Question

这是主要活动我试图将类移动到一个新文件一旦我这样做，我就无法成功召集课程以下代码生成空指针，但指针不为null 我不能简单地将savedTrainInfo类更改为static，因为然后文件例程将无法正常工作。必须有一个简单的解决方案为清晰起见，我需要将我的课程分开。

import mp.trains.conductor.savedTrainInfo;
public class trains extends Activity 
  {
  private savedTrainInfo msavedTrainInfo;
  protected static Context context;

  public void onCreate(Bundle savedInstanceState) 
    {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.main);
    trains.context=getApplicationContext();  
    msavedTrainInfo=new savedTrainInfo();
    msavedTrainInfo.getTrainAttributes();
    }
  }

新文件这里有很多功能;主要是文件I / O. 如果位于主要活动列车中，这些都可以正常工作你是对的。错误似乎在if（readStartupFile（trainAttributes）== false）

public class savedTrainInfo extends trains
  {
  public void getTrainAttributes()
    {
    trainAttributes=new String [10];
if (readStartupFile(trainAttributes)==false)
  {
  fileLine=0;
  }
else
  {
  try 
    {
    fileLine = Integer.parseInt(trainAttributes[0].toString());
    } 
  catch(NumberFormatException nfe) 
    {
    System.out.println("Could not parse " + nfe);
    } 
  }
    }

  public  boolean readStartupFile(String objects[])
    {
    try 
    {
// InputStream fHandle = openFileInput("startupTrains.txt");
InputStream fHandle = trains.context.openFileInput("startupTrains.txt");
if (fHandle != null) 
  {
  // prepare the file for reading
  InputStreamReader inputreader = new InputStreamReader(fHandle);
  BufferedReader buffreader = new BufferedReader(inputreader);
  String line;
  line = buffreader.readLine();
  if (line == null)
    {
    fHandle.close();
    return false;
    }
  else
    {
    String[] item = (line).split(",");                  
    objects[0]=item[0].toString();                      
    fHandle.close();
    }
  return true;
  }
else
  {
  return false;
  }
}
catch (FileNotFoundException e2) 
  {
  return false;
  } 
catch (IOException e) 
{
e.printStackTrace();
return false;
}
}

  }

将活动类分成多个文件

0 个答案: