android音乐频谱解析

 博客转载自：http://blog.csdn.net/com6339663/article/details/42681103

 package com.example.Code_Test;

 import android.content.Context;
 import android.graphics.Canvas;
 import android.graphics.Color;
 import android.graphics.Paint;
 import android.graphics.Paint.Cap;
 import android.graphics.Paint.Join;
 import android.media.audiofx.Visualizer;
 import android.util.Log;
 import android.view.View;

 public class VisualizerView extends View implements Visualizer.OnDataCaptureListener {

     private static final int DN_W = 470;//view宽度与单个音频块占比 - 正常480 需微调
     private static final int DN_H = 360;//view高度与单个音频块占比
     private static final int DN_SL = 15;//单个音频块宽度
     private static final int DN_SW = 5;//单个音频块高度

     private int hgap = 0;
     private int vgap = 0;
     private int levelStep = 0;
     private float strokeWidth = 0;
     private float strokeLength = 0;

     protected final static int MAX_LEVEL = 30;//音量柱·音频块 - 最大个数

     protected final static int CYLINDER_NUM = 26;//音量柱 - 最大个数

     protected Visualizer mVisualizer = null;//频谱器

     protected Paint mPaint = null;//画笔

     protected byte[] mData = new byte[CYLINDER_NUM];//音量柱 数组

     boolean mDataEn = true;

     //构造函数初始化画笔
     public VisualizerView(Context context) {
         super(context);

         mPaint = new Paint();//初始化画笔工具
         mPaint.setAntiAlias(true);//抗锯齿
         mPaint.setColor(Color.WHITE);//画笔颜色

         mPaint.setStrokeJoin(Join.ROUND); //频块圆角
         mPaint.setStrokeCap(Cap.ROUND); //频块圆角
     }

     //执行 Layout 操作
     @Override
     protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
         super.onLayout(changed, left, top, right, bottom);

         float w, h, xr, yr;

         w = right - left;
         h = bottom - top;
         xr = w / (float) DN_W;
         yr = h / (float) DN_H;

         strokeWidth = DN_SW * yr;
         strokeLength = DN_SL * xr;
         hgap = (int) ((w - strokeLength * CYLINDER_NUM) / (CYLINDER_NUM + 1));
         vgap = (int) (h / (MAX_LEVEL + 2));//频谱块高度

         mPaint.setStrokeWidth(strokeWidth); //设置频谱块宽度
     }

     //绘制频谱块和倒影
     protected void drawCylinder(Canvas canvas, float x, byte value) {
         if (value == 0) {value = 1;}//最少有一个频谱块
         for (int i = 0; i < value; i++) { //每个能量柱绘制value个能量块
             float y = (getHeight()/2 - i * vgap - vgap);//计算y轴坐标
             float y1=(getHeight()/2+i * vgap + vgap);
             //绘制频谱块
             mPaint.setColor(Color.WHITE);//画笔颜色
             canvas.drawLine(x, y, (x + strokeLength), y, mPaint);//绘制频谱块

             //绘制音量柱倒影
             if (i <= 6 && value > 0) {
                 mPaint.setColor(Color.WHITE);//画笔颜色
                 mPaint.setAlpha(100 - (100 / 6 * i));//倒影颜色
                 canvas.drawLine(x, y1, (x + strokeLength), y1, mPaint);//绘制频谱块
             }
         }
     }

     @Override
     public void onDraw(Canvas canvas) {
         int j=-4;
         for (int i = 0; i < CYLINDER_NUM/2-4; i++) { //绘制25个能量柱

             drawCylinder(canvas, strokeWidth / 2 + hgap + i * (hgap + strokeLength), mData[i]);
         }
         for(int i =CYLINDER_NUM; i>=CYLINDER_NUM/2-4; i--){
         j++;
             drawCylinder(canvas, strokeWidth / 2 + hgap + (CYLINDER_NUM/2+j-1 )* (hgap + strokeLength), mData[i-1]);
         }
     }

     /**
      * It sets the visualizer of the view. DO set the viaulizer to null when exit the program.
      *
      * @parma visualizer It is the visualizer to set.
      */
     public void setVisualizer(Visualizer visualizer) {
         if (visualizer != null) {
             if (!visualizer.getEnabled()) {
                 visualizer.setCaptureSize(Visualizer.getCaptureSizeRange()[0]);
             }
             levelStep = 230 / MAX_LEVEL;
             visualizer.setDataCaptureListener(this, Visualizer.getMaxCaptureRate() / 2, false, true);

         } else {

             if (mVisualizer != null) {
                 mVisualizer.setEnabled(false);
                 mVisualizer.release();
             }
         }
         mVisualizer = visualizer;
     }

     //这个回调应该采集的是快速傅里叶变换有关的数据
     @Override
     public void onFftDataCapture(Visualizer visualizer, byte[] fft, int samplingRate) {
         byte[] model = new byte[fft.length / 2 + 1];
         if (mDataEn) {
             model[0] = (byte) Math.abs(fft[1]);
             int j = 1;
             for (int i = 2; i < fft.length; ) {
                 model[j] = (byte) Math.hypot(fft[i], fft[i + 1]);
                 i += 2;
                 j++;
             }
         } else {
             for (int i = 0; i < CYLINDER_NUM; i++) {
                 model[i] = 0;
             }
         }
         for (int i = 0; i < CYLINDER_NUM; i++) {
             final byte a = (byte) (Math.abs(model[CYLINDER_NUM - i]) / levelStep);

             final byte b = mData[i];
             if (a > b) {
                 mData[i] = a;
             } else {
                 if (b > 0) {
                     mData[i]--;
                 }
             }
         }
         postInvalidate();//刷新界面
     }

     //这个回调应该采集的是波形数据
     @Override
     public void onWaveFormDataCapture(Visualizer visualizer, byte[] waveform, int samplingRate) {
         // Do nothing...
     }
 }

主界面activity：

 import android.app.Activity;
 import android.graphics.Color;
 import android.media.AudioManager;
 import android.media.MediaPlayer;
 import android.media.audiofx.Equalizer;
 import android.media.audiofx.Visualizer;
 import android.os.Bundle;
 import android.view.*;
 import android.widget.*;

 public class MyActivity extends Activity {

     private static final float VISUALIZER_HEIGHT_DIP = 150f;//频谱View高度

     private MediaPlayer mMediaPlayer;//音频
     private Visualizer mVisualizer;//频谱器
     private Equalizer mEqualizer; //均衡器

     private LinearLayout mLayout;//代码布局
     VisualizerView mBaseVisualizerView;

     ImageButton play;

     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);

         this.requestWindowFeature(Window.FEATURE_NO_TITLE);//去掉标题栏
         this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);//去掉信息栏

         setVolumeControlStream(AudioManager.STREAM_MUSIC);//设置音频流 - STREAM_MUSIC：音乐回放即媒体音量


         mLayout = new LinearLayout(this);//代码创建布局
         mLayout.setOrientation(LinearLayout.VERTICAL);//设置为线性布局-上下排列
 //        mLayout.setBackgroundResource(R.drawable.ac88o);//设置界面背景
         mLayout.setGravity(Gravity.CENTER);
         setContentView(mLayout);//将布局添加到 Activity

         mMediaPlayer = MediaPlayer.create(this, R.raw.aaaass);//实例化 MediaPlayer 并添加音频

         setupVisualizerFxAndUi();//添加频谱到界面
         setupEqualizeFxAndUi();//添加均衡器到界面
         setupPlayButton();//添加按钮到界面


         mVisualizer.setEnabled(true);//false 则不显示
         mMediaPlayer.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {

             @Override
             public void onCompletion(MediaPlayer mp) {
             }
         });

         mMediaPlayer.start();//开始播放
         mMediaPlayer.setLooping(true);//循环播放

     }

     /**
      * 通过mMediaPlayer返回的AudioSessionId创建一个优先级为0均衡器对象 并且通过频谱生成相应的UI和对应的事件
      */
     private void setupEqualizeFxAndUi() {

         TextView kongge = new TextView(this);
         kongge.setText("");
         kongge.setTextSize(10);
         mLayout.addView(kongge);

         mEqualizer = new Equalizer(0, mMediaPlayer.getAudioSessionId());
         mEqualizer.setEnabled(true);// 启用均衡器

         // 通过均衡器得到其支持的频谱引擎
         short bands = mEqualizer.getNumberOfBands();

         // getBandLevelRange 是一个数组，返回一组频谱等级数组，
         // 第一个下标为最低的限度范围
         // 第二个下标为最大的上限,依次取出
         final short minEqualizer = mEqualizer.getBandLevelRange()[0];
         final short maxEqualizer = mEqualizer.getBandLevelRange()[1];

         for (short i = 0; i < bands; i++) {
             final short band = i;

             TextView freqTextView = new TextView(this);
             freqTextView.setTextColor(Color.WHITE);
             freqTextView.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));
             freqTextView.setGravity(Gravity.CENTER_HORIZONTAL);

             // 取出中心频率
             freqTextView.setText((mEqualizer.getCenterFreq(band) / 1000) + "HZ");
             mLayout.addView(freqTextView);

             LinearLayout row = new LinearLayout(this);
             row.setOrientation(LinearLayout.HORIZONTAL);

             TextView minDbTextView = new TextView(this);
             minDbTextView.setTextColor(Color.WHITE);
             minDbTextView.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));
             minDbTextView.setText((minEqualizer / 100) + " dB");

             TextView maxDbTextView = new TextView(this);
             maxDbTextView.setTextColor(Color.WHITE);
             maxDbTextView.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));
             maxDbTextView.setText((maxEqualizer / 100) + " dB");

             LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT, 40);


             layoutParams.weight = 1;
             SeekBar seekbar = new SeekBar(this);
             seekbar.setLayoutParams(layoutParams);
             seekbar.setPadding(15, 0, 15, 0);
             seekbar.setThumb(getResources().getDrawable(R.drawable.seek_bar_dian_selector));
             seekbar.setThumbOffset(20);
             seekbar.setMax(maxEqualizer - minEqualizer);
             seekbar.setProgress(mEqualizer.getBandLevel(band));


             seekbar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {

                 @Override
                 public void onStopTrackingTouch(SeekBar seekBar) {
                 }

                 @Override
                 public void onStartTrackingTouch(SeekBar seekBar) {
                 }

                 @Override
                 public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                     mEqualizer.setBandLevel(band, (short) (progress + minEqualizer));
                 }
             });
             row.addView(minDbTextView);
             row.addView(seekbar);
             row.addView(maxDbTextView);

             mLayout.addView(row);

         }
         TextView eqTextView = new TextView(this);
         eqTextView.setTextColor(Color.WHITE);
         eqTextView.setText("均衡器");
         eqTextView.setGravity(Gravity.CENTER_HORIZONTAL);
         eqTextView.setTextSize(20);

         mLayout.addView(eqTextView);

     }

     /**
      * 生成一个VisualizerView对象，使音频频谱的波段能够反映到 VisualizerView上
      */
     private void setupVisualizerFxAndUi() {
         mBaseVisualizerView = new VisualizerView(this);

         mBaseVisualizerView.setLayoutParams(new ViewGroup.LayoutParams(
                 ViewGroup.LayoutParams.FILL_PARENT,//宽度
                 (int) (VISUALIZER_HEIGHT_DIP * getResources().getDisplayMetrics().density)//高度
         ));
         //将频谱View添加到布局
         mLayout.addView(mBaseVisualizerView);
         //实例化Visualizer，参数SessionId可以通过MediaPlayer的对象获得
         mVisualizer = new Visualizer(mMediaPlayer.getAudioSessionId());
         //采样 - 参数内必须是2的位数 - 如64,128,256,512,1024
         mVisualizer.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
         //设置允许波形表示，并且捕获它
         mBaseVisualizerView.setVisualizer(mVisualizer);
     }

     //播放按钮
     private void setupPlayButton() {
         play = new ImageButton(this);
         play.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));
         play.setBackgroundResource(R.drawable.new_main_activity_stop_up);
         play.setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View view) {
                 if (mMediaPlayer.isPlaying()) {
                     play.setBackgroundResource(R.drawable.new_main_activity_play_up);
                     mMediaPlayer.pause();
                 } else {
                     play.setBackgroundResource(R.drawable.new_main_activity_stop_up);
                     mMediaPlayer.start();
                 }
             }
         });

         mLayout.addView(play);
     }

     @Override
     protected void onPause() {
         super.onPause();
         if (isFinishing() && mMediaPlayer != null) {
             mVisualizer.release();
             mMediaPlayer.release();
             mEqualizer.release();
             mMediaPlayer = null;
         }
     }

 }

图示效果：

demo下载点击打开链接