Develop Reference

How to load a file from assets folder of my android test project?

Is there a way to get the file object of one of the files which are inside the assets folder. I know how to load the inputstream of such a file, but i need to have a file object instead of the inputstream.
This way i load the inputstream
InputStream in2 = getInstrumentation().getContext().getResources().getAssets().open("example.stf2");
But I need the file object, this way the file will not be found
File f = new File("assets/example.stf2");

Found a soltion which works in my case, mabye someone else can use this as well.
Retrieving the file from my android test project to an inputstream
InputStream input = getInstrumentation().getContext().getResources().getAssets().open("example.stf2");
Create a file on the External-Cachedir of the android application under test
File f = new File(getInstrumentation().getTargetContext().getExternalCacheDir() +"/test.txt");
Copy the inputstream to the new file
FileUtils.copyInputStreamToFile(input, f);
Now I can use this file for my further tests

try below code:-
AssetManager am = getAssets();
InputStream inputStream = am.open(file:///android_asset/myfoldername/myfilename);
File file = createFileFromInputStream(inputStream);
private File createFileFromInputStream(InputStream inputStream) {
try{
File f = new File(my_file_name);
OutputStream outputStream = new FileOutputStream(f);
byte buffer[] = new byte[1024];
int length = 0;
while((length=inputStream.read(buffer)) > 0) {
outputStream.write(buffer,0,length);
}
outputStream.close();
inputStream.close();
return f;
}catch (IOException e) {
//Logging exception
}
return null;
}
for more info see below link :-
How to pass a file path which is in assets folder to File(String path)?

File copying: what am I doing wrong?

Sorry,
I have no experience with the Android file system, I am struggling to understand it via the documentation and the tutorials.
I am trying to copy a file from a location to the external storage of my app.
final File filetobecopied =item.getFile();
File path=getPrivateExternalStorageDir(mContext);
final File destination = new File(path,item.getName());
try
{copy(filetobecopied,destination);
}
catch (IOException e) {Log.e("",e.toString());}
public void copy(File src, File dst) throws IOException {
InputStream in = new FileInputStream(src);
OutputStream out = new FileOutputStream(dst);
// Transfer bytes from in to out
byte[] buf = new byte[1024];
int len;
while ((len = in.read(buf)) > 0) {
out.write(buf, 0, len);
}
in.close();
out.close();
Toast.makeText(mContext,"COPIED",Toast.LENGTH_SHORT).show();
}
public File getPrivateExternalStorageDir(Context context) {
File file = context.getExternalFilesDir(null);
if (!file.mkdirs()) {
Log.e("", "Directory not created");
}
return file;
}
I get the following error:
09-18 10:14:04.260: E/(7089): java.io.FileNotFoundException: /storage/emulated/0/Android/data/org.openintents.filemanager/files/2013-08-24 13.18.14.jpg: open failed: EISDIR (Is a directory)

http://developer.android.com/reference/android/content/Context.html#getExternalFilesDir(java.lang.String) use this example of code and use standart examples of google)

Try
final File destination = new File(path + "/" + item.getName());
instead.

I assume, folder directory is not created or your external storage state is not mounted.
Before you perform file operations, you should sanitize your path. Following code is a sample code that I often use.
public File sanitizePath(Context context) {
String state = android.os.Environment.getExternalStorageState();
File folder = null;
if (!state.equals(android.os.Environment.MEDIA_MOUNTED)) {
folder = new File(context.getFilesDir() + path);
// path is the desired location that must be specified in your code.
}else{
folder = new File(Environment.getExternalStorageDirectory().getAbsolutePath() + path);
}
if (!folder.exists()){
folder.mkdirs();
}
return folder;
}
And be sure about that, when your directory has to be created before you perform file operations.
Hope this will help.
EDIT: By the way, you have to add following permission to your manifest.xml file
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

Android: how do I create File object from asset file?

