CODEWITHSUNDEEP
androidloggingandroid-sdcard
Rori Stumpf
Rori Stumpf

Reputation: 1977

Empty Android log file using FileHandler()

I'm trying to set up a log handler to output the Android log to file to external storage. The code below creates the log file, but no output is sent to the file, so something is obviously wrong with how the handler is configured. Or, perhaps this arrangement cannot be expected to work at all?

The function is called in onCreate() from the main activity.

private void logToFile(String path) {
    try {

        // Get package name 
        String packageName = MainActivity.class.getPackage().getName();         
        String logfileName = path + "/" + packageName + ".log";         

        Logger logger = Logger.getLogger(packageName);
        logger.setLevel(Level.FINE);

        FileHandler fileTxt = new FileHandler(logfileName);

        SimpleFormatter formatterTxt = new SimpleFormatter();
        fileTxt.setFormatter(formatterTxt);

        logger.addHandler(fileTxt);

        Toast.makeText(this, "Logging to " + logfileName, Toast.LENGTH_LONG).show();

    } catch (IOException e) {
        Log.d(TAG, e.getMessage());
    }
    Log.i(TAG, "logging to filesystem enabled");
}

Upvotes: 0

Views: 1413

Answers (2)

LordParsley
LordParsley

Reputation: 4048

I was frustrated at having to use Logger instead of standard Logcat Log.d(), Log.e(), etc. so I started using this Frankenstein's monster solution of reading from Logcat into a LogRecord and saving that using FileHandler.

This means you can limit the log file size easily, and retain your detailed Android logs.

But this isn't going to give you continuous output to file. If you don't mind pressing a button or calling it once a session though, then it shouldn't really matter since Logcat is constantly updated anyway.

(I strongly recommend calling from a non-UI thread.)

FileHandler fh=null;
String name;
if ( 0 == Environment.getExternalStorageState().compareTo(Environment.MEDIA_MOUNTED))
    name = Environment.getExternalStorageDirectory().getAbsolutePath();
else
    name = Environment.getDataDirectory().getAbsolutePath();
name += "/yourapp/yourapp";

try {
    fh = new FileHandler(name, 1024*1024, 7, true); //Limit to 7 x 1MB files.
    fh.setFormatter(new SimpleFormatter());

    //Try to read Logcat.
        try {
            //Dumps the entire logcat to std output.
            Process processD = Runtime.getRuntime().exec("logcat -v long -d");
            BufferedReader bufferedReaderD = new BufferedReader(new InputStreamReader(processD.getInputStream()));  

            String lineD;  
            while ((lineD = bufferedReaderD.readLine()) != null){  
                //Send to the file handler.
                fh.publish(new LogRecord(Level.ALL, lineD)); 
            }

            //Clear the logcat storage. Don't feel like rewriting old records.
            Process processC = Runtime.getRuntime().exec("logcat -c");

    } catch (IOException e) {  
        Log.e(TAG, "Could not get Logcat logs.");
        e.printStackTrace();
    }

} catch (Exception e) {

    Log.e("MyLog", "FileHandler exception", e);

} finally {
    if (fh != null)
         fh.close();
}

Upvotes: 0

Rori Stumpf
Rori Stumpf

Reputation: 1977

To write to the logger declared above (and, thus, the attached handler which writes to a file), the following should be used instead of Log.i(TAG, "message")

private static final Logger logger = Logger.getLogger(TAG); 

public void someFunction() {
    logger.info("message")
}

These log messages will also appear in logCat/debugger, with the supplied TAG. P.S. Java logging makes my head hurt...

Upvotes: 1

Related Questions