Develop Reference

Android : How to write into internal memory

I made this code to write on a sdcard, now how can I transform it to write into the internal memory ?
//private String path = Environment.getExternalStorageDirectory().getAbsolutePath() + "/liste.txt"; Path used to write on sdcard
try{
File file = new File(path);
BufferedWriter bw = new BufferedWriter(new FileWriter(file,true));
bw.write("something");
bw.flush();
bw.close();
catch(Exception e) {...}

In android each application has its own folder under /data/data/package/
this dir is only accessable by your app and the root if the device is rooted
to access this dir and read/write to it, you can use:
getApplicationContext().openFileOutput(name, mode);
and
getApplicationContext().openFileInput(name);
more about this here : Docs

USe this code:
FileOutputStream fos;
fos = context.openFileOutput(FILENAME, Context.MODE_WORLD_READABLE);
fos.write(data.getBytes()); //write to application top level directory for immediate sending
fos.close();

try{
File file = new File("/data/data/com.example.packagename/files/");
BufferedWriter bw = new BufferedWriter(new FileWriter(file,true));
bw.write("something");
bw.flush();
bw.close();
catch(Exception e) {...}
or
//To read file from internal phone memory
//get your application context:
Context context = getApplicationContext();
filePath = context.getFilesDir().getAbsolutePath();
File file = new File(filePath);

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);

how do i open a resource file for reading in Android

If I have a file in my resources (i.e. in res/raw for example), how do I open it for reading into an input stream? The file might be anything: a text file, a class seriaisation, etc.
On the PC I would use:
MyClass x = null;
FileInputStream fis = null;
ObjectInputStream ois = null;
fis = new FileInputStream("/home/me/Desktop/A.dat");
ois = new ObjectInputStream(fis);
x = (MyClass)ois.readObject();

You can open files from resources in the following way:
BufferedInputStream bis = new BufferedInputStream(getResources().openRawResource(R.raw.A));

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();

Serialize Object (jpg) to internal storage

I am trying to download a set of .jpg's from Amazon S3 and store them to the internal storage (so they can't be copied by a malicious user). I have gotten this far but now I am stuck. I have found multiple questions that deal with bitmaps or arrays but nothing about storing an image and then accessing it later. Anyone know where I go from here?
String itemName = iconNames.getString(iconNames.getColumnIndexOrThrow(DbAdapter.KEY_ICON));
itemName = itemName + ".jpg";
GetObjectRequest getObject = new GetObjectRequest(bucket, itemName);
S3Object icon = mS3Client.getObject(getObject);
InputStream input = icon.getObjectContent();
I have looked here in the dev guide and it gives the following code
http://developer.android.com/guide/topics/data/data-storage.html#filesInternal
String FILENAME = "hello_file";
String string = "hello world!";
FileOutputStream fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
fos.write(string.getBytes());
fos.close();
But this is for storing a string, not an image...

You have to copy InputStream to OutputStream. Something like this:
InputStream input = icon.getObjectContent();
FileOutputStream fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
// Transfer bytes from in to out
byte[] buf = new byte[1024];
int len;
while ((len = input.read(buf)) > 0) {
fos.write(buf, 0, len);
}
input.close();
fos.close();

You could do something like the following.
Bitmap bitmapPicture = someBitmap
String path = Environment.getExternalStorageDirectory().toString();
OutputStream fOut = null;
File file = new File(path, "tmp.png");
fOut = new FileOutputStream(file);
bitmapPicture.compress(Bitmap.CompressFormat.PNG, 100, fOut);
fOut.flush();
fOut.close();
MediaStore.Images.Media.insertImage(getContentResolver(),file.getAbsolutePath(),file.getName(),file.getName());