NullPointer异常2D数组类

我有两个类，MainActivity和HjorthClass。NullPointer异常2D数组类

我有一个空指针异常，我相信是来自我的数组，但我找不出错误在哪里。

请将您的注意力引向MainActivity中的TestSeizureDetected（）。当我按下调用该方法的按钮时，会发生此问题。我没有包含巨大的字符串，因为它包含7681个单独的数字。

的

String huge = "1.3870574e+01 2.0512821e+01 3.8485958e+01 4.9816850e+01 6.7789988e+01 6.7789988e+01 6.5836386e+01 7.7557998e+01 8.2246642e+01"

的基本格式格式请参考下面MainActivity，HjorthClass，以及相关的logcat出现错误时。

MainActivity

package com.example.android.BluetoothChat; 


import android.R.string; 
import android.app.Activity; 
import android.bluetooth.BluetoothAdapter; 
import android.content.Context; 
import android.content.Intent; 
import android.location.Location; 
import android.location.LocationListener; 
import android.location.LocationManager; 
import android.net.Uri; 
import android.os.Bundle; 
import android.os.CountDownTimer; 
import android.os.Handler; 
import android.speech.tts.TextToSpeech; 
import android.speech.tts.TextToSpeech.OnInitListener; 
import android.telephony.SmsManager; 
import android.util.Log; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.ArrayAdapter; 
import android.widget.Button; 
import android.widget.ListView; 
import android.widget.TextView; 
import android.widget.Toast; 

import java.util.Locale; 
import java.util.Set; 
import android.bluetooth.BluetoothDevice; 

import java.io.BufferedReader; 
import java.io.FileNotFoundException; 
import java.io.FileReader; 
import java.io.InputStream; 
import java.io.OutputStream; 
import java.io.Reader; 

import android.bluetooth.BluetoothSocket; 
import android.widget.EditText; 
import java.io.IOException; 
import java.util.UUID; 

public class MainActivity extends Activity implements LocationListener{ 
    Button start, stop; 
    Button textData; 
    TextView tv; 
    TextView tv2; 
    TextView sum; 
    TextView textResult; 
    LocationManager lm; 
    static TextToSpeech Talker; 
    TextView myLabel; 
    Handler mhandler = new Handler(); 
    int i; 
    int sum1 = 0; 
    static BluetoothDevice mmDevice; 
    static BluetoothAdapter mBluetoothAdapter; 
    static BluetoothSocket mmSocket; 
    String lat; 
    String lon; 
    public MyCounter timer; 
    public double[][] finalSeizureData= new double[7681][1]; 

    EditText myTextbox; 
    static OutputStream mmOutputStream; 
    static InputStream mmInputStream; 
    static Thread workerThread; 
    static byte[] readBuffer; 
    static int readBufferPosition; 
    static int counter; 
    static volatile boolean stopWorker; 
    TextToSpeech talker; 
    public HjorthClass testValue; 


@Override 
protected void onCreate(Bundle savedInstanceState) { 
super.onCreate(savedInstanceState); 
     setContentView(R.layout.main2); 
     setTitle("Seizure Detection Helmet Application"); 

     myTextbox = (EditText)this.findViewById(R.id.name); 
     talker = new TextToSpeech(getApplicationContext(),new TextToSpeech.OnInitListener() { 
      @Override 

      public void onInit(int status) { 
       if(status != TextToSpeech.ERROR) 
       { 
       talker.setLanguage(Locale.US); 
       } 

      } 
     }); 

     //if(BluetoothChat.finalValue.returnSum()== true)//TRYING TO USE THE VALUE FROM BLUETOOTH CHAT HERE! ERROR HERE, finalValue cannot be resolved to this variable. 
     //{ 
     //SeizureDetected(); 
     //} 

     //Initialize Counter Sequence 
     start = (Button)findViewById(R.id.start);// Launch seishor Sequence 
     stop = (Button)findViewById(R.id.stop);//Override Function 
     textData =(Button)findViewById(R.id.talk); 
     tv = (TextView)findViewById(R.id.tv); 
     tv.setText("30"); // starting from 30. 
     sum = (TextView)findViewById(R.id.sum); 
     myLabel = (TextView)findViewById(R.id.result); 
     textResult = (TextView)findViewById(R.id.TextSeizure); 


    final MyCounter timer = new MyCounter(30000,1000); 
    final Runnable sumTask = new Runnable() 
    { 
    @Override 
    public void run() 
    { 
i++; 
sum1 = sum1+i; 
if(sum1>120) 
{ 
start.setEnabled(true); 
    timer.start(); 
return; 
} 
sum.setText("Sum:"+sum1); 
mhandler.postDelayed(this,1000); 
    } 
    }; 




     start.setOnClickListener(new OnClickListener() { 
      @Override 
      public void onClick(View v){ 
      start.setEnabled(false); 
      timer.start(); 
      speakOut(); 

     } 
     }); 
     stop.setOnClickListener(new OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       timer.cancel(); 
       tv.setText("Emergency Call to first responders prevented"); 
      } 
     }); 

     textData.setOnClickListener(new OnClickListener() { 
      @Override 
      public void onClick(View v){ 
       TestSeizureDetected(); 

