Apps Making a simple timer

[anta40]

This is my first android app: a simple timer.

Screenshots:
http://i47.tinypic.com/zj8chu.jpg
http://i47.tinypic.com/fthcli.jpg

At the moment, I'm working on these 2 problems.
First, there's a textview under the clock, but it is not displayed (XML problem?).
Second, the timer doesn't work. Let's say 3 seconds is chosen as interval, than a text is supposed to be shown under the clock for each 3 seconds. But it doesn't.

This is my code, so far.

Reminder.java

package com.anta40.reminder;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Timer;
import java.util.TimerTask;

import android.app.Activity;
import android.os.Bundle;
import android.widget.RadioGroup;
import android.widget.TabHost;
import android.widget.TextView;
import android.widget.RadioGroup.OnCheckedChangeListener;
import android.widget.TabHost.TabSpec;

public class Reminder extends Activity{
	
	public final int TIMER_DELAY = 1000;
	public final int TIMER_ONE_MINUTE = 60000; 
	public final int TIMER_ONE_SECOND = 1000;
	Timer timer;
	TimerTask task;
	TextView tv;
	
	@Override
	public void onCreate(Bundle icicle) {

		super.onCreate(icicle);
		setContentView(R.layout.main);
		timer = new Timer();

		task = new TimerTask() {
			
			@Override
			public void run() {
				tv = (TextView) findViewById(R.id.textview1);
				tv.setText("BOOM!!!!");
				tv.setVisibility(TextView.VISIBLE);
				try {
					this.wait(TIMER_DELAY);
				}
				catch (InterruptedException e){
					
				}
				tv.setVisibility(TextView.INVISIBLE);
			}
			
		};
		
		TabHost tabs=(TabHost)findViewById(R.id.tabhost);

		tabs.setup();

		TabSpec spec = tabs.newTabSpec("tag1");

		spec.setContent(R.id.tab1);
		spec.setIndicator("Clock");
		tabs.addTab(spec);
		
		spec=tabs.newTabSpec("tag2");
		spec.setContent(R.id.tab2);
		spec.setIndicator("Settings");
		tabs.addTab(spec);
		
		tabs.setCurrentTab(0);
		
		RadioGroup rgroup = (RadioGroup) findViewById(R.id.rgroup);
		rgroup.setOnCheckedChangeListener(new OnCheckedChangeListener() {
			
			@Override
			public void onCheckedChanged(RadioGroup group, int checkedId) {
				if (checkedId == R.id.om){
					timer.schedule(task, TIMER_DELAY, 3*TIMER_ONE_SECOND);
				}
				else if (checkedId == R.id.twm){
					timer.schedule(task, TIMER_DELAY, 6*TIMER_ONE_SECOND);
				}
				else if (checkedId == R.id.thm){
					timer.schedule(task, TIMER_DELAY, 9*TIMER_ONE_SECOND);
				}
			}
		});

	}
}

main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
	android:orientation="vertical"
	android:layout_width="fill_parent"
	android:layout_height="fill_parent">
	<TabHost android:id="@+id/tabhost"
		android:layout_width="fill_parent"
		android:layout_height="fill_parent">
		<TabWidget android:id="@android:id/tabs"
			android:layout_width="fill_parent"
			android:layout_height="wrap_content"
		/>
		<FrameLayout android:id="@android:id/tabcontent"
			android:layout_width="fill_parent"
			android:layout_height="fill_parent"
			android:paddingTop="62px">
			<LinearLayout android:id="@+id/tab1"
				android:layout_width="fill_parent" 
				android:layout_height="fill_parent"
				android:layout_centerHorizontal="true">
				
				<AnalogClock android:id="@+id/clock"
				android:layout_width="fill_parent" 
				android:layout_height="fill_parent"
				android:layout_centerHorizontal="true"
				/>
				
				<TextView android:id="@+id/textview1"
				android:layout_width="fill_parent" 
				android:layout_height="wrap_content"
				android:text="Lalalala....."
				/>
			</LinearLayout>
			
			<LinearLayout android:id="@+id/tab2"
				android:orientation="vertical"
				android:layout_width="fill_parent" 
				android:layout_height="fill_parent"
				android:layout_centerHorizontal="true">
				
				<TextView android:id="@+id/textview2"
					android:layout_width="fill_parent"
				    android:layout_height="wrap_content"
				    android:text="Interval: "/>
				
				<RadioGroup android:id="@+id/rgroup"
				    android:orientation="vertical"
				    android:layout_width="fill_parent"
				    android:layout_height="wrap_content"
				    android:padding="5px">
				    <RadioButton
				      android:id="@+id/om"
				      android:text="3 seconds" />
				    <RadioButton
				      android:id="@+id/twm"
				      android:text="6 seconds" />
				    <RadioButton
				      android:id="@+id/thm"
				      android:text="9 seconds" />
				 </RadioGroup>
  			</LinearLayout>
		</FrameLayout>
	</TabHost>
</LinearLayout>