Develop Reference

Unity 3D Android and File

I have a problem with Android and Unity 3D. I have a file read code. When I put my code on the computer, it works. However, my code does not work on Android (Mobile). How can I solve this problem? Thank you.
FileInfo theSourceFile = new FileInfo(filename);
if (System.IO.File.Exists(fname))
{
StreamReader reader = theSourceFile.OpenText();
string text = reader.ReadLine();
print(string);
}
EDIT updated code
string filename = "file.txt";
FileInfo theSourceFile = new FileInfo(filename);
filename = Application.persistentDataPath + "/"+filename;
System.IO.File.WriteAllText(filename,"Test");
if (System.IO.File.Exists(filename))
{
StreamReader reader = theSourceFile.OpenText();
string text = reader.ReadLine();
print(string);
}

You need to change your build settings for android Device.
Change Configuration >> write access to external (sd card).
if not, your app is pointing to internal path and you need root permission in your android device.

You must use Application.persistentDataPath on Android to be able to read anything.
Change that to string filename = Application.persistentDataPath + "/file.txt"; and your code should work fine.
Bear in mind that before the read function can work, you must write to the directory first. So file.txt must exist in Application.persistentDataPath first.
For example
string filename = Application.persistentDataPath + "/file.txt";
System.IO.File.WriteAllText(filename,"Test");
EDIT:
You new code is still not working because you had FileInfo theSourceFile = new FileInfo(filename); before filename = Application.persistentDataPath + "/"+filename;. This means that the file name is still not valid. Pay attention the order your script execute. After switching it, it worked on my Android. Below is the whole code.
string filename = "file.txt";
filename = Application.persistentDataPath + "/" + filename;
System.IO.FileInfo theSourceFile = new System.IO.FileInfo(filename);
System.IO.File.WriteAllText(filename, "Test");
if (System.IO.File.Exists(filename))
{
System.IO.StreamReader reader = theSourceFile.OpenText();
string text = reader.ReadLine();
print(text);
}

Not able to write to app specific directory in Android SD card

I learnt that from KitKat an application can only write to its specific directory.
But strangely i am not able to write into my specific application directory also.
Code to get the sd card directory
Process process = new ProcessBuilder().command("mount").start();
process.waitFor();
BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
String line;
while ((line = reader.readLine()) != null) {
// Output the line of output from the mount command
logger.debug(" {}", line);
if (line.startsWith("/dev/block/vold/")) {
String[] tokens = line.split(" ");
if (tokens.length >= 3 && (tokens[2].equals("vfat") || tokens[2].equals("exfat"))) {
String path = tokens[1];
File file = new File(path);
if (file.exists() && file.isDirectory()) {
logger.debug("Detected SD card at {}", file.getPath());
if (!file.canWrite()) {
logger.warn("The SD card path {} is reporting that it is not writable", file.getPath());
}
// path = basecontext.getExternalFilesDir(null).getPath();
return path;
}
}
}
}
Code to get a file
Here is how i construct the file path :
sdCardDirectory is the directory which i get like this: /storage/extSdCard/
directory and sub directory are my application sepcifc subdirectoryies but are obviously inside the app specific directory in the application
sdCardDirectory + File.separator + "Android" + File.separator + "data" + File.separator
+ <my app package> + File.separator + subdirectory
+ File.separator + directory+ File.separator + document.getRepositoryId() + FILENAME_SEPARATOR
+ fetchObjectId(document);
Where the ids retrieved are simple alpha numeric strings for e.g. aBc45ef_0
randomAccessFile = new RandomAccessFile(file, "rw");
I am getting
java.io.FileNotFoundException: /storage/extSdCard/Android/data/myapp/cache/downloaded/OhCQL_RQl8IJcVlO5T1MX4-3SQg_mMDT5PWtf-IYmE0: open failed: EROFS (Read-only file system)
Where myapp is the my application package name.
UPDATE This is the link to Android bug which i have opened https://code.google.com/p/android/issues/detail?id=69549&colspec=ID%20Type%20Status%20Owner%20Summary%20Stars
cheers,
Saurav

But strangely i am not able to write into my specific application directory also.
That code is not necessarily going to give you anything that you can use. Please use getExternalFilesDirs() (note the plural); the second and subsequent entries in the returned list will be from removable storage, where available.
You may wish to read my blog post on Android 4.4 and removable storage for more background.

