Visible DTMF Piano: Visualizer + ToneGenerator

Last post show a example of Visualizer for MediaPlayer, combine with the DTMF Piano using ToneGenerator, here is a Visible DTMF Piano, using Visualizer + ToneGenerator.

In this example, Visualizer is created with session 0, to make the audio output mix is visualized; permission MODIFY_AUDIO_SETTINGS is needed.



VisualizerView.java, extends View.

package com.example.androidaudiovisualizer;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;

public class VisualizerView extends View {

 private byte[] mBytes;
 private float[] mPoints;
 private Rect mRect = new Rect();
 private Paint mForePaint = new Paint();

 public VisualizerView(Context context) {
  super(context);
  init();
 }

 public VisualizerView(Context context, AttributeSet attrs) {
  super(context, attrs);
  init();
 }

 public VisualizerView(Context context, AttributeSet attrs, int defStyleAttr) {
  super(context, attrs, defStyleAttr);
  init();
 }

 private void init() {
  mBytes = null;
  mForePaint.setStrokeWidth(1f);
  mForePaint.setAntiAlias(true);
  mForePaint.setColor(Color.rgb(0, 128, 255));
 }

 public void updateVisualizer(byte[] bytes) {
  mBytes = bytes;
  invalidate();
 }

 @Override
 protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
  if (mBytes == null) {
   return;
  }
  if (mPoints == null || mPoints.length < mBytes.length * 4) {
   mPoints = new float[mBytes.length * 4];
  }
  mRect.set(0, 0, getWidth(), getHeight());
  for (int i = 0; i < mBytes.length - 1; i++) {
   mPoints[i * 4] = mRect.width() * i / (mBytes.length - 1);
   mPoints[i * 4 + 1] = mRect.height() / 2
     + ((byte) (mBytes[i] + 128)) * (mRect.height() / 2) / 128;
   mPoints[i * 4 + 2] = mRect.width() * (i + 1) / (mBytes.length - 1);
   mPoints[i * 4 + 3] = mRect.height() / 2
     + ((byte) (mBytes[i + 1] + 128)) * (mRect.height() / 2)
     / 128;
  }
  canvas.drawLines(mPoints, mForePaint);
 }

}

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.androidaudiovisualizer.MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold" />
    
    <com.example.androidaudiovisualizer.VisualizerView
        android:id="@+id/myvisualizerview"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />
    
    <GridView
        android:id="@+id/gridView"
        android:layout_width="fill_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:columnWidth="50dp"
        android:gravity="center"
        android:numColumns="3"
        android:stretchMode="columnWidth" >
    </GridView>

</LinearLayout>

MainActivity.java

package com.example.androidaudiovisualizer;

import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.GridView;
import android.media.AudioManager;
import android.media.ToneGenerator;
import android.media.audiofx.Visualizer;
import android.os.Bundle;

/*
 * needed in AndroidManifest.xml
 * android:minSdkVersion="9"
 * uses-permission of "android.permission.RECORD_AUDIO"
 * and "android.permission.MODIFY_AUDIO_SETTINGS"
 * 
 * reference: Android demo example -
 * ApiDemos > Media > AudioTx
 */

public class MainActivity extends ActionBarActivity {

 VisualizerView mVisualizerView;
 GridView DTMFPianoView;
 static final String[] numbers = new String[] { "1", "2", "3", "4", "5",
   "6", "7", "8", "9", "*", "0", "#" };

 static final int[] toneTypes = new int[] { ToneGenerator.TONE_DTMF_1,
   ToneGenerator.TONE_DTMF_2, ToneGenerator.TONE_DTMF_3,
   ToneGenerator.TONE_DTMF_4, ToneGenerator.TONE_DTMF_5,
   ToneGenerator.TONE_DTMF_6, ToneGenerator.TONE_DTMF_7,
   ToneGenerator.TONE_DTMF_8, ToneGenerator.TONE_DTMF_9,
   ToneGenerator.TONE_DTMF_S, ToneGenerator.TONE_DTMF_0, 
   ToneGenerator.TONE_DTMF_P
 };

 private Visualizer mVisualizer;

 int streamType;
 int volume;
 int durationMs;
 ToneGenerator toneGenerator;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  mVisualizerView = (VisualizerView) findViewById(R.id.myvisualizerview);

  initAudio();

  DTMFPianoView = (GridView) findViewById(R.id.gridView);
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(
          this, android.R.layout.simple_list_item_1, numbers);
        
        DTMFPianoView.setAdapter(adapter);
        
        DTMFPianoView.setOnItemClickListener(new OnItemClickListener() {

   @Override
   public void onItemClick(AdapterView<?> parent, View view,
     int position, long id) {
    toneGenerator.startTone(toneTypes[position], durationMs);
    
   }});
        
 }

 @Override
 protected void onPause() {
  super.onPause();
  if (isFinishing()) {
   mVisualizer.release();
  }
 }

 private void initAudio() {

  streamType = AudioManager.STREAM_MUSIC;
  volume = 50;
  durationMs = 500;
  toneGenerator = new ToneGenerator(streamType, volume);

  setupVisualizerFxAndUI();
  mVisualizer.setEnabled(true);

 }

 private void setupVisualizerFxAndUI() {

  // Creating a Visualizer on the output mix (audio session 0)
  // need permission MODIFY_AUDIO_SETTINGS
  mVisualizer = new Visualizer(0);

  mVisualizer.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
  mVisualizer.setDataCaptureListener(
    new Visualizer.OnDataCaptureListener() {
     public void onWaveFormDataCapture(Visualizer visualizer,
       byte[] bytes, int samplingRate) {
      mVisualizerView.updateVisualizer(bytes);
     }

     public void onFftDataCapture(Visualizer visualizer,
       byte[] bytes, int samplingRate) {
     }
    }, Visualizer.getMaxCaptureRate() / 2, true, false);

 }

}

Permission of "android.permission.RECORD_AUDIO" and "android.permission.MODIFY_AUDIO_SETTINGS" are needed in AndroidManifest.xml.

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