OutputStreamWriter does not append

问题:

Original code and its working saving the data to the SD Card

// Writing data to internal storage
btnSaveData.setOnClickListener(new View.OnClickListener() {

 @Override
 public void onClick(View v) {
   if (isSDCardWritable()) {
      String dataToSave = etData.getText().toString();
         try {
         // SD Card Storage
         File sdCard = Environment.getExternalStorageDirectory();
         File directory = new File(sdCard.getAbsolutePath()+"/MyFiles");
         directory.mkdirs();
         File file = new File(directory, "text.txt");
         FileOutputStream fos = new FileOutputStream(file);
         OutputStreamWriter osw = new OutputStreamWriter(fos);

         // write the string to the file
         osw.write(dataToSave);
         osw.flush();
         osw.close();
         . . . 

And then I changed the code to append a new values as it should be according to what I need:

            osw.append(dataToSave);
            osw.flush();
            osw.close();

Problem is: It overwrites the text file instead of appending. What did I miss? Thanks for helping

回答1:

Constructor FileOutputStream( File file ) always overwrites file. If you want to append to file you have to use more generic constructor FileOutputStream( File file, boolean append ). If you set parameter 'append' to true file is not overwritten.