MainActivity.java [v13+] without Circular Seekbar

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.MotionEvent;
import android.view.View;
import android.widget.ImageView;
import android.widget.SeekBar;

import com.hanks.htextview.base.HTextView;
import com.skyfishjy.library.RippleBackground;

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;
    public double fr = 440.f;
    public int counter = 0;
    public double max_frequency = 0;
    @Override

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

        final RippleBackground rippleBackground=(RippleBackground)findViewById(R.id.contents);
        final HTextView animText = (HTextView)findViewById(R.id.animatedText);

        ImageView kulak=(ImageView)findViewById(R.id.centerImage);
        kulak.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                String both;

                switch (event.getAction()) {
                    case MotionEvent.ACTION_DOWN:

                        isRunning = true;
                        fSlider = (SeekBar) findViewById(R.id.frequency);

                        rippleBackground.startRippleAnimation();
                        t = new Thread() {
                            public void run() {
                                int buffsize = AudioTrack.getMinBufferSize(sr,
                                        AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT);
                                AudioTrack audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC,
                                        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 ph = 0.0;
                                audioTrack.play();      //audio running

                                while(isRunning){   //synthesis loop

                                    sliderval = counter*0.5 / fSlider.getMax();
                                    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);

                                    runOnUiThread(new Runnable() {
                                        @Override
                                        public void run() {
                                            if (( counter % 10 ) == 0) {
                                                fSlider.setProgress(counter/89);  // counter/100
                                                counter = counter + 100;
                                            }
                                        }
                                    });

                                    if (fr > 20000) {
                                        counter = 0;
                                    }
                                }
                                counter = 0;

                                audioTrack.stop();
                                audioTrack.release();
                            }
                        };

                        t.start();
                        return true;

                    case MotionEvent.ACTION_UP:

                        if (fr > max_frequency) {
                            max_frequency = fr;
                            both = "You can hear up to: " + String.valueOf(max_frequency) + " Hz";
                            animText.animateText(both);
                        }
                        isRunning = false;
                        counter = 0;
                        t = null;
                        rippleBackground.stopRippleAnimation();

                        return true;
                }

                return false;
            }
        });
    }

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