在android应用中创建用户活动的日志报告

Question

I wan to make a log report of user activities in my android application i am creating a directory in android internal storage and also successfully creating a notepad file. I need to write log reports in different screens in 1st screen I am writing successfully and for 2nd time notepad file is becoming empty here is my code

File mydir,f;
FileWriter writer;
SimpleDateFormat df;
String formattedDate;
Calendar c = Calendar.getInstance();    
    SimpleDateFormat df = new SimpleDateFormat("E yyyy-MM-dd 'at' hh:mm:ss a ");
    formattedDate = df.format(c.getTime());
    mydir = getApplicationContext().getDir("LogFile",
            Context.MODE_PRIVATE); // Creating an internal dir;
    if (!mydir.exists()) {

        mydir.mkdirs();
    } else {
        // FileWriter fileWriter;
        try {
            f= new File(mydir, "kiran.txt");
            writer = new FileWriter(f);


        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
writer.append("User logged in at :"+formattedDate+"with     username="+username+" with password="+uPass+"\n");
writer.close();

Answer 1

Change method of FileWriter : writer = new FileWriter(f);

java.io.FileWriter.FileWriter(File file, boolean append) throws IOException

ie :

File logFile = new File(getFileName());
FileWriter file = new FileWriter(logFile, true);

true : Allow to appned

Answer 2

You need to open the file in append mode, Which can be achieved by using the FileWriter constructor.

Example

writer= new BufferedWriter(new FileWriter(your_file, true));

where true parameter of FileWriter is declaring that is your file will opening in append mode,