I have a text file in the assets folder that I need to turn into a File object (not into InputStream). When I tried this, I got "no such file" exception:
String path = "file:///android_asset/datafile.txt";
URL url = new URL(path);
File file = new File(url.toURI()); // Get exception here
Can I modify this to get it to work?
By the way, I sort of tried to "code by example" looking at the following piece of code elsewhere in my project that references an HTML file in the assets folder
public static Dialog doDialog(final Context context) {
WebView wv = new WebView(context);
wv.loadUrl("file:///android_asset/help/index.html");
I do admit that I don't fully understand the above mechanism so it's possible that what I am trying to do can't work.
Thx!

You cannot get a File object directly from an asset, because the asset is not stored as a file. You will need to copy the asset to a file, then get a File object on your copy.

You cannot get a File object directly from an asset.
First, get an inputStream from your asset using for example AssetManager#open
Then copy the inputStream :
public static void writeBytesToFile(InputStream is, File file) throws IOException{
FileOutputStream fos = null;
try {
byte[] data = new byte[2048];
int nbread = 0;
fos = new FileOutputStream(file);
while((nbread=is.read(data))>-1){
fos.write(data,0,nbread);
}
}
catch (Exception ex) {
logger.error("Exception",ex);
}
finally{
if (fos!=null){
fos.close();
}
}
}

Contrary to what others say, you can obtain a File object from an asset as follows:
File myAsset = new File("android.resource://com.mycompany.app/assets/my-asset.txt");

This function missing in code. #wadali
private void copyFile(InputStream in, OutputStream out) throws IOException {
byte[] buffer = new byte[1024];
int read;
while((read = in.read(buffer)) != -1){
out.write(buffer, 0, read);
}
}
Source: https://stackoverflow.com/a/4530294/4933464

what is the folder of sdcard and how can i create files and read and write them in it

please somebody tell me what is the folder of sdcard and how can i create files in it.because i am new to android and i have googled so much but could not find any comprehensive stuff.i want to create file in sdcard manually. please help.
here is my code i have written but now it says fileNotFoundException. hence i have created a file in sdcard but still it is not recognisizing the file.any suggestions please.
try
{
String root = android.os.Environment.getExternalStorageDirectory().getPath();
File gpxfile = new File(root, "sijjeel.txt");
//FileWriter writer = new FileWriter(gpxfile);
FileOutputStream writer = new FileOutputStream(gpxfile);
writer.write(bArray, 0, bArray.length);
writer.flush();
writer.close();
}
thanks alot

Path to sdcard is:
android.os.Environment.getExternalStorageDirectory().getPath()
To write a file, you can use the regular java.io.File methods for that.
For example, for creating a text files I use a helper method like this:
/**
* Stores text content into a file
* #param filename Path to the output file
* #param content Content to be stored in file
* #throws IOException
*/
public void storeFile(final String filename, final String content, String charSet)
throws IOException {
if (charSet==null) charSet = "utf-8";
Writer w = new OutputStreamWriter( new FileOutputStream(filename), charSet );
w.write(content);
w.flush();
w.close();
}
public void storeFile(final String filename, final String content)
throws IOException {
storeFile(filename, content, null);
}
or copying a file to sdcard:
public static final void copyfile(String srFile, String dtFile){
try{
File f1 = new File(srFile);
File f2 = new File(dtFile);
InputStream in = new FileInputStream(f1);
OutputStream out = new FileOutputStream(f2);
byte[] buf = new byte[1024];
int len;
while ((len = in.read(buf)) > 0){
out.write(buf, 0, len);
}
in.close();
out.close();
System.out.println("File copied to " + f2.getAbsolutePath());
} catch(FileNotFoundException ex){
System.out.println(ex.getMessage() + " in the specified directory.");
System.exit(0);
} catch(IOException e){
System.out.println(e.getMessage());
}
}

It's /sdcard (if you actually have a card in it)

The code you provided will create the file if it is not already there. Make sure you run your program on the emulator that has an SD card mounted. If it doesn't you can see an icon in the notification area saying so.

