Hello guys,

I need to find out how to generate beep, with a specified frequency and duration (like the Beep function in C++: Beep(freq, duration)).
These beeps will have to be played in my application, under some circumstances.

Actually I found no solution except creating mp3 files and using them in SoundPool, which is not what I want.

There's a Tone generator class which exists but it cannot generate custom sounds.

If you have any idea, I will be happy to read it!

Regards!

I don't think you can make beeps like in c as c uses the system speaker, which doesn't go over sound card.

Any solution to this issue ?
I also have the same question about it.

You can use the sine function in the java math library to produce an array of short containing the beep, then play the beep using AudioTrack

Does anyone have an example of this?

I'm really interested in this but can't find anything.

Brandon

package com.aiti.computedbeep;
//play buffer full of calculated samples using audiotrack

import android.app.Activity;
import android.graphics.Color;
import android.media.AudioFormat;
import android.media.AudioManager;
import android.media.AudioTrack;
import android.os.Bundle;
import android.os.SystemClock;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.GestureDetector.OnGestureListener;
import android.widget.TextView;

public class computedbeep extends Activity implements OnGestureListener{
public AudioTrack at;
public TextView tv;
public GestureDetector gd;
public int minbufsizbytes;
public int bufsizbytes;
public int bufsizsamps;
public final int samprate = 8000;
public short[] buffer=null;
public final float f=2000.0f; //beep freq
public final float MAXVOL=(float)1.0;
public final float MINVOL=(float)0.01;
public float vol=MAXVOL;
public final int LOOPON= -1;
public final int LOOPOFF=0;
public int tmp;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// setContentView(R.layout.main);
gd=new GestureDetector(this);

tv = new TextView(this);
setContentView(tv);
tv.setTextColor(Color.WHITE);
// tv.setText("in oncreate\n"); //gets to here

minbufsizbytes = AudioTrack.getMinBufferSize(samprate,AudioFormat.CHANNEL_CONFIGURATION_MONO,
AudioFormat.ENCODING_PCM_16BIT); //870 at 8000, 4800 at 44100
bufsizbytes=minbufsizbytes; //
tv.setText("minbufsizebytes "+minbufsizbytes+"\n"); //gets to here
bufsizsamps=bufsizbytes/2;
buffer = new short[bufsizsamps];
fillbuf();
// dumpbuf();
// swapbuf();
try{
at = new AudioTrack(AudioManager.STREAM_MUSIC,samprate,
AudioFormat.CHANNEL_CONFIGURATION_MONO,
AudioFormat.ENCODING_PCM_16BIT,bufsizbytes,AudioTrack.MODE_STATIC);
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
tv.append("create audiotracksnafu "+e+"\n"); //gets to here
e.printStackTrace();
}
at.setStereoVolume(1.0f,1.0f);
tmp=at.write(buffer, 0, bufsizsamps);
}//oncreate

void playit(){
tv.append("in playit!\n"); //
at.stop();
// at.setPlaybackHeadPosition(0);
at.reloadStaticData();
at.play();
// SystemClock.sleep(1000L);
// at.stop();
}

void fillbuf(){
double omega,t;
double dt=1.0/samprate; //sec per samp

t=0.0;
omega=(float)(2.0*Math.PI*f);
for(int i=0; i < bufsizsamps; i++){
buffer[i]=(short)(32000.0*Math.sin(omega*t));
t+=dt;
}
}

/*
void swapbuf(){
short i,in,out;
byte inh,inl;

for(i=0; i < bufsizsamps; i++){
in=buffer[i];
inh=(byte) (in >> ;
inl=(byte) (in & 0xff);
out=(short) (inl*256+inh);
buffer[i]=out;
}
}

void dumpbuf(){
short i;

for(i=0; i < 256; i++){
tv.append(" "+ buffer[i]);
}
}
*/

//----------lifecycle callbacks----------------
@Override
public void onPause(){
super.onPause();
at.pause();
tv.append("onpause!\n"); //gets to here
}

@Override
public void onResume(){
super.onResume();
tv.append("onresume!\n"); //gets to here
// playit();
}

@Override
public void onStop(){
super.onStop();
at.stop();
tv.append("onstop!\n"); //gets to here
}

// @Override
// public void onDestroy(){
// super.onDestroy();
// }

//------------gesture callbacks--------------------
@Override
public boolean onTouchEvent(MotionEvent e){
if(e.getAction()==MotionEvent.ACTION_DOWN){
tv.append("in ontouch!\n"); //gets to here
playit();
}
return true;
}

@Override
public boolean onDown(MotionEvent arg0) {
// TODO Auto-generated method stub
return false;
}

@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
float velocityY) {
// TODO Auto-generated method stub
return false;
}

@Override
public void onLongPress(MotionEvent e) {
// TODO Auto-generated method stub
}

@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
float distanceY) {
// TODO Auto-generated method stub
return false;
}

@Override
public void onShowPress(MotionEvent e) {
// TODO Auto-generated method stub
}

@Override
public boolean onSingleTapUp(MotionEvent e) {
// TODO Auto-generated method stub
return false;
}
}//activity
//-----------------------------eof-------------------------------