Develop Reference

Creating File With String Object

im writing a socket program which send and receive strings.
Im trying to build a file using this received strings that are sending from other side.
this is exactly done with text files but in others such an image file doesn't work and when complete, the image does not open!
in receiver:
file = new File(dir,FileName);
fOut = new FileOutputStream(file);
dos = new DataOutputStream(fOut);
and when a msg received:
dos.write(msg.getBytes("UTF-8"));
in sender:
File file = new File(FilePath);
InputStream is = new FileInputStream(file);
InputStreamReader isr = new InputStreamReader(is);
...
isr.read(inputBuffer);
I have Tried this solution but the problem didn't fixed:
Changing the UTF-8 to ISO-8859-1
using output stream writer instead of data output stream.
trying with smaller pictures than text file.

ByteArrayOutputStream is useful converting bitmap to byte array.
after then, you using BitmapFactory, decodeByteArray is converting byte to bitmap.

how to read/write data dictionary in android programmatically

I want to read/write data dictionary in file which is in android internal/external memory. In WP7, they have used IsolatedStorage for storing the dictionary directly. In IOS, they can write NSDictionary directly to the file. Please anyone tell me the way to write DataDictionary into file.
Note: I have the keys and values in the Map variable.
how to store this Map directly to file

I would suggest putting your words into a database for the following reasons
DB lookups on android with SQLite are "fast enough" (~1ms) for even
the most impatient of users
Reading large files into memory is a dangerous practice in
memory-limited environments such as android.
Trying to read entries out of a file "in place" rather than "in
memory" is effectively trying to solve all the problems that SQLite
already solves for you.
Embed a database in the .apk of a distributed application [Android]
You can find more detailed examples by searching object serialization
[EDIT 1]
Map map = new HashMap();
map.put("1",new Integer(1));
map.put("2",new Integer(2));
map.put("3",new Integer(3));
FileOutputStream fos = new FileOutputStream("map.ser");
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(map);
oos.close();
FileInputStream fis = new FileInputStream("map.ser");
ObjectInputStream ois = new ObjectInputStream(fis);
Map anotherMap = (Map) ois.readObject();
ois.close();
System.out.println(anotherMap);
[EDIT 2]
try {
File file = new File(getFilesDir() + "/map.ser");
Map map = new HashMap();
map.put("1", new Integer(1));
map.put("2", new Integer(2));
map.put("3", new Integer(3));
Map anotherMap = null;
if (!file.exists()) {
FileOutputStream fos = new FileOutputStream(file);
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(map);
oos.close();
System.out.println("added");
} else {
FileInputStream fis = new FileInputStream(file);
ObjectInputStream ois = new ObjectInputStream(fis);
anotherMap = (Map) ois.readObject();
ois.close();
System.out.println(anotherMap);
}
} catch (Exception e) {
}
[EDIT 3]
Iterator myVeryOwnIterator = meMap.keySet().iterator();
while(myVeryOwnIterator.hasNext()) {
String key=(String)myVeryOwnIterator.next();
String value=(String)meMap.get(key);
// check for value
}

I'm unsure if using SharedPreferences (link) is something that is suitable for your usecase.
You store via a key-value pair, and can have multiple SharedPreferences per application. While both are stored as String objects, the value can be automatically cast to other primitives using built in methods.
Mark Murphy has written a library, cwac-loaderex (link), to facilitate access of SharedPreferences via the use of the Loader pattern (link), which offsets some of the work you need to do to keep IO off the main thread.

Saving a string serialized and buffered android JAVA.IO ObjectInputStream

I am saving out and loading mixed data types. I either have the saving part wrong or the loading part wrong. I am using buffered serial save and load method.
Variable lastFetchDate is defined as a string and initialized as "00/00/00".
It throws an error when reloading the data after it has been saved. What is wrong? I would have thought the opposite to writeBytes would be readBytes for a string.
Saving is as follows:
FileOutputStream fos = new FileOutputStream("userPrefs.dat");
BufferedOutputStream bos = new BufferedOutputStream(fos);
ObjectOutputStream oos = new ObjectOutputStream(bos);
oos.writeBytes(lastFetchDate);
// I close all streams
Loading is as follows:
FileInputStream fis = new FileInputStream("userPrefs.dat");
BufferedInputStream bis = new BufferedInputStream(fis);
ObjectInputStream ois = new ObjectInputStream(bis);
lastFetchDate=(String)ois.readObject(); //<<<<< Error thrown here
// I close all streams

You have written string as byte[] so need to read as byte[]
byte [] bString = new byte[lastFetchDate.length()*2];
ois.readFully(bString, 0, bString.length);
Or if you write as Object using writeObject method then you can read as object,
oos.writeObject(lastFetchDate);

Android: Write and Get Object

I want to write a serializable object to file in internal memory. Then, I want to load that object back from that file later. How could I do this in Android?

First of all your object must implement Serializable. Don't forget to add a serialVersionUID on the serializable class.
Then if you don't want to save specific field of the object mark it as transient.
Be sure all fields are serializable.
Next create a file in the internal memory and create an ObjectOutputStream to save your object. If you want to save in a specific folder you can create a path like this:
File path=new File(getFilesDir(),"myobjects");
path.mkdir();
Then you can use that path to save your object:
File filePath =new File(path, "filename");
FileOutputStream fos = new FileOutputStream(filePath);
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(object);
oos.close();
Reading is similar:
FileInputStream fis = new FileInputStream(file);
ObjectInputStream in = new ObjectInputStream(fis);
MyObjectClass myObject = (MyObjectClass ) in.readObject();
in.close();

Trying to figure out how to write an array out to a file stream in Android

In my app on the simulator it takes like 20 secs to save a file 48k long. Right now I'm saving byte by byte. Using a file stream, FileOutputStream write function.
Which looks like fos.write(cGlobals.board.BitMap[c++]);
I tried to do this but got a compile error saying invalid parm
fos.write(cGlobals.board.BitMap);
Is there a better way of doing this then byte by byte?
Ted

Make a BufferredOutputStream around your FileOutputStream
FileOutputStream fileOutputStream = new FileOutputStream(.....);
OutputStream bos = new BufferedOutputStream(fileOutputStream, 8192);
try {
... do your stuff using bos instead of fileOutputStream
} finally {
bos.close();
}