Android拔高应用篇之模拟信号示波器（转）

Android提高应用篇之模拟信号示波器（转）
    本文结合SurfaceView实现一个Android版的手机模拟信号示波器(PS：以前也讲过J2ME版的手机示波器)。最近物联网炒得很火，作为手机软件开发者，如何在不修改手机硬件电路的前提下实现与第三方传感器结合呢？麦克风就是一个很好的ADC接口，通过麦克风与第三方传感器结合，再在软件里对模拟信号做相应的处理，就可以提供更丰富的传感化应用。

    本文程序使用8000hz的采样率，对X轴方向绘图的实时性要求较高，如果不降低X轴的分辨率，程序的实时性较差，因此程序对X轴数据缩小区间为8倍～16倍。由于采用16位采样，因此Y轴数据的高度相对于手机屏幕来说也偏大，程序也对Y轴数据做缩小，区间为1倍～10倍。在SurfaceView的OnTouchListener方法里加入了波形基线的位置调节，直接在SurfaceView控件上触摸即可控制整体波形偏上或偏下显示。

main.xml源码如下：

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<?xml version="1.0" encoding="utf-8"?>  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"      android:orientation="vertical" android:layout_width="fill_parent"      android:layout_height="fill_parent">      <LinearLayout android:id="@+id/LinearLayout01"          android:layout_height="wrap_content" android:layout_width="fill_parent"          android:orientation="horizontal">          <Button android:layout_height="wrap_content" android:id="@+id/btnStart"              android:text="开始" android:layout_width="80dip"></Button>          <Button android:layout_height="wrap_content" android:text="停止"              android:id="@+id/btnExit" android:layout_width="80dip"></Button>          <ZoomControls android:layout_width="wrap_content"              android:layout_height="wrap_content" android:id="@+id/zctlX"></ZoomControls>          <ZoomControls android:layout_width="wrap_content"              android:layout_height="wrap_content" android:id="@+id/zctlY"></ZoomControls>      </LinearLayout>      <SurfaceView android:id="@+id/SurfaceView01"          android:layout_height="fill_parent" android:layout_width="fill_parent"></SurfaceView>  </LinearLayout>  <?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <LinearLayout android:id="@+id/LinearLayout01"  android:layout_height="wrap_content" android:layout_width="fill_parent"  android:orientation="horizontal">  <Button android:layout_height="wrap_content" android:id="@+id/btnStart"   android:text="开始" android:layout_width="80dip"></Button>  <Button android:layout_height="wrap_content" android:text="停止"   android:id="@+id/btnExit" android:layout_width="80dip"></Button>  <ZoomControls android:layout_width="wrap_content"   android:layout_height="wrap_content" android:id="@+id/zctlX"></ZoomControls>  <ZoomControls android:layout_width="wrap_content"   android:layout_height="wrap_content" android:id="@+id/zctlY"></ZoomControls> </LinearLayout> <SurfaceView android:id="@+id/SurfaceView01"  android:layout_height="fill_parent" android:layout_width="fill_parent"></SurfaceView></LinearLayout> 

ClsOscilloscope.java是实现示波器的类库，包含AudioRecord操作线程和SurfaceView绘图线程的实现，两个线程同步操作，代码如下：

