read text file method

Question

I am an android newby so apologies if this seems trivial, and the lengthy post. I have googled etc but the only android references I can find seem to refer to

InputStream is = getAssets().open("read_asset.txt");
        int size = is.available();

        // Read the entire asset into a local byte buffer.
        byte[] buffer = new byte[size];
        is.read(buffer);
        is.close();

I tried using this in my class but even after importing java.io.InputStream; it errored on the getAssets().

I am trying to use the rowId of a listview click to; open a text file (depends on rowId value), read the file line by line, generate a string array of the first 16 characters, etc then use the array to populate the next activity's listview.

String[] sectID = null; //to be loaded in listview
    switch (rowId){
        case 0://custom, go to section input screen
        case 1:                 
     readSectionFile s = new readSectionFile("Sect_US.dat");
     sectID=s.arrayShapesAll();

My readSectionFile class (extract) is;

public readSectionFile(String FileName) {
  //Count the number of section records in the data file
  String line = null;    // String that holds current file line
  int recordcount = 0;   // Line number of count
  try{
      BufferedReader buf = new BufferedReader(new FileReader(FileName));
      // Read file to count records
      while ((line = buf.readLine()) != null){    //null = EOF
          line = buf.readLine();
          if (line.substring(0, 1).equals("*") || line.length() == 0) {      //== comment or blank line
              //do nothing
          }else{
              recordcount++;
          }
      }//while
      buf.close();
  }catch (IOException x){
       x.printStackTrace();
  }//end try
  // Now read file to load array
  mSectionIDArray = new String[recordcount + 1];
  mSectionIdx = new int[recordcount + 1][2];
  mData = new double[recordcount + 1][15];
  int c=0;
  String sectdata = null;    // String that holds current file line
  try {
      BufferedReader buf = new BufferedReader(new FileReader(FileName));
      while ((sectdata = buf.readLine()) != null){           //null = EOF
          sectdata = buf.readLine();

The code doesn't work and crashes at readSectionFile s = new readSectionFile("Sect_US.dat");

also, in the readSectionFile code, the second instance of buf generates an Eclipse error asking for a try, catch block, whereas the first instance is accepted.

My questions are, Am I going about opening this text file (in /assets) correctly? What is wrong with the second buf use?

Answer 1

You wrote:

Am I going about opening this text file (in /assets) correctly?

One option is to place text files in a directory named raw under res, and read them into a String using openRawResource(...).

Assuming you have a text file called my_text_file in the raw directory,

String myText = readTextFileFromResource(context, R.raw.my_text_file);

where

private String readTextFileFromResource(Context context, int resourceId){
    StringBuilder fileContents = new StringBuilder();
    try{
        InputStream inputStream = context.getResources().openRawResource(resourceId);
        InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
        BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
        String nextLine;
        while((nextLine = bufferedReader.readLine()) != null){
            fileContents.append(nextLine);
            fileContents.append('\n');
        }
    }catch(IOException e){
        //handle
    }catch(Resources.NotFoundException nfe){
        //handle
    }
    return fileContents.toString();
}

Answer 2

getAssets() is a method in Activity. If you are trying to call getAssets() from a different class, pass an activity's context to the class where you want to call the method and then call context.getAssets().