Conversor de metros para pés usando SeekBar (falta implementação do botão "Limpar")

ConversorAltura.java

package com.example.labc.conversor_altura;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.SeekBar;
import android.widget.TextView;

import java.util.Locale;

public class MainActivity extends AppCompatActivity {

    int altemCentimetros = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final TextView txtMetros = (TextView) findViewById(R.id.txtMetros);
        final TextView txtPes = (TextView) findViewById(R.id.txtPes);
        final SeekBar seekMetros = (SeekBar) findViewById(R.id.seekMetros);

        seekMetros.setMax(230);
        seekMetros.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {

            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                altemCentimetros = progress;
                String texto = formataValorComDoisDigitos(progress/100.00);
                texto += ".m";
                txtMetros.setText(texto);
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {
                txtPes.setText("pé(s) : toque em 'Converter'");
            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {}
        });

        final Button btnConvert = (Button) findViewById(R.id.btnConvert);

        btnConvert.setOnClickListener(new Button.OnClickListener(){

            @Override
            public void onClick(View v) {
                double altEmPes = altemCentimetros / 30.48;
                String texto = formataValorComDoisDigitos(altEmPes);
                texto += "pé(s)";
                txtPes.setText(texto);
            }
        });

    }

    private String formataValorComDoisDigitos(double valor) {
        return String.format(Locale.ENGLISH, "%.2f", valor);
    }
}

ConversorAltura.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="86dp"
        android:layout_height="35dp"
        android:layout_alignParentStart="true"
        android:layout_alignParentTop="true"
        android:layout_marginStart="35dp"
        android:layout_marginTop="76dp"
        android:text="Altura:"
        android:textStyle="bold"
        tools:textColor="@color/colorPrimaryDark"
        tools:textSize="18sp" />

    <SeekBar
        android:id="@+id/seekMetros"
        android:layout_width="278dp"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_below="@+id/textView"
        android:layout_marginEnd="41dp" />

    <TextView
        android:id="@+id/txtPes"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="0,0 (pés)"
        android:textStyle="italic"
        tools:textSize="18sp" />

    <TextView
        android:id="@+id/txtMetros"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="140dp"
        android:text="0,0m"
        tools:textSize="18sp" />

    <Button
        android:id="@+id/btnLimpar"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="176dp"
        android:text="Limpar" />

    <Button
        android:id="@+id/btnConvert"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="175dp"
        android:text="Converter" />

</RelativeLayout>