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package com.testOscilloscope;   import java.util.ArrayList;   import android.graphics.Canvas;   import android.graphics.Color;   import android.graphics.Paint;   import android.graphics.Rect;   import android.media.AudioRecord;   import android.view.SurfaceView;   public class ClsOscilloscope {       private ArrayList<short[]> inBuf = new ArrayList<short[]>();       private boolean isRecording = false;// 线程控制标记       /**       * X轴缩小的比例       */      public int rateX = 4;       /**       * Y轴缩小的比例       */      public int rateY = 4;       /**       * Y轴基线       */      public int baseLine = 0;       /**       * 初始化       */      public void initOscilloscope(int rateX, int rateY, int baseLine) {           this.rateX = rateX;           this.rateY = rateY;           this.baseLine = baseLine;       }       /**       * 开始       *        * @param recBufSize       *            AudioRecord的MinBufferSize       */      public void Start(AudioRecord audioRecord, int recBufSize, SurfaceView sfv,               Paint mPaint) {           isRecording = true;           new RecordThread(audioRecord, recBufSize).start();// 开始录制线程           new DrawThread(sfv, mPaint).start();// 开始绘制线程       }       /**       * 停止       */      public void Stop() {           isRecording = false;           inBuf.clear();// 清除       }       /**       * 负责从MIC保存数据到inBuf       *        * @author GV       *        */      class RecordThread extends Thread {           private int recBufSize;           private AudioRecord audioRecord;           public RecordThread(AudioRecord audioRecord, int recBufSize) {               this.audioRecord = audioRecord;               this.recBufSize = recBufSize;           }           public void run() {               try {                   short[] buffer = new short[recBufSize];                   audioRecord.startRecording();// 开始录制                   while (isRecording) {                       // 从MIC保存数据到缓冲区                       int bufferReadResult = audioRecord.read(buffer, 0,                               recBufSize);                       short[] tmpBuf = new short[bufferReadResult / rateX];                       for (int i = 0, ii = 0; i < tmpBuf.length; i++, ii = i                               * rateX) {                           tmpBuf[i] = buffer[ii];                       }                       synchronized (inBuf) {//                           inBuf.add(tmpBuf);// 添加数据                       }                   }                   audioRecord.stop();               } catch (Throwable t) {               }           }       };       /**       * 负责绘制inBuf中的数据       *        * @author GV       *        */      class DrawThread extends Thread {           private int oldX = 0;// 上次绘制的X坐标           private int oldY = 0;// 上次绘制的Y坐标           private SurfaceView sfv;// 画板           private int X_index = 0;// 当前画图所在屏幕X轴的坐标           private Paint mPaint;// 画笔           public DrawThread(SurfaceView sfv, Paint mPaint) {               this.sfv = sfv;               this.mPaint = mPaint;           }           public void run() {               while (isRecording) {                   ArrayList<short[]> buf = new ArrayList<short[]>();                   synchronized (inBuf) {                       if (inBuf.size() == 0)                           continue;                       buf = (ArrayList<short[]>) inBuf.clone();// 保存                       inBuf.clear();// 清除                   }                   for (int i = 0; i < buf.size(); i++) {                       short[] tmpBuf = buf.get(i);                       SimpleDraw(X_index, tmpBuf, rateY, baseLine);// 把缓冲区数据画出来                       X_index = X_index + tmpBuf.length;                       if (X_index > sfv.getWidth()) {                           X_index = 0;                       }                   }               }           }           /**           * 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           */          void SimpleDraw(int start, short[] buffer, int rate, int baseLine) {               if (start == 0)                   oldX = 0;               Canvas canvas = sfv.getHolder().lockCanvas(                       new Rect(start, 0, start + buffer.length, sfv.getHeight()));// 关键:获取画布               canvas.drawColor(Color.BLACK);// 清除背景               int y;               for (int i = 0; i < buffer.length; i++) {// 有多少画多少                   int x = i + start;                   y = buffer[i] / rate + baseLine;// 调节缩小比例，调节基准线                   canvas.drawLine(oldX, oldY, x, y, mPaint);                   oldX = x;                   oldY = y;               }               sfv.getHolder().unlockCanvasAndPost(canvas);// 解锁画布，提交画好的图像           }       }   }

