SI Calc Code 2

package com.codeherenow.sicalculator;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.SeekBar;

public class SICalculatorActivity extends Activity
        implements SeekBar.OnSeekBarChangeListener, View.OnClickListener{
    private int years;
    private TextView YT;
    public EditText pvalue;
    public EditText ivalue;
    private double mPvalue = 0;
    private double mIvalue = 0;
    private TextView fTextView = (TextView) findViewById(R.id.finalText);

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.sicalculator);
        EditText principal = (EditText) findViewById(R.id.PA_field);
        EditText interest = (EditText) findViewById(R.id.IR_field);
        pvalue = (EditText) findViewById(R.id.PA_field);
        ivalue  = (EditText) findViewById(R.id.IR_field);
        SeekBar bar = (SeekBar) findViewById(R.id.seekBar);
        YT = (TextView) findViewById(R.id.Years);
        bar.setOnSeekBarChangeListener(this);
        pvalue = (EditText) principal.getText();
        ivalue = (EditText) interest.getText();
        String s = principal.getText().toString();
        mPvalue = Double.parseDouble(s);
        String s2 = interest.getText().toString();
        mIvalue = Double.parseDouble(s2);


    }
        @Override
        public void onProgressChanged (SeekBar seekBar,int i, boolean b){
            years = i;
            YT.setText(years + " Year(s)");

        }

        @Override
        public void onStartTrackingTouch (SeekBar seekBar){

        }

        @Override
        public void onStopTrackingTouch (SeekBar seekBar){

        }

    @Override
    public void onClick(View view) {

        double finValue = mPvalue * (mIvalue/100) * years;
        fTextView.setText("The interest for " + pvalue + "at a rate of " + ivalue + "for " + years + "year(s) is " + finValue);
    }
}