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androidxamarinfilewriter

Issue with filewriter under Xamarin Android

I am trying to write in a file with Xamarin Android. Here is my code:

 try
    {
    string r = (string)(DateFormat.Format("yyyy-MM-dd-hh-mm-ss", new Date()));
     string logFileBaseName = "drLog." + r; pause();


  mAccelLogFileWriter = new FileWriter(new File(STORAGE_DIR, logFileBaseName + ".accel.csv"));
  mStepLogFileWriter = new FileWriter(new File(STORAGE_DIR, logFileBaseName + ".steps.csv"));
  }
  catch (IOException e)
 {
 Log.Error(TAG, "Creating and opening log files failed!", e);
 e.PrintStackTrace();
   throw new RuntimeException(e);
 }

Knowing that I defined:

protected string STORAGE_DIR = SAMPLES_DIR + File.Separator + "dr";
 protected static readonly string SAMPLES_DIR = Android.OS.Environment.ExternalStorageDirectory + File.Separator + "samples_exp";

The problem is I get this exception when I create the file mAccelLogFileWriter. This exception says:

Java.Lang.RuntimeException: java.io.FileNotFoundException: /storage/emulated/0/samples_exp/dr/drLog.2016-07-21-09-22-59.accel.csv: open failed: ENOENT (No such file or directory)

When I debug the code I find for example that: SAMPLES_DIR="/storage/emulated/0/samples_exp" While I am trying to Get the External Storage Directory (SD Card).

Can you please tell me what is wrong with my code?

Solution

  • Use Java.IO.File.Mkdirs to make all the directories on your path before creating a Java.IO.FileWriter.

    Example:

    string SAMPLES_DIR = Path.Combine(Android.OS.Environment.ExternalStorageDirectory.ToString(), "samples_exp");
string STORAGE_DIR = Path.Combine(SAMPLES_DIR, "dr");
var r = DateFormat.Format("yyyy-MM-dd-hh-mm-ss", new Java.Util.Date());
var logFileBaseName = "drLog." + r;
// ~~~~
var storageDirs = new Java.IO.File(STORAGE_DIR);
storageDirs.Mkdirs();
// ~~~~
var mAccelLogFileWriter = new Java.IO.FileWriter(new Java.IO.File(STORAGE_DIR, logFileBaseName + ".accel.csv"));
var mStepLogFileWriter = new Java.IO.FileWriter(new Java.IO.File(STORAGE_DIR, logFileBaseName + ".steps.csv"));

    ADB output:

    adb shell ls -R  sdcard/samples_exp

sdcard/samples_exp:
dr

sdcard/samples_exp/dr:
drLog.2016-07-21-03-50-52.accel.csv
drLog.2016-07-21-03-50-52.steps.csv