravity="center"
    android:text="@string/one"
    android:textColor="#FFFFFF" >
</TextView>

<TextView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_above="@+id/centerVerticalShim"
    android:layout_alignParentRight="true"
    android:layout_alignParentTop="true"
    android:layout_toRightOf="@+id/centerHorizontalShim"
    android:background="#EF5350"
    android:gravity="center"
    android:text="@string/two"
    android:textColor="#FFFFFF" >
</TextView>

<TextView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentBottom="true"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/centerVerticalShim"
    android:layout_toLeftOf="@+id/centerHorizontalShim"
    android:background="#66BB6A"
    android:gravity="center"
    android:text="@string/three"
    android:textColor="#FFFFFF" >
</TextView>

<TextView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentBottom="true"
    android:layout_alignParentRight="true"
    android:layout_below="@+id/centerVerticalShim"
    android:layout_toRightOf="@+id/centerHorizontalShim"
    android:background="#5C6BC0"
    android:gravity="center"
    android:text="@string/four"
    android:textColor="#FFFFFF" >
</TextView></RelativeLayout>

The above layout results in this: