这个类是有三个功能，第一，采集数据；第二，进行快速傅里叶计算；第三，绘图。
采集数据用AudioRecord类，网上讲解这个类的蛮多的，搞清楚构造类的各个参数就可以。
绘图用的是SurfaceView Paint Canvas三个类，本人也是参考网络达人的代码
package com.mobao360.sunshine; import java.util.ArrayList; import java.lang.Short; import Android.content.Context; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.DashPathEffect; import android.graphics.Paint; import android.graphics.Path; import android.graphics.PathEffect; import android.graphics.Rect; import android.media.AudioRecord; import android.util.Log; import android.view.SurfaceView; public class AudioProcess { public static final float pi= (float) 3.1415926; //应该把处理前后处理后的普线都显示出来 private ArrayList<short[]> inBuf = new ArrayList<short[]>();//原始录入数据 private ArrayList<int[]> outBuf = new ArrayList<int[]>();//处理后的数据 private boolean isRecording = false; Context mContext; private int shift = 30; public int frequence = 0; private int length = 256; //y轴缩小的比例 public int rateY = 21; //y轴基线 public int baseLine = 0; //初始化画图的一些参数 public void initDraw(int rateY, int baseLine,Context mContext, int frequence){ this.mContext = mContext; this.rateY = rateY; this.baseLine = baseLine; this.frequence = frequence; } //启动程序 public void start(AudioRecord audioRecord, int minBufferSize, SurfaceView sfvSurfaceView) { isRecording = true; new RecordThread(audioRecord, minBufferSize).start(); new DrawThread(sfvSurfaceView).start(); } //停止程序 public void stop(SurfaceView sfvSurfaceView){ isRecording = false; inBuf.clear(); } //录音线程 class RecordThread extends Thread{ private AudioRecord audioRecord; private int minBufferSize; public RecordThread(AudioRecord audioRecord,int minBufferSize){ this.audioRecord = audioRecord; this.minBufferSize = minBufferSize; } public void run(){ try{ short[] buffer = new short[minBufferSize]; audioRecord.startRecording(); while(isRecording){ int res = audioRecord.read(buffer, 0, minBufferSize); synchronized (inBuf){ inBuf.add(buffer); } //保证长度为2的幂次数 length=up2int(res); short[]tmpBuf = new short[length]; System.arraycopy(buffer, 0, tmpBuf, 0, length); Complex[]complexs = new Complex[length]; int[]outInt = new int[length]; for(int i=0;i < length; i++){ Short short1 = tmpBuf[i]; complexs[i] = new Complex(short1.doubleValue()); } fft(complexs,length); for (int i = 0; i < length; i++) { outInt[i] = complexs[i].getIntValue(); } synchronized (outBuf) { outBuf.add(outInt); } } audioRecord.stop(); }catch (Exception e) { // TODO: handle exception Log.i("Rec E",e.toString()); } } } //绘图线程 class DrawThread extends Thread{ //画板 private SurfaceView sfvSurfaceView; //当前画图所在屏幕x轴的坐标 //画笔 private Paint mPaint; private Paint tPaint; private Paint dashPaint; public DrawThread(SurfaceView sfvSurfaceView) { this.sfvSurfaceView = sfvSurfaceView; //设置画笔属性 mPaint = new Paint(); mPaint.setColor(Color.BLUE); mPaint.setStrokeWidth(2); mPaint.setAntiAlias(true); tPaint = new Paint(); tPaint.setColor(Color.YELLOW); tPaint.setStrokeWidth(1); tPaint.setAntiAlias(true); //画虚线 dashPaint = new Paint(); dashPaint.setStyle(Paint.Style.STROKE); dashPaint.setColor(Color.GRAY); Path path = new Path(); path.moveTo(0, 10); path.lineTo(480,10); PathEffect effects = new DashPathEffect(new