Caching files using getCacheDir()

I wanted to download images that are downloaded from Dropbox and cache them for further use:
String cachePath = mContext.getCacheDir().getAbsolutePath() + entry.fileName();
File cacheFile = new File(cachePath);
//cacheFile.exists() returns true after 1st call
if(!cacheFile.exists()){
//If cache doesn't exist, download the file
mFos = new FileOutputStream(cachePath);
mApi.getThumbnail(path, mFos, ThumbSize.BESTFIT_320x240,
ThumbFormat.JPEG, null);
}
mDrawable = Drawable.createFromPath(cachePath);
mImageView.setImageDrawable(mDrawable);
The mDrawable is null if the code doesn't enter the if block.
If I comment the if condition it works fine. But downloads the images every time.
Edit:
The above code is from how to test for a file in cache

Try this hope helps you
String path = context.getFilesDir().getAbsolutePath() + File.separator + entry.fileName();
File file = new File(path);
if (file.exists()) {
// File exists
} else {
// File does not exist
}

Can't write to SD card

My app allows user to take a picture and I want that picture to be stored in the app's external files directory (getExternalFilesDir(null)). It all works except for the call to renameTo(), this call returns false and I don't know why.
The src file is:
/storage/extSdCard/DCIM/Camera/20140424_154458.jpg
Dest file is:
/storage/emulated/0/Android/data/com.myapp.myapp/files/20140424_154458.jpg
I also have specified the WRITE_EXTERNAL_STORAGE permission.
#Override
public boolean onOptionsItemSelected(MenuItem item)
{
if (item.getItemId() == R.id.action_take_picture)
{
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(intent, TAKE_PICTURE_REQUEST_CODE);
return true;
}
}
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data)
{
if (requestCode == TAKE_PICTURE_REQUEST_CODE && resultCode == RESULT_OK)
{
File dest = new File(
getExternalFilesDir(null),
new SimpleDateFormat("yyyyMMdd_hhmmss", Locale.getDefault()).format(new Date()) + ".jpg");
File src = new File(convertMediaUriToPath(data.getData()));
if (src.renameTo(dest)) // Always returns false
{
mAdapter.add(dest);
mAdapter.notifyDataSetChanged();
}
}
}
private String convertMediaUriToPath(Uri uri)
{
String[] proj = {MediaStore.Images.Media.DATA};
Cursor cursor = getContentResolver().query(uri, proj, null, null, null);
int column_index = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
cursor.moveToFirst();
String path = cursor.getString(column_index);
cursor.close();
return path;
}

I have ran into this problem previously - unfortunately, you are not allowed to use renameTo to move files and/or directories between different mount points (for example, internal and external storage). Consider using a different way of moving files, such as the one outlined here:
http://www.mkyong.com/java/how-to-copy-directory-in-java/
public static void copyFolder(File src, File dest) throws IOException{
if(src.isDirectory()){
//if directory not exists, create it
if(!dest.exists()){
dest.mkdir();
System.out.println("Directory copied from "
+ src + " to " + dest);
}
//list all the directory contents
String files[] = src.list();
for (String file : files) {
//construct the src and dest file structure
File srcFile = new File(src, file);
File destFile = new File(dest, file);
//recursive copy
copyFolder(srcFile,destFile);
}
}else{
//if file, then copy it
//Use bytes stream to support all file types
InputStream in = new FileInputStream(src);
OutputStream out = new FileOutputStream(dest);
byte[] buffer = new byte[1024];
int length;
//copy the file content in bytes
while ((length = in.read(buffer)) > 0){
out.write(buffer, 0, length);
}
in.close();
out.close();
System.out.println("File copied from " + src + " to " + dest);
}
}

The problem is with the method renameTo, the renameTo doesn't create subdirectories,
Reason being The current File API isn't very well implemented in Java. There is a lot of functionality that would be desirable in a File API that isn't currently present such as move, copy and retrieving file metadata.
I don't think anyone will be able to give you an answer as to why the API is written as is. Probably a poor first draft that went live and couldn't be changed due to backwards compatibility issues.
These issue have been addressed in the Java 7. A entirely new API has been created to deal with files java.nio.file.Files.
To Solve this issue, try to get directory path of destination file
e.g /storage/emulated/0/Android/data/com.myapp.myapp/files/20140424_154458.jpg
Destination Directory is
/storage/emulated/0/Android/data/com.myapp.myapp/files/
Use mkdirs() , it will create all sub directories for you

If you want to add a file or folder or move application into your SD Card just do the following:
steps:
1) Open your Android application's source code file with a text or programming editor. 2) Browse to the location in the source code where you wish to call the function that writes a file to the device's external storage. 3) Insert this single line of code to check for the SD card:
File sdCard = Environment.getExternalStorageDirectory();
4) Insert these lines of code to set the directory and file name:
File dir = new File (sdcard.getAbsolutePath() + "/folder1/folder2");
dir.mkdirs();
File file = new File(dir, "example_file");
// The mkdirs function will create the directory folder for you, use it only you want to create a new one.
5) Replace "/folder1/folder2" in the above code with the actual path where you intend to save the file. This should be a location in which you normally save your application files. Also, change the "example_file" value to the actual file name you wish to use.
6) Insert the following line of code to output the file to the SD card:
FileOutputStream f = new FileOutputStream(file);
Finally step 7:
Save the file, then compile it and test the application using the Android emulator software or the device.
This will work!!! ;-)

