Question

I am trying to develop apps for Android and I don’t know how to write/read a file in Android phone.

Normally I would do the following:

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileReader;
import java.io.FileWriter;

public class Test {

    public static void main(String[] args) {
        try {
            String path = "file.txt";
            BufferedWriter bw = new BufferedWriter(new FileWriter(path));
            bw.write("XYZ");
            bw.close();

            BufferedReader br = new BufferedReader(new FileReader(path));
            String line = "", data = "";
            while ((line = br.readLine()) != null) {
                data = data + line;
            }
            br.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

Answer 1

You’re pretty close. Here is something that I did, where I check to see if there is an SD card, if not it will save it locally (remember, since it is an Android app, all your data will be saved on the phone), then you create a directory if there isn’t one and then write to file. Let me know if you have any questions. This is more for writing, but reading is just as simple, you simply create a buffered reader, give it the file, and read; much like you have done in your code.

I hope this helps:

SimpleDateFormat photoFormat = new SimpleDateFormat("ddMMyy-hhmmss");

        // create formating for date
        SimpleDateFormat sdf = new SimpleDateFormat("MMMddyy-hhmmss");
        /*
         * This sections checks the phone to see if there is a SD card. if
         * there is an SD card, a directory is created on the SD card to
         * store the test log results. If there is not a SD card, then the
         * directory is created on the phones internal hard drive
         */
        // if there is no SD card
        if (Environment.getExternalStorageState() == null) {
            directory = new File(Environment.getDataDirectory()
                    + "/RobotiumTestLog/");
            photoDirectory = new File(Environment.getDataDirectory()
                    + "/Robotium-Screenshots/");

            // if no directory exists, create new directory
            if (!directory.exists()) {
                directory.mkdir();
            }

            // if phone DOES have sd card
        } else if (Environment.getExternalStorageState() != null) {
            // search for directory on SD card
            directory = new File(Environment.getExternalStorageDirectory()
                    + "/RobotiumTestLog/");
            photoDirectory = new File(
                    Environment.getExternalStorageDirectory()
                            + "/Robotium-Screenshots/");

            // if no directory exists, create new directory to store test
            // results
            if (!directory.exists()) {
                directory.mkdir();
            }
        }// end of SD card checking

        /*
         * Below is where the name of the test log is created.This can be
         * changed for any other test methods
         */
        String fileName = "TravelTestResults.csv";

        /*
         * Checks for existing test logs, and if they exist, they are
         * deleted, creating a new test log for each testing method
         */
        File logResults = new File(directory, fileName);
        if (logResults.exists()) {
            logResults.delete();
        }
        if (!logResults.exists()) {
            logResults.createNewFile();
        }
        /*
         * This creates the writing stream to log the test results This
         * stream MUST be closed, using bw.close(), for the test results to
         * show on the log. If the stream is not closed, when you open the
         * text file that the results are stored in, the page will be blank.
         */
        bw = new BufferedWriter(new FileWriter(logResults, true));
        bw.write("Test Run, Test Result, Comments \"\n\"");
                    bw.close();