Saving Sequential data in Java

Question

I have some problems about saving sequential data (Contour Area), I have a project that detect contour. And I want to save data contour area in my android. I already save that contour area in file, but its just the last one, not a sequential data(all contour area) . here's my contour code:

Imgproc.findContours(mDilated, contours, hierarchy, Imgproc.RETR_TREE, Imgproc.CHAIN_APPROX_SIMPLE);
int a =15;
float b = (float)4.55;
double maxVal = 0;
int maxValIdx = 0;
for ( int contourIdx=0; contourIdx < contours.size(); contourIdx++ ) {
    double contourArea = Imgproc.contourArea(contours.get(contourIdx));
    if (maxVal < contourArea) {
        maxVal = contourArea;
        maxValIdx = contourIdx;
    }

Here's my code for saving file:

String taString = Integer.toString(a)+","+Float.toString(b)+","+Double.toString(maxVal);
writeToFile(taString);

and this the writeToFile function :

private void writeToFile(String data) {
    try {
        File sdCard = Environment.getExternalStorageDirectory();
        File directory = new File (sdCard.getAbsolutePath() + "/MyFiles");
        directory.mkdirs();

        File file = new File(directory, "mysdfile.txt");
        FileOutputStream fOut = new FileOutputStream(file);
        OutputStreamWriter osw = new OutputStreamWriter(fOut);
        osw.write(data);
        osw.close();
    }
    catch (IOException e) {
        Log.e("Exception", "File write failed: " + e.toString());
    }

then when I'm open my file (msydfile.txt) its just contains a,b,contour area (like : 15, 4.55, 8418) ..But i want to save others contour area like sequential data.

Hopefully, someone has some experience in this. Thanks..

@MartinFrank of course yes, i want to save my contour area Log in my file.. — Bagus W, Oct 25 '16 at 04:43
You may have a look at http://stackoverflow.com/questions/1625234/how-to-append-text-to-an-existing-file-in-java — ZdaR, Oct 25 '16 at 04:50

score 0 · Accepted Answer · answered Oct 25 '16 at 04:49

0

if you want to append your data you have to tell the OutputStream to do so:

boolean append = true;
FileOutputStream fOut = new FileOutputStream(file, append);

see FileOutputStream for further explanation.

answered Oct 25 '16 at 04:49

Martin Frank

3,445
1
27
47

Saving Sequential data in Java

1 Answers1