try this, turn on audio record permission
package com.aiti.vumeter;
//vumeter
//May 21 2010 Bob Gardner at aol.com
import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.media.AudioFormat;
import android.media.AudioRecord;
import android.os.Bundle;
import android.os.SystemClock;
import android.util.DisplayMetrics;
import android.view.View;
import android.widget.TextView;
public class vumeter extends Activity {
public AudioRecord audioRecord;
public VuView vuview;
public Timer timer;
public int channelConfiguration =
AudioFormat.CHANNEL_CONFIGURATION_MONO;
public int audioEncoding = AudioFormat.ENCODING_PCM_16BIT;
public int mSamplesRead; //how many samples read
public int buffersizebytes;
public int buflen;
public int scrwidth;
public int scrheight;
public int cursamprate;
public final int SAMPPERSEC = 48000; //samp per sec 8000, 11025,
22050 44100 or 48000
public float vin; //input volts
public float iavg; //avg of input volts
public float ipk; //peak input volts
public float isum; //sum of ans of input volts
public float idbavg; //db below 0 of avg input volts
public float idbpk;
public float pixperdb;
public float pixperdiv;
public final float rangedb=60.0f;
public final float dbperdiv=3.0f;
public final float barwid=30f;
public float scrbot;
public long t1,t2,dt, t3,t4,dt2;
public short[] buffer; //+-32767
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
// setContentView(R.layout.main);
DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
scrwidth=metrics.widthPixels; //
scrheight=metrics.heightPixels; //
scrbot=scrheight-100; //480-100->380
pixperdb=scrbot/rangedb; //380/60->5
pixperdiv=dbperdiv*pixperdb; //3*5->15
buffersizebytes =
AudioRecord.getMinBufferSize(SAMPPERSEC,channelConfiguration,audioEncoding); //
4096 on ion
buffer = new short[buffersizebytes]; //4096
buflen=buffersizebytes/2; //2048
audioRecord = new
AudioRecord(android.media.MediaRecorder.AudioSource.MIC,SAMPPERSEC,
channelConfiguration, audioEncoding,
buffersizebytes); //constructor
cursamprate=audioRecord.getSampleRate();
vuview = new VuView(this);
setContentView(vuview);
timer = new Timer();
timer.schedule(new TimerTask(){
@Override
public void run(){
TimerMethod();
}
}, 0, 200); //every 200 ms
// trigger(); //grab samples and calc db
}//oncreate
private void TimerMethod(){
//This method is called directly by the timer
//and runs in the same thread as the timer.
//We call the method that will work with the UI
//through the runOnUiThread method.
this.runOnUiThread(Timer_Tick);
}
private Runnable Timer_Tick = new Runnable(){
public void run() {
//This method runs in the same thread as the UI.
//Do something to the UI thread here
trigger();
}
};
//--------------------------------------
public void acquire(){
try {
audioRecord.startRecording(); //48khz
} catch (Throwable t) {
// Log.e("AudioRecord", "startrecording Failed");
}
// SystemClock.sleep(50L); //one period of 20 hz
mSamplesRead = audioRecord.read(buffer, 0, buflen);
try{
audioRecord.stop();
} catch (Throwable t) {
// Log.e("AudioRecord", "stoprecording Failed");
}
}
//-----------------------
public void avg(){
int i;
float ftmp;
ipk=0f;
isum=0f;
for(i=0; i < buflen; i++){ //2048 samples
vin=(float)buffer[i]; //get a sample
ftmp=Math.abs(vin); //abs of input sample
isum += ftmp; //sum of input samples
if(ftmp > ipk) ipk=ftmp; //remember input peak
}
iavg=isum/buflen; //avg of input
samples
idbavg= (float)(20.0*Math.log10(iavg/32767.0)); //db below clip
of
input signal
idbpk= (float)(20.0*Math.log10(ipk/32767.0)); //db of input
signal
}//avg
//--------------------------------
public void trigger(){
t1=System.currentTimeMillis();
acquire(); //grab buffer full of samples
avg(); //calc avg and db
// dump();
vuview.invalidate(); //tell os to call ondraw
t2=System.currentTimeMillis();
dt=t2-t1;
t1=t2;
}//trigger
//--------------------------------------
void dump(){
TextView tv = new TextView(this);
setContentView(tv);
tv.setTextColor(Color.WHITE);
tv.setText("buffersizebytes "+buffersizebytes+"\n");
for (int i = 0; i < buflen; i++){
tv.append(" "+buffer[i]);
}
}//dump
//-------lifecycle callbacks-------------------
@Override
public void onResume(){
super.onResume();
trigger();
}//onresume
@Override
public void onPause(){
super.onPause();
audioRecord.stop();
}//onpause
@Override
public void onStop(){
super.onStop();
audioRecord.release();
}//onstop
// @Override
// public boolean onTouchEvent(MotionEvent motionevent){
// if(motionevent.getAction()==MotionEvent.ACTION_DOWN){
// trigger(); //acquire buffer full of samples
// }
// return true;
// }
//--------------------------------------
private class VuView extends View {
public VuView(Context context) {
super(context);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
t3=System.currentTimeMillis();
graticule(canvas);
drawvu(canvas);
t4=System.currentTimeMillis();
dt2=t4-t3;
t3=t4;
}//ondraw
//------------------------------------------------
public void graticule(Canvas canvas){ //draw graticule
int i;
float TL=7;
Paint paint = new Paint();
paint.setColor(Color.BLACK);
canvas.drawPaint(paint); //clear screen
paint.setColor(Color.GRAY);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(1);
canvas.drawLine(0f,0f,0f,scrbot, paint); //y axis
(vertical)
for(i=0; i < (int)scrbot; i++){
if((i % (int)pixperdiv)==0){
canvas.drawLine(0,i,TL,i, paint); //y
axis tics (horizontal)
}
}
}//graticule
//-----------------------------------------
public void drawvu(Canvas canvas){ //draw vu
float x;
float ftmp;
Paint paint = new Paint();
paint.setColor(Color.GREEN);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(1);
x=20f; //left side of vu
ftmp=Math.abs(idbpk)*pixperdb; //abs of db, cvt to pix
if(ftmp > scrbot) ftmp=scrbot; //clip at bottom
canvas.drawLine(x, ftmp, x+barwid, ftmp, paint); //db
peak bar
paint.setStyle(Paint.Style.FILL);
canvas.drawRect(x,(float)Math.abs(idbavg)*pixperdb,
x+barwid,
scrbot, paint); //input db avg
paint.setColor(Color.WHITE);
paint.setTextSize(15);
canvas.drawText("ms " + dt, 100, 20, paint); //
canvas.drawText("ms " + dt2, 100, 40, paint); //
canvas.drawText("db/div " + dbperdiv, 100, 60, paint);
canvas.drawText("range " + rangedb, 100, 80, paint);
canvas.drawText("avg " + idbavg, 100, 100, paint);
// canvas.drawText("ht " + scrheight, 100, 120, paint);
// canvas.drawText("sr " + cursamprate,100,120, paint);
}//drawvus
}//graphview
}//activity
//-----------------------eof-----------------------
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