Load files bigger than 1M from assets folder

I'm going crazy, I created a file object, so it can be read with ObjectInputStream, and I placed the assets folder.
The method works with a file smaller than 1M, and give error with larger files.
I read that is a limit of Android platform, but I also know that can be "easily" avoided.
Those who have downloaded the game Reging Thunder, for example, can easily see that in their assets folder is a file 18.9M large.
This is my code for read 1 object from a ObjecInputStream
File f = File.createTempFile("mytempfile", "dat");
FileOutputStream fos = new FileOutputStream(f);
InputStream is = mc.getAssets().open(path,3);
ObjectInputStream ois=new ObjectInputStream(is);
byte[] data = (byte[]) ois.readObject();
fos.write(data);
fos.flush();
fos.close();
ois.close();
is.close();
now I have an uncompressed file and I can use it without worrying about the error "This file can not be opened as a file descriptor; it is probably compressed"
This function works well with files smaller than 1M, with bigger files return an
java.io.IOException on line "ObjectInputStream ois=new ObjectInputStream(is);"
why??

Faced the same issue. I've cut up my 4MB file into 1 MB chunks, and on the first run I join the chunks into a data folder on the phone. As an added bonus, the APK is properly compressed. The chunk files are called 1.db, 2.db, etc. The code goes like this:
File Path = Ctxt.getDir("Data", 0);
File DBFile = new File(Path, "database.db");
if(!DBFile.exists() || DatabaseNeedsUpgrade) //Need to copy...
CopyDatabase(Ctxt, DBFile);
static private void CopyDatabase(Context Ctxt, File DBFile) throws IOException
{
AssetManager assets = Ctxt.getAssets();
OutputStream outstream = new FileOutputStream(DBFile);
DBFile.createNewFile();
byte []b = new byte[1024];
int i, r;
String []assetfiles = assets.list("");
Arrays.sort(assetfiles);
for(i=1;i<10;i++) //I have definitely less than 10 files; you might have more
{
String partname = String.format("%d.db", i);
if(Arrays.binarySearch(assetfiles, partname) < 0) //No such file in assets - time to quit the loop
break;
InputStream instream = assets.open(partname);
while((r = instream.read(b)) != -1)
outstream.write(b, 0, r);
instream.close();
}
outstream.close();
}

The limitation is on compressed assets. If the asset is uncompressed, the system can memory-map the file data and use the Linux virtual memory paging system to pull in or discard 4K chunks as appropriate. (The "zipalign" tool ensures that uncompressed assets are word-aligned in the file, which means they'll also be aligned in memory when directly mapped.)
If the asset is compressed, the system has to uncompress the entire thing to memory. If you have a 20MB asset, that means 20MB of physical memory is tied up by your application.
Ideally the system would employ some sort of windowed compression, so that only parts need to be present, but that requires some fanciness in the asset API and a compression scheme that works well with random access. Right now APK == Zip with "deflate" compression, so that's not practical.
You can keep your assets uncompressed by giving them a suffix of a file type that doesn't get compressed (e.g. ".png" or ".mp3"). You may also be able to add them manually during the build process with "zip -0" instead of having them bundled up by aapt. This will likely increase the size of your APK.

