How to show/draw the spectrum frequency from line into bar shape (android)? -

i learning how make spectrum analyzer. learn tutorial , here's code

package com.example.prasetyo.spectrumanalyzer;  import android.app.activity; import android.graphics.bitmap; import android.graphics.canvas; import android.graphics.color; import android.graphics.paint; import android.media.audioformat; import android.media.audiorecord; import android.media.mediarecorder; import android.os.asynctask; import android.os.bundle; import android.util.log; import android.view.view; import android.view.view.onclicklistener; import android.widget.button; import android.widget.imageview; import ca.uol.aig.fftpack.realdoublefft;    /*public class spectrumactivity extends actionbaractivity {      @override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_spectrum);     }*/  public class spectrumactivity extends activity implements onclicklistener {      public void onclick(view v) {         if (started) {             started = false;             startstopbutton.settext("start");             recordtask.cancel(true);         } else {             started = true;             startstopbutton.settext("stop");             recordtask = new recordaudio();             recordtask.execute();         }     }      int frequency = 8000;     int channelconfiguration = audioformat.channel_in_mono;     int audioencoding = audioformat.encoding_pcm_16bit;       private realdoublefft transformer;     int blocksize = 256;     button startstopbutton;     boolean started = false;      recordaudio recordtask;     imageview imageview;     bitmap bitmap;     canvas canvas;     paint paint;        @override     public void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_spectrum);          startstopbutton = (button) this.findviewbyid(r.id.startstopbutton);         startstopbutton.setonclicklistener(this);         transformer = new realdoublefft(blocksize);         imageview = (imageview) this.findviewbyid(r.id.imageview01);         bitmap = bitmap.createbitmap(256, 100, bitmap.config.argb_8888);         canvas = new canvas(bitmap);         paint = new paint();         paint.setcolor(color.green);         imageview.setimagebitmap(bitmap);     }      /*public void onclick(view v) {         if (started) {             started = false;             startstopbutton.settext("start");             recordtask.cancel(true);         } else {             started = true;             startstopbutton.settext("stop");             recordtask = new recordaudio();             recordtask.execute();         }     }*/       private class recordaudio extends asynctask<void, double[], void> {         @override         protected void doinbackground(void... params) {               if(iscancelled()){                 return null;             }              //try {                 int buffersize = audiorecord.getminbuffersize(frequency, channelconfiguration, audioencoding);                 audiorecord audiorecord = new audiorecord(mediarecorder.audiosource.mic, frequency, channelconfiguration, audioencoding, buffersize);                 short[] buffer = new short[blocksize];                 double[] totransform = new double[blocksize];              try {                 audiorecord.startrecording();             }             catch (illegalstateexception e) {                 log.e("recording failed", e.tostring());             }                 while (started) {                     int bufferreadresult = audiorecord.read(buffer, 0, blocksize);                     (int = 0; < blocksize && < bufferreadresult; i++) {                         totransform[i] = (double) buffer[i] / 32768.0; // signed 16 bit                     }                     transformer.ft(totransform);                     publishprogress(totransform);                     //log.e("audiorecord", "recording failed");                     //return null;                 }             return null;         }           protected void onprogressupdate(double[]... totransform) {             canvas.drawcolor(color.black);             (int = 0; < totransform[0].length; i++) {                 int x;                 x = i;                 int downy = (int) (100 - (totransform[0][i] * 10));                 int upy = 100;                 canvas.drawline(x, downy, x, upy, paint);                 imageview.invalidate();             }         }          /*public void onclick(view v) {             if (started) {                 started = false;                 startstopbutton.settext("start");                 recordtask.cancel(true);             } else {                 started = true;                 startstopbutton.settext("stop");                 recordtask = new recordaudio();                 recordtask.execute();             }         }*/     } } 

spectrum show line each frequency. if i'm not mistaken, showed line appear because of drawline method. there way show frequency in other shape (bar)? need :) here's illustration here ilustration https://drive.google.com/open?id=0b3jsxxkra7plclfymddmulk5meu&authuser=0

you can replace canvas.drawline(x, downy, x, upy, paint); canvas.drawrect(x * 5, downy, x * 5 + 4, upy, paint);

canvas.drawrect