How to group a 3×3 grid of radio buttons?

Actually it’s not that hard if you subclass TableLayout like in this example

/**
 * 
 */
package com.codtech.android.view;

import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.RadioButton;
import android.widget.TableLayout;
import android.widget.TableRow;

/**
 * @author diego
 *
 */
public class ToggleButtonGroupTableLayout extends TableLayout  implements OnClickListener {

    private static final String TAG = "ToggleButtonGroupTableLayout";
    private RadioButton activeRadioButton;

    /** 
     * @param context
     */
    public ToggleButtonGroupTableLayout(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
    }

    /**
     * @param context
     * @param attrs
     */
    public ToggleButtonGroupTableLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onClick(View v) {
        final RadioButton rb = (RadioButton) v;
        if ( activeRadioButton != null ) {
            activeRadioButton.setChecked(false);
        }
        rb.setChecked(true);
        activeRadioButton = rb;
    }

    /* (non-Javadoc)
     * @see android.widget.TableLayout#addView(android.view.View, int, android.view.ViewGroup.LayoutParams)
     */
    @Override
    public void addView(View child, int index,
            android.view.ViewGroup.LayoutParams params) {
        super.addView(child, index, params);
        setChildrenOnClickListener((TableRow)child);
    }


    /* (non-Javadoc)
     * @see android.widget.TableLayout#addView(android.view.View, android.view.ViewGroup.LayoutParams)
     */
    @Override
    public void addView(View child, android.view.ViewGroup.LayoutParams params) {
        super.addView(child, params);
        setChildrenOnClickListener((TableRow)child);
    }


    private void setChildrenOnClickListener(TableRow tr) {
        final int c = tr.getChildCount();
        for (int i=0; i < c; i++) {
            final View v = tr.getChildAt(i);
            if ( v instanceof RadioButton ) {
                v.setOnClickListener(this);
            }
        }
    }

    public int getCheckedRadioButtonId() {
        if ( activeRadioButton != null ) {
            return activeRadioButton.getId();
        }

        return -1;
    }
}

and create a layout like this (of course you need to clean it up but you got the idea)

<?xml version="1.0" encoding="utf-8"?>
<com.codtech.android.view.ToggleButtonGroupTableLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content" android:layout_height="wrap_content"
    android:id="@+id/radGroup1">
    <TableRow>
            <RadioButton android:id="@+id/rad1" android:text="Button1"
                android:layout_width="105px" android:layout_height="wrap_content"
                android:textSize="13px" />
            <RadioButton android:id="@+id/rad2" android:text="Button2"
                android:layout_width="105px" android:textSize="13px"
                android:layout_height="wrap_content" />
            <RadioButton android:id="@+id/rad3" android:text="Button3"
                android:layout_width="105px" android:textSize="13px"
                android:layout_height="wrap_content" />
    </TableRow>
    <TableRow>
            <RadioButton android:id="@+id/rad1" android:text="Button1"
                android:layout_width="105px" android:layout_height="wrap_content"
                android:textSize="13px" />
            <RadioButton android:id="@+id/rad2" android:text="Button2"
                android:layout_width="105px" android:textSize="13px"
                android:layout_height="wrap_content" />
            <RadioButton android:id="@+id/rad3" android:text="Button3"
                android:layout_width="105px" android:textSize="13px"
                android:layout_height="wrap_content" />
    </TableRow>
    <TableRow>
            <RadioButton android:id="@+id/rad1" android:text="Button1"
                android:layout_width="105px" android:layout_height="wrap_content"
                android:textSize="13px" />
            <RadioButton android:id="@+id/rad2" android:text="Button2"
                android:layout_width="105px" android:textSize="13px"
                android:layout_height="wrap_content" />
            <RadioButton android:id="@+id/rad3" android:text="Button3"
                android:layout_width="105px" android:textSize="13px"
                android:layout_height="wrap_content" />
    </TableRow>
</com.codtech.android.view.ToggleButtonGroupTableLayout>