     } 
     }); 




     //Initialize GPS layout 
     tv2 = (TextView) findViewById(R.id.GPS); 
     lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE); 
     lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 1000, 1, this); 
} 
    public class MyCounter extends CountDownTimer{ 

     public MyCounter(long millisInFuture, long countDownInterval) { 
      super(millisInFuture, countDownInterval); 
     } 

     @Override 
     public void onFinish() { 
      System.out.println("Timer Completed."); 
      tv.setText("Sending information to first responders."); 
      String name = myTextbox.getText().toString(); 
      String textMessage = "Hello my name is "+ name + " Help I need help, I have tonic clonic seizures at latitudinal coordinates " + lat + " and longitudinal coordinates "+ lon; 
      String phoneNumber = "7034004407"; 
      SmsManager.getDefault().sendTextMessage(phoneNumber, null, textMessage, null, null); 


      //phone.setData(Uri.parse("tel:7034004407")); 
      //startActivity(phone); 

     } 

     @Override 
     public void onTick(long millisUntilFinished) { 
      tv.setText((millisUntilFinished/1000)+""); 
      System.out.println("Timer : " + (millisUntilFinished/1000)); 
     } 
    } 

    @Override 

    public void onLocationChanged(Location arg0) 
    { 
     lat = String.valueOf(arg0.getLatitude()); 
     lon = String.valueOf(arg0.getLongitude()); 
     Log.e("GPS", "location changed: lat="+lat+", lon="+lon); 
     tv2.setText("lat="+lat+", long="+lon); 
    } 
    public void onProviderDisabled(String arg0) { 
     Log.e("GPS", "provider disabled " + arg0); 
    } 
    public void onProviderEnabled(String arg0) { 
     Log.e("GPS", "provider enabled " + arg0); 
    } 
    public void onStatusChanged(String arg0, int arg1, Bundle arg2) { 
     Log.e("GPS", "status changed to " + arg0 + " [" + arg1 + "]"); 
    } 

    public void SeizureDetected() 
    { 
     timer.start(); 
     speakOut(); 
    } 

    public void TestSeizureDetected() 
    { 
     String[] temp = huge.split("\\s+"); 
     double[] convert = new double[temp.length]; 
     for(int y = 0; y<convert.length; y++) 
     { 
      convert[y]= Double.parseDouble(temp[y]); 
     } 
     for(int i = 0; i<convert.length;i++) 
     { 
      for(int j = 0; j<1;j++) 
      { 
       finalSeizureData[i][j] = convert[j]; 
      } 
     } 
     testValue = new HjorthClass(finalSeizureData); 
     if(testValue.returnSum()== true) 
     { 
      textResult.setText("Seizure has been detected in Text File"); 
     } 

    } 


    public void speakOut() 

    { 
     String original = ("You will have a seizure in thirty seconds. You will have a seizure shortly. Please arrange yourself in a safe position. You will have a seizure shortly. Please arrange yourself in a safe position. You will have a seizure shortly. Please arrange yourself in a safe position. You will have a seish shortly. Please arrange yourself in a safe position."); 
     talker.speak(original, TextToSpeech.QUEUE_FLUSH, null); 
    } 


}

HjorthClass

package com.example.android.BluetoothChat; 

import android.app.Activity; 

public class HjorthClass extends Activity{ 
public double [][]Active; 
public int height; 
public int width; 
public double [][] d1; 
public double [][] d2; 
public double [][] m0; 
public double [][] threshold; 
public double sum; 

//check length of height 
public HjorthClass (double [][]Active) 
{ 
    height = Active[0].length; 
    width = Active[1].length; 

    for(int i = 0; i<height; i++)// 1st differential subtracting from previous row 
    { 
     if(i == 0) 
     { 
      d1[0][0] = Active[0][0]; 
     } 
     else 
     { 
      for(int j =0; j < width; j++) 
      { 
       d1[i][j] = Active[i][j]-Active[i-1][j]; 
      } 
     }  
    } 

    for(int i = 0; i<d1[0].length; i++)// 2nd differential subtracting from the row before 
    { 
     if(i == 0) 
     { 
      d2[0][0] = d1[0][0]; //since no previous row -- the difference between the previous row(non-existant) and this row is assumed to be this value 
     } 
     else 
     { 
      for(int j =0; j <width; j++) 
      { 
       d2[i][j] = d1[i][j]- d1[i-1][j]; 
      } 
     }  
    } 

    for(int i = 0; i<height; i++)// Original moving average - is used for Activity 
    { 
     if(i == 0) 
     { 
      m0[0][0] = Active[i][i]/2; 
     } 
     else 
     { 
      for(int j =0; j < width; j++) 
      { 
       m0[i][j] = (Active[i][j]- Active[i-1][j])/2; 
      } 
     }  
    } 

    for(int i = 0; i<m0[0].length; i++)// Threshold, if the value is of the moving average at each data point is greater than 10,000, program outputs 1, otherwise 0 
    { 
      for(int j =0; j < width; j++) 
      { 
      if(m0[i][j] >= 10000) 
      { 
       threshold[i][j] = 1; 
      } 
      else 
      { 
       threshold[i][j]=0; 
      } 
      } 
    } 

    for(int i = 0; i<threshold[0].length; i++)// Sum of all the values 
    { 
      for(int j =0; j < width; j++) 
      { 
       sum = sum + threshold[i][j]; 
      } 
    } 
} 
    public boolean returnSum() 
    { 
     if(sum >= 300) 
     { 
      return true; 
     } 
     else 
     return false; 
    } 


