Develop Reference

file size not showing correct in android

I am using print writer and fileoutputstream to write a file in android async task using following function:
public static void saveFileToExternalMemoryAsync(Context context,String fileName, String json)throws Exception{
File AppPath = new File(Environment.getExternalStorageDirectory() + "/PDMA/DMAPPOutputs/");
if (!AppPath.exists()) {
AppPath.mkdirs();
}
File outputFile = new File(AppPath.getAbsolutePath() + "/" + fileName + ".dmapp");
if (!outputFile.exists())
outputFile.createNewFile();
MediaScannerConnection.scanFile(context, new String[] {AppPath.toString(),outputFile.toString()}, null, null);
FileOutputStream fileOutputStream = new FileOutputStream(outputFile, true);
PrintWriter pw = new PrintWriter(fileOutputStream);
try{
pw.println(json);
pw.flush();
pw.close();
fileOutputStream.flush();
fileOutputStream.close();
}catch (Exception e){
e.printStackTrace();
}finally{
pw.flush();
pw.close();
fileOutputStream.flush();
fileOutputStream.close();
MediaScannerConnection.scanFile(context, new String[] {AppPath.toString(),outputFile.toString()}, null, null);
}
}
problem is that when I try to copy this file by connecting mobile to pc in mtp, its not copied fully. If I right click to see its size, its less than actual. Now If in android, I copy and paste this file somewhere else, say in downloads folder, size is correct and file is also complete.
What can be the problem.
UPDATE:
If I use fileOutputStream to write bytes one by one , then file is generated but I have to close application to access this file from pc.

Well it turns out that by adding this.cancel(true) at the end of onPostExecute() solved problem in my case.

Android write text in file Sd card

i try to write text in file.i wrote code ,witch can to write text ,but if i will use again my code again text is rewrite in file.for example if i first time write "Hello android" and then "Sir",result is only "Sir".i want "Hello android Sir"
your_file = new File("/sdcard/facebookUser");
try {
Writer writer = new OutputStreamWriter(new FileOutputStream(
your_file), "UTF-8");
writer.write(facebook_user_name + ",");
writer.write(facebook_id);
writer.close();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (writer != null) {
try {
writer.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
how i can write code to save another text in this file second time?

new FileOutputStream(your_file, true)
public FileOutputStream(String name, boolean append) throws FileNotFoundException
append - if true, then bytes will be written to the end of the file rather than the beginning

Instead of:
writer = new OutputStreamWriter(new FileOutputStream(
your_file), "UTF-8");
Use:
writer = new OutputStreamWriter(new FileOutputStream(
your_file, true), "UTF-8");
This sets the FileOutputStream in append mode.
java.io.FileOutputStream.FileOutputStream(File file, boolean append)
throws FileNotFoundException
Constructs a new FileOutputStream that writes to file. If append is
true and the file already exists, it will be appended to; otherwise it
will be truncated. The file will be created if it does not exist.

try {
int n = 0;
String Name = "file";
File myFile = new File("/sdcard/test/");
if (!myFile.exists()) {
boolean b = myFile.mkdirs(); }
myFile = new File("/sdcard/test/"+Name+".txt");
while (myFile.exists())
{
myFile = new File("/sdcard/test/"+Name+n+".txt");
n++;
}
myFile.createNewFile();
FileOutputStream fOut = new FileOutputStream(myFile);
OutputStreamWriter myOutWriter = new OutputStreamWriter(fOut);
String str = "Your text to write";
myOutWriter.append(str);
myOutWriter.close();
fOut.close();
} catch (Exception e) {}
And do not forget permision:
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Vladimir Kulyk and user2450263 are correct! You have to write a file in append mode. try this link.

How to append data to text files in the new line, ( \n does not work)

I am using this code as a part to write data to a text file, but I am not sure how I can append the data to the new line. "\n" does not seem to be working. Here, variable "data" has this format:
t=1, x=-3.1, y=19.0, z=-8.6
this part of the code iterates and the variable "data" is written each time; the current result is something like:
t=1, x=-6.9, y=-9.6, z=-6.9t=2, x=-1.4, y=6.2, z=7.0t=3, x=-1.4, y=6.1, z=6.9t=4, and so on, but what I would like is:
t=1, x=-6.9, y=-9.6, z=-6.9
t=2, x=-1.4, y=6.2, z=7.0
t=3, x=-1.4, y=6.1, z=6.9
Thanks in advance for your help.
String datatest = data.toString();
File sdCard = Environment.getExternalStorageDirectory();
File directory = new File (sdCard.getAbsolutePath() + "/test");
directory.mkdirs();
String filename = "test.txt";
File file = new File(directory, filename);
FileOutputStream fOut = null;
try {
fOut = new FileOutputStream(file, true);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
OutputStreamWriter osw = new OutputStreamWriter(fOut);
try {
osw.write(datatest + "\n");
osw.flush();
osw.close();
} catch (IOException e) {
e.printStackTrace();
}

try "\r\n"
and to make this answer longer :)

Android: Can't find generated XML file

I am working on a method that writes an XML file to the device. I've allowed external storage in the manifest file, but I can't find the file at the location it should be.
Here is my code:
public static void write (){
Serializer serial = new Persister();
File sdcardFile = new File("/Prueba/file.xml");
Item respuestas = new Item();
try {
serial.write(respuestas, sdcardFile);
} catch (Exception e) {
// There is the possibility of error for a number of reasons. Handle this appropriately in your code
e.printStackTrace();
}
Log.i(TAG, "XML Written to File: " + sdcardFile.getAbsolutePath());
}
}

Sdcard File path problem. Here is an exaple that write string in file.xml file.
File myFile = new File("/sdcard/file.xml");
try {
File myFile = new File("/sdcard/file.xml");
myFile.createNewFile();
FileOutputStream fOut = new FileOutputStream(myFile);
OutputStreamWriter myOutWriter =
new OutputStreamWriter(fOut);
myOutWriter.append("encodedString");
myOutWriter.close();
fOut.close();
} catch (Exception e) {
}
You able to get External Storage name by this way,
String root = Environment.getExternalStorageDirectory().toString();

Android Emulator writes file but cannot find directory

I am trying to get a simple Hello World txt file to be written then read by my android application. When viewing the DDMS File Explorer it successfully creates the text file but i then get a FileNotFoundException when trying to read it.
try {
final String TESTSTRING = new String("Hello World");
FileOutputStream fOut = openFileOutput("test.txt", MODE_WORLD_READABLE);
OutputStreamWriter osw = new OutputStreamWriter(fOut);
osw.write(TESTSTRING);
osw.flush();
osw.close();
FileInputStream fIn = new FileInputStream("test.txt");
InputStreamReader isr = new InputStreamReader(fIn);
char[] inputBuffer = new char[TESTSTRING.length()];
isr.read(inputBuffer);
String readString = new String(inputBuffer);
boolean isTheSame = TESTSTRING.equals(readString);
Log.i("File Reading Stuff", "success = " + isTheSame);
} catch (IOException e) {
e.printStackTrace();
}
also the error is java.io FileNotFoundException: /test.txt (No such file or directory)
Any Help Thanks.

I don't know where openFileOutput saves its files, but wouldn't you use it's input equivalent openFileInput to read such a file?

See my previous post with information about how to read/write to the external storage directory in Android:
Android how to use Environment.getExternalStorageDirectory()
-- Dan