use code below. Please note, all objects fields should be Serializable.
Types like String, int, HashMap... are already serializable, but if you create a class of your own, you should verify that that it implements Serializable, and so all of his content recursively.
Write to file:
/**
* Writes Serializable object into a file
*/
public static void writeObjectToFile(Context context, Object object, String filename)
{
ObjectOutputStream objectOut = null;
try
{
FileOutputStream fileOut = context.openFileOutput(filename,Activity.MODE_PRIVATE);
objectOut = new ObjectOutputStream(fileOut);
objectOut.writeObject(object);
fileOut.getFD().sync();
}
catch (IOException e)
{
e.printStackTrace();
}
finally
{
if (objectOut != null)
{
try
{
objectOut.close();
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
}
Read from file:
/**
* Reads a Serializable object from a file
*/
public static Object readObjectFromFile(Context context, String filename)
{
ObjectInputStream objectIn = null;
Object object = null;
try
{
FileInputStream fileIn = context.getApplicationContext().openFileInput(filename);
objectIn = new ObjectInputStream(fileIn);
object = objectIn.readObject();
}
catch (FileNotFoundException e)
{
// Do nothing
}
catch (IOException e)
{
e.printStackTrace();
}
catch (ClassNotFoundException e)
{
e.printStackTrace();
}
finally
{
if (objectIn != null)
{
try
{
objectIn.close();
}
catch (IOException e)
{
e.printStackTrace();
}
}
}
return object;
}