package com.testOscilloscope;import java.util.ArrayList;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Rect;import android.media.AudioRecord;import android.view.SurfaceView;public class ClsOscilloscope { private ArrayList<short[]> inBuf = new ArrayList<short[]>(); private boolean isRecording = false;// 线程控制标记 /**  * X轴缩小的比例  */ public int rateX = 4; /**  * Y轴缩小的比例  */ public int rateY = 4; /**  * Y轴基线  */ public int baseLine = 0; /**  * 初始化  */ public void initOscilloscope(int rateX, int rateY, int baseLine) {  this.rateX = rateX;  this.rateY = rateY;  this.baseLine = baseLine; } /**  * 开始  *   * @param recBufSize  *            AudioRecord的MinBufferSize  */ public void Start(AudioRecord audioRecord, int recBufSize, SurfaceView sfv,   Paint mPaint) {  isRecording = true;  new RecordThread(audioRecord, recBufSize).start();// 开始录制线程  new DrawThread(sfv, mPaint).start();// 开始绘制线程 } /**  * 停止  */ public void Stop() {  isRecording = false;  inBuf.clear();// 清除 } /**  * 负责从MIC保存数据到inBuf  *   * @author GV  *   */ class RecordThread extends Thread {  private int recBufSize;  private AudioRecord audioRecord;  public RecordThread(AudioRecord audioRecord, int recBufSize) {   this.audioRecord = audioRecord;   this.recBufSize = recBufSize;  }  public void run() {   try {    short[] buffer = new short[recBufSize];    audioRecord.startRecording();// 开始录制    while (isRecording) {     // 从MIC保存数据到缓冲区     int bufferReadResult = audioRecord.read(buffer, 0,       recBufSize);     short[] tmpBuf = new short[bufferReadResult / rateX];     for (int i = 0, ii = 0; i < tmpBuf.length; i++, ii = i       * rateX) {      tmpBuf[i] = buffer[ii];     }     synchronized (inBuf) {//      inBuf.add(tmpBuf);// 添加数据     }    }    audioRecord.stop();   } catch (Throwable t) {   }  } }; /**  * 负责绘制inBuf中的数据  *   * @author GV  *   */ class DrawThread extends Thread {  private int oldX = 0;// 上次绘制的X坐标  private int oldY = 0;// 上次绘制的Y坐标  private SurfaceView sfv;// 画板  private int X_index = 0;// 当前画图所在屏幕X轴的坐标  private Paint mPaint;// 画笔  public DrawThread(SurfaceView sfv, Paint mPaint) {   this.sfv = sfv;   this.mPaint = mPaint;  }  public void run() {   while (isRecording) {    ArrayList<short[]> buf = new ArrayList<short[]>();    synchronized (inBuf) {     if (inBuf.size() == 0)      continue;     buf = (ArrayList<short[]>) inBuf.clone();// 保存     inBuf.clear();// 清除    }    for (int i = 0; i < buf.size(); i++) {     short[] tmpBuf = buf.get(i);     SimpleDraw(X_index, tmpBuf, rateY, baseLine);// 把缓冲区数据画出来     X_index = X_index + tmpBuf.length;     if (X_index > sfv.getWidth()) {      X_index = 0;     }    }   }  }  /**   * 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   */  void SimpleDraw(int start, short[] buffer, int rate, int baseLine) {   if (start == 0)    oldX = 0;   Canvas canvas = sfv.getHolder().lockCanvas(     new Rect(start, 0, start + buffer.length, sfv.getHeight()));// 关键:获取画布   canvas.drawColor(Color.BLACK);// 清除背景   int y;   for (int i = 0; i < buffer.length; i++) {// 有多少画多少    int x = i + start;    y = buffer[i] / rate + baseLine;// 调节缩小比例，调节基准线    canvas.drawLine(oldX, oldY, x, y, mPaint);    oldX = x;    oldY = y;   }   sfv.getHolder().unlockCanvasAndPost(canvas);// 解锁画布，提交画好的图像  } }} 