file.isDirectory() always false in android with the path

ANSWER:
Needed the call to getExternalFilesDir(p); like so:
String p = thepathblah;
File path=context.getExternalFilesDir(p);
EDIT EDIT:
While I knew the Environment.DIRECTORY_PICTURES was returning just Pictures/ I figured this worked because in android I assumed the file pointer was already pointing to your application space (sorta like in c#). So in this:
String p = Environment.DIRECTORY_PICTURES + "/" + s.getClient().getFirstName()+s.getClient().getLastName() +
"/" + s.getPackage().getName() +
(mSession.getSessionDate().getMonth()+1) +
mSession.getSessionDate().getDate() +
(mSession.getSessionDate().getYear()+1900);
I thought was getting the full path, in fact I was writing a file out to this with no issues. It turns out though to delete individual files (and load them) I needed a fuller path which ended up being:
String p = Environment.DIRECTORY_PICTURES + "/" + s.getClient().getFirstName()+s.getClient().getLastName() +
"/" + s.getPackage().getName() +
(mSession.getSessionDate().getMonth()+1) +
mSession.getSessionDate().getDate() +
(mSession.getSessionDate().getYear()+1900);
File dir = new File("/sdcard/Android/data/com.software.oursoftware/files/"+p);
Not sure if I can take it that the above link is valid for all Honeycomb devices or not, specifically the /sdcard/Android/data/packagespace/files/
Is this safe to use this or do I have to do something more dynamic for honeycomb devices???
EDIT: This is my little test function code to just write something to a folder...
String p = Environment.DIRECTORY_PICTURES + "/" + s.getClient().getFirstName()+s.getClient().getLastName() + "/" + s.getPackage().getName() + (mSession.getSessionDate().getMonth()+1) + mSession.getSessionDate().getDate() + (mSession.getSessionDate().getYear()+1900);
File path = mContext.getExternalFilesDir(p);
File file = new File(path, "DemoPicture.jpg");
try {
// Very simple code to copy a picture from the application's
// resource into the external file. Note that this code does
// no error checking, and assumes the picture is small (does not
// try to copy it in chunks). Note that if external storage is
// not currently mounted this will silently fail.
InputStream is = getResources().openRawResource(R.drawable.ic_contact_picture);
OutputStream os = new FileOutputStream(file);
byte[] data = new byte[is.available()];
is.read(data);
os.write(data);
is.close();
os.close();
// Tell the media scanner about the new file so that it is
// immediately available to the user.
MediaScannerConnection.scanFile(mContext,
new String[] { file.toString() }, null,
new MediaScannerConnection.OnScanCompletedListener() {
public void onScanCompleted(String arg0, Uri arg1) {
Log.i("ExternalStorage", "Scanned " + arg0 + ":");
Log.i("ExternalStorage", "-> uri=" + arg1);
}
});
} catch (IOException e) {
// Unable to create file, likely because external storage is
// not currently mounted.
Log.w("ExternalStorage", "Error writing " + file, e);
}
Then the way I try to delete this folder:
String p = Environment.DIRECTORY_PICTURES + "/" + firstName+lastName +"/" + pName+pDate;
File dir=new File(p);
deleteRecursive(dir);
results in
Pictures/ShaneThomas/Portrait882011/
Which can write a file, tested that, but if I try to say:
void deleteRecursive(File dir)
{
Log.d("DeleteRecursive", "DELETEPREVIOUS TOP" + dir.getPath());
if (dir.isDirectory())
{
String[] children = dir.list();
for (int i = 0; i < children.length; i++)
{
File temp = new File(dir, children[i]);
if(temp.isDirectory())
{
Log.d("DeleteRecursive", "Recursive Call" + temp.getPath());
deleteRecursive(temp);
}
else
{
Log.d("DeleteRecursive", "Delete File" + temp.getPath());
boolean b = temp.delete();
if(b == false)
{
Log.d("DeleteRecursive", "DELETE FAIL");
}
}
}
dir.delete();
}
}
The dir.isDirectory is always false!? I got this delete file/directories code off stack overflow but am puzzled as to why its not working?
and I do have this set:
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

There are several reasons for File.isDirectory() to return false:
The path points to file (obviously), and not to directory.
The path is invalid (i.e. there is no such file/directory exists).
There is not enough permissions granted to your application to determine whether path points to directory.
In general, if isDirectory() returns true, you've got path that points to directory. But if isDirectory() returns false, then it might be or might not be a directory.
In your particular case, the path most likely does not exist. You need to call dir.mkdirs() to create all directories in the path. But since you need that to only recursively delete them, then there is no point in calling dir.mkdirs() just to remove that directory after that.

I think you want to add
dir.mkdirs() right after File dir=new File(p). mkdirs() is the method responsible for actually creating a directory, not new File().

Ok it's answered, but sometimes the issue fires because of sample reasone:permission :
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
if you forgot this permission you will always get false result.