Android _ v1

package com.example.iptea.audio22;

import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioTrack;
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 org.w3c.dom.Text;

public class MainActivity extends AppCompatActivity {

    Thread t; //audio processing thread
    int sr = 44100; //sampling rate
    boolean isRunning = true; //audio on off

    SeekBar fSlider;
    double sliderval;
    private static TextView text_view;

    Button start;
    Button stop;

    @Override

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

    }

    public void buttonStartClick(View v) {
        //Button button = (Button) v;

    }

    public void buttonStopClick(View v) {

    }

    public void onDestroy(){
        super.onDestroy();
        isRunning = false;
        try {
            t.join();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        t = null;
    }

    public void seebBar() {
        final int progress_value;

        fSlider = (SeekBar) findViewById(R.id.frequency);
        text_view = (TextView)findViewById(R.id.textView2);
        text_view.setText("Progress: " + fSlider.getProgress() + " / " + fSlider.getMax());

        SeekBar.OnSeekBarChangeListener listener = new SeekBar.OnSeekBarChangeListener() {
            double fr2 = 440.f;
            double max_freq;
            int progress_value;
            public void onStopTrackingTouch(SeekBar seekBar) { }
            public void onStartTrackingTouch(SeekBar seekBar) { }
            public void onProgressChanged(SeekBar seekBar,
                                          int progress,
                                          boolean fromUser) {

                if(fromUser) sliderval = progress / (double)seekBar.getMax();   //pick slider value
                fr2 =  440 + 440*sliderval;
                max_freq = 440 + 440;
                text_view.setText("Progress: " + fr2 + " / " + max_freq); //fSlider.getMax()

            }
        };

        fSlider.setOnSeekBarChangeListener(listener);


        t = new Thread() {
            public void run() {
                // set process priority
                setPriority(Thread.MAX_PRIORITY);       //instantiate thread object with max priority
                // set the buffer size
                int buffsize = AudioTrack.getMinBufferSize(sr,  //setting the buffer size for output audio
                        AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT);
                // create an audiotrack object
                AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,   //instantiate audioTrack object
                        sr, AudioFormat.CHANNEL_OUT_MONO,
                        AudioFormat.ENCODING_PCM_16BIT, buffsize,
                        AudioTrack.MODE_STREAM);

                short samples[] = new short[buffsize];  //audio synthesis
                int amp = 10000;
                double twopi = 8.*Math.atan(1.);
                double fr = 440.f;
                double ph = 0.0;

                // start audio
                audioTrack.play();      //audio running

                // synthesis loop
                while(isRunning){   //synthesis loop

                    fr =  440 + 440*sliderval;

                    for(int i=0; i < buffsize; i++){
                        samples[i] = (short) (amp*Math.sin(ph));
                        ph += twopi*fr/sr;
                    }
                    audioTrack.write(samples, 0, buffsize);
                }
                audioTrack.stop();
                audioTrack.release();
            }
        };

        t.start();
    }


}