}

logcat的

04-01 17:59:00.836: D/dalvikvm(3506): GC_CONCURRENT freed 90K, 38% free 4146K/6663K, external 2002K/2137K, paused 9ms+2ms 
04-01 17:59:01.176: D/dalvikvm(3506): GC_CONCURRENT freed 323K, 36% free 4994K/7751K, external 2002K/2137K, paused 3ms+2ms 
04-01 17:59:01.466: D/dalvikvm(3506): GC_CONCURRENT freed 1513K, 45% free 4956K/8903K, external 2002K/2137K, paused 2ms+4ms 
04-01 17:59:01.486: D/AndroidRuntime(3506): Shutting down VM 
04-01 17:59:01.486: W/dalvikvm(3506): threadid=1: thread exiting with uncaught exception (group=0x40015560) 
04-01 17:59:01.496: E/AndroidRuntime(3506): FATAL EXCEPTION: main 
04-01 17:59:01.496: E/AndroidRuntime(3506): java.lang.NullPointerException 
04-01 17:59:01.496: E/AndroidRuntime(3506):  at com.example.android.BluetoothChat.HjorthClass.<init>(HjorthClass.java:27) 
04-01 17:59:01.496: E/AndroidRuntime(3506):  at com.example.android.BluetoothChat.MainActivity.TestSeizureDetected(MainActivity.java:236) 
04-01 17:59:01.496: E/AndroidRuntime(3506):  at com.example.android.BluetoothChat.MainActivity$5.onClick(MainActivity.java:154) 
04-01 17:59:01.496: E/AndroidRuntime(3506):  at android.view.View.performClick(View.java:2485) 
04-01 17:59:01.496: E/AndroidRuntime(3506):  at android.view.View$PerformClick.run(View.java:9080) 
04-01 17:59:01.496: E/AndroidRuntime(3506):  at android.os.Handler.handleCallback(Handler.java:587) 
04-01 17:59:01.496: E/AndroidRuntime(3506):  at android.os.Handler.dispatchMessage(Handler.java:92) 
04-01 17:59:01.496: E/AndroidRuntime(3506):  at android.os.Looper.loop(Looper.java:130) 
04-01 17:59:01.496: E/AndroidRuntime(3506):  at android.app.ActivityThread.main(ActivityThread.java:3683) 
04-01 17:59:01.496: E/AndroidRuntime(3506):  at java.lang.reflect.Method.invokeNative(Native Method) 
04-01 17:59:01.496: E/AndroidRuntime(3506):  at java.lang.reflect.Method.invoke(Method.java:507) 
04-01 17:59:01.496: E/AndroidRuntime(3506):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
04-01 17:59:01.496: E/AndroidRuntime(3506):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
04-01 17:59:01.496: E/AndroidRuntime(3506):  at dalvik.system.NativeStart.main(Native Method) 
04-01 17:59:23.046: I/Process(3506): Sending signal. PID: 3506 SIG: 9

来源

2014-04-01 user3385015

什么在行27 @'HjorthClass'？ –

我如何知道它是什么行号？你能列出代码吗？ – user3385015

问题出在TestSeizureDetected的第236行，它正在调用HjorthClass的构造函数：类似于'new HjorthClass（参数，参数，空参数，参数）的代码'null参数被严重处理并导致构造函数失败。 – Aarowaim

在尝试访问d1，d2，m0或threshold阵列中的任何值之前，应对它们进行初始化。我可以对于需要大小是错误的，但你可以尝试以下

public HjorthClass (double [][]Active) 
{ 
    height = Active[0].length; 
    width = Active[1].length; 
    d1 = new double[height][width]; 
    d2 = new double[height][width]; 
....

但你也可能要使用ArrayList<ArrayList<Double>>保留数据，如果你不知道的结构，你将要使用的大小。

来源

2014-04-01 18:22:10 nikis

你不初始化d1和d2，您需要使用上HjorthClass

之前初始化

来源

2014-04-01 18:17:49

它看起来像你设置finalSeizureData（一个双数组）隐式（单个数组）。即新双[7681] [1] = 新双[临时长度]。所以我认为你的变量finalSeizureData将总是包含1个单个数组。您没有正确设置阵列。我可能不得不写一个快速测试案例...

来源

2014-04-01 19:18:40 Snake

我不相信这是真的。我将位置j的转换值设置为finalSeizureData的位置[i] [j]的值。 – user3385015

NullPointer异常2D数组类

回答

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