testOscilloscope.java是主程序，控制UI和ClsOscilloscope，代码如下：

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package com.testOscilloscope;   import android.app.Activity;   import android.graphics.Color;   import android.graphics.Paint;   import android.media.AudioFormat;   import android.media.AudioRecord;   import android.media.MediaRecorder;   import android.os.Bundle;   import android.view.MotionEvent;   import android.view.SurfaceView;   import android.view.View;   import android.view.View.OnTouchListener;   import android.widget.Button;   import android.widget.ZoomControls;   public class testOscilloscope extends Activity {       /** Called when the activity is first created. */      Button btnStart,btnExit;       SurfaceView sfv;       ZoomControls zctlX,zctlY;              ClsOscilloscope clsOscilloscope=new ClsOscilloscope();              static final int frequency = 8000;//分辨率       static final int channelConfiguration = AudioFormat.CHANNEL_CONFIGURATION_MONO;       static final int audioEncoding = AudioFormat.ENCODING_PCM_16BIT;       static final int xMax = 16;//X轴缩小比例最大值,X轴数据量巨大，容易产生刷新延时       static final int xMin = 8;//X轴缩小比例最小值       static final int yMax = 10;//Y轴缩小比例最大值       static final int yMin = 1;//Y轴缩小比例最小值              int recBufSize;//录音最小buffer大小       AudioRecord audioRecord;       Paint mPaint;       @Override      public void onCreate(Bundle savedInstanceState) {           super.onCreate(savedInstanceState);           setContentView(R.layout.main);           //录音组件           recBufSize = AudioRecord.getMinBufferSize(frequency,                   channelConfiguration, audioEncoding);           audioRecord = new AudioRecord(MediaRecorder.AudioSource.MIC, frequency,                   channelConfiguration, audioEncoding, recBufSize);           //按键           btnStart = (Button) this.findViewById(R.id.btnStart);           btnStart.setOnClickListener(new ClickEvent());           btnExit = (Button) this.findViewById(R.id.btnExit);           btnExit.setOnClickListener(new ClickEvent());           //画板和画笔           sfv = (SurfaceView) this.findViewById(R.id.SurfaceView01);            sfv.setOnTouchListener(new TouchEvent());           mPaint = new Paint();             mPaint.setColor(Color.GREEN);// 画笔为绿色             mPaint.setStrokeWidth(1);// 设置画笔粗细            //示波器类库           clsOscilloscope.initOscilloscope(xMax/2, yMax/2, sfv.getHeight()/2);                      //缩放控件，X轴的数据缩小的比率高些           zctlX = (ZoomControls)this.findViewById(R.id.zctlX);           zctlX.setOnZoomInClickListener(new View.OnClickListener() {               @Override              public void onClick(View v) {                   if(clsOscilloscope.rateX>xMin)                       clsOscilloscope.rateX--;                   setTitle("X轴缩小"+String.valueOf(clsOscilloscope.rateX)+"倍"                          +","+"Y轴缩小"+String.valueOf(clsOscilloscope.rateY)+"倍");               }           });           zctlX.setOnZoomOutClickListener(new View.OnClickListener() {               @Override              public void onClick(View v) {                   if(clsOscilloscope.rateX<xMax)                       clsOscilloscope.rateX++;                       setTitle("X轴缩小"+String.valueOf(clsOscilloscope.rateX)+"倍"                          +","+"Y轴缩小"+String.valueOf(clsOscilloscope.rateY)+"倍");               }           });           zctlY = (ZoomControls)this.findViewById(R.id.zctlY);           zctlY.setOnZoomInClickListener(new View.OnClickListener() {               @Override              public void onClick(View v) {                   if(clsOscilloscope.rateY>yMin)                       clsOscilloscope.rateY--;                   setTitle("X轴缩小"+String.valueOf(clsOscilloscope.rateX)+"倍"                          +","+"Y轴缩小"+String.valueOf(clsOscilloscope.rateY)+"倍");               }           });                      zctlY.setOnZoomOutClickListener(new View.OnClickListener() {               @Override              public void onClick(View v) {                   if(clsOscilloscope.rateY<yMax)                       clsOscilloscope.rateY++;                       setTitle("X轴缩小"+String.valueOf(clsOscilloscope.rateX)+"倍"                          +","+"Y轴缩小"+String.valueOf(clsOscilloscope.rateY)+"倍");               }           });       }       @Override      protected void onDestroy() {           super.onDestroy();           android.os.Process.killProcess(android.os.Process.myPid());       }              /**       * 按键事件处理       * @author GV       *       */      class ClickEvent implements View.OnClickListener {           @Override          public void onClick(View v) {               if (v == btnStart) {                   clsOscilloscope.baseLine=sfv.getHeight()/2;                   clsOscilloscope.Start(audioRecord,recBufSize,sfv,mPaint);               } else if (v == btnExit) {                   clsOscilloscope.Stop();               }           }       }       /**       * 触摸屏动态设置波形图基线       * @author GV       *       */      class TouchEvent implements OnTouchListener{           @Override          public boolean onTouch(View v, MotionEvent event) {               clsOscilloscope.baseLine=(int)event.getY();               return true;           }                  }   } 

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