float[]{5,5,5,5},1); dashPaint.setPathEffect(effects); } @SuppressWarnings("unchecked") public void run() { while (isRecording) { ArrayList<int[]>buf = new ArrayList<int[]>(); synchronized (outBuf) { if (outBuf.size() == 0) { continue; } buf = (ArrayList<int[]>)outBuf.clone(); outBuf.clear(); } //根据ArrayList中的short数组开始绘图 for(int i = 0; i < buf.size(); i++){ int[]tmpBuf = buf.get(i); SimpleDraw(tmpBuf, rateY, baseLine); } } } /** * 绘制指定区域 * * @param start * X 轴开始的位置(全屏) * @param buffer * 缓冲区 * @param rate * Y 轴数据缩小的比例 * @param baseLine * Y 轴基线 */ private void SimpleDraw(int[] buffer, int rate, int baseLine){ Canvas canvas = sfvSurfaceView.getHolder().lockCanvas( new Rect(0, 0, buffer.length,sfvSurfaceView.getHeight())); canvas.drawColor(Color.BLACK); canvas.drawText("幅度值", 0, 3, 2, 15, tPaint); canvas.drawText("原点(0,0)", 0, 7, 5, baseLine + 15, tPaint); canvas.drawText("频率(HZ)", 0, 6, sfvSurfaceView.getWidth() - 50, baseLine + 30, tPaint); canvas.drawLine(shift, 20, shift, baseLine, tPaint); canvas.drawLine(shift, baseLine, sfvSurfaceView.getWidth(), baseLine, tPaint); canvas.save(); canvas.rotate(30, shift, 20); canvas.drawLine(shift, 20, shift, 30, tPaint); canvas.rotate(-60, shift, 20); canvas.drawLine(shift, 20, shift, 30, tPaint); canvas.rotate(30, shift, 20); canvas.rotate(30, sfvSurfaceView.getWidth()-1, baseLine); canvas.drawLine(sfvSurfaceView.getWidth() - 1, baseLine, sfvSurfaceView.getWidth() - 11, baseLine, tPaint); canvas.rotate(-60, sfvSurfaceView.getWidth()-1, baseLine); canvas.drawLine(sfvSurfaceView.getWidth() - 1, baseLine, sfvSurfaceView.getWidth() - 11, baseLine, tPaint); canvas.restore(); //tPaint.setStyle(Style.STROKE); for(int index = 64; index <= 512; index = index + 64){ canvas.drawLine(shift + index, baseLine, shift + index, 40, dashPaint); String str = String.valueOf(frequence / 1024 * index); canvas.drawText( str, 0, str.length(), shift + index - 15, baseLine + 15, tPaint); } int y; for(int i = 0; i < buffer.length; i = i + 1){ y = baseLine - buffer[i] / rateY ; canvas.drawLine(2*i + shift, baseLine, 2*i +shift, y, mPaint); } sfvSurfaceView.getHolder().unlockCanvasAndPost(canvas); } } /** * 向上取最接近iint的2的幂次数.比如iint=320时,返回256 * @param iint * @return */ private int up2int(int iint) { int ret = 1; while (ret<=iint) { ret = ret << 1; } return ret>>1; } //快速傅里叶变换 public void fft(Complex[] xin,int N) { int f,m,N2,nm,i,k,j,L;//L:运算级数 float p; int e2,le,B,ip; Complex w = new Complex(); Complex t = new Complex(); N2 = N / 2;//每一级中蝶形的个数,同时也代表m位二进制数最高位的十进制权值 f = N;//f是为了求流程的级数而设立的 for(m = 1; (f = f / 2) != 1; m++); //得到流程图的共几级 nm = N - 2; j = N2; /******倒序运算——雷德算法******/ for(i = 1; i <= nm; i++) { if(i < j)//防止重复交换 { t = xin[j]; xin[j] = xin[i]; xin[i] = t; } k = N2; while(j >= k) { j = j - k; k = k / 2; } j = j + k; } /******蝶形图计算部分******/ for(L=1; L<=m; L++) //从第1级到第m级 { e2 = (int) Math.pow(2, L); //e2=(int)2.pow(L); le=e2+1; B=e2/2; for(j=0;j<B;j++) //j从0到2^(L-1)-1 { p=2*pi/e2; w.real = Math.cos(p * j); //w.real=Math.cos((double)p*j); //系数W w.image = Math.sin(p*j) * -1; //w.imag = -sin(p*j); for(i=j;i<N;i=i+e2) //计算具有相同系数的数据 { ip=i+B; //对应蝶形的数据间隔为2^(L-1) t=xin[ip].cc(w); xin[ip] = xin[i].cut(t); xin[i] = xin[i].sum(t); } } } } }