Like Seva suggested you can split up your file in chunks. I used this to split up my 4MB file
public static void main(String[] args) throws Exception {
String base = "tracks";
String ext = ".dat";
int split = 1024 * 1024;
byte[] buf = new byte[1024];
int chunkNo = 1;
File inFile = new File(base + ext);
FileInputStream fis = new FileInputStream(inFile);
while (true) {
FileOutputStream fos = new FileOutputStream(new File(base + chunkNo + ext));
for (int i = 0; i < split / buf.length; i++) {
int read = fis.read(buf);
fos.write(buf, 0, read);
if (read < buf.length) {
fis.close();
fos.close();
return;
}
}
fos.close();
chunkNo++;
}
}
If you do not need to combine the files into a single file on the device again, just use this InputStream, which combines them into one on the fly.
import java.io.IOException;
import java.io.InputStream;
import android.content.res.AssetManager;
public class SplitFileInputStream extends InputStream {
private String baseName;
private String ext;
private AssetManager am;
private int numberOfChunks;
private int currentChunk = 1;
private InputStream currentIs = null;
public SplitFileInputStream(String baseName, String ext, int numberOfChunks, AssetManager am) throws IOException {
this.baseName = baseName;
this.am = am;
this.numberOfChunks = numberOfChunks;
this.ext = ext;
currentIs = am.open(baseName + currentChunk + ext, AssetManager.ACCESS_STREAMING);
}
#Override
public int read() throws IOException {
int read = currentIs.read();
if (read == -1 && currentChunk < numberOfChunks) {
currentIs.close();
currentIs = am.open(baseName + ++currentChunk + ext, AssetManager.ACCESS_STREAMING);
return read();
}
return read;
}
#Override
public int available() throws IOException {
return currentIs.available();
}
#Override
public void close() throws IOException {
currentIs.close();
}
#Override
public void mark(int readlimit) {
throw new UnsupportedOperationException();
}
#Override
public boolean markSupported() {
return false;
}
#Override
public int read(byte[] b, int offset, int length) throws IOException {
int read = currentIs.read(b, offset, length);
if (read < length && currentChunk < numberOfChunks) {
currentIs.close();
currentIs = am.open(baseName + ++currentChunk + ext, AssetManager.ACCESS_STREAMING);
read += read(b, offset + read, length - read);
}
return read;
}
#Override
public int read(byte[] b) throws IOException {
return read(b, 0, b.length);
}
#Override
public synchronized void reset() throws IOException {
if (currentChunk == 1) {
currentIs.reset();
} else {
currentIs.close();
currentIs = am.open(baseName + currentChunk + ext, AssetManager.ACCESS_STREAMING);
currentChunk = 1;
}
}
#Override
public long skip(long n) throws IOException {
long skipped = currentIs.skip(n);
if (skipped < n && currentChunk < numberOfChunks) {
currentIs.close();
currentIs = am.open(baseName + ++currentChunk + ext, AssetManager.ACCESS_STREAMING);
skipped += skip(n - skipped);
}
return skipped;
}
}
Usage:
ObjectInputStream ois = new ObjectInputStream(new SplitFileInputStream("mytempfile", ".dat", 4, getAssets()));

Change the file extension to .mp3

I know this is an old question but I thought of a good solution.
Why not store the file already pre-zipped in the asset folder.
Then since it is already a zip file and therefore compressed it won't need to be compressed again. So if you wanted the file to be compressed to decrease the size of your apk but you don't want to deal with splitting up files I think this is easier.
When you need to read that file off the device just wrap the inputstream in a zipinputstream
http://developer.android.com/reference/java/util/zip/ZipInputStream.html

I found another solution, maybe you're interested in it.
In the root of your sources, where you have the build.xml file, you can overwrite the -package-resources target in the custom_rules.xml file, which is used for adding/modifying targets in ant without breaking anything in the standard android app build system.
Just create a file with this content:
<?xml version="1.0" encoding="UTF-8"?>
<project name="yourAppHere" default="help">
<target name="-package-resources" depends="-crunch">
<!-- only package resources if *not* a library project -->
<do-only-if-not-library elseText="Library project: do not package resources..." >
<aapt executable="${aapt}"
command="package"
versioncode="${version.code}"
versionname="${version.name}"
debug="${build.is.packaging.debug}"
manifest="${out.manifest.abs.file}"
assets="${asset.absolute.dir}"
androidjar="${project.target.android.jar}"
apkfolder="${out.absolute.dir}"
nocrunch="${build.packaging.nocrunch}"
resourcefilename="${resource.package.file.name}"
resourcefilter="${aapt.resource.filter}"
libraryResFolderPathRefid="project.library.res.folder.path"
libraryPackagesRefid="project.library.packages"
libraryRFileRefid="project.library.bin.r.file.path"
previousBuildType="${build.last.target}"
buildType="${build.target}"
ignoreAssets="${aapt.ignore.assets}">
<res path="${out.res.absolute.dir}" />
<res path="${resource.absolute.dir}" />
<nocompress /> <!-- forces no compression on any files in assets or res/raw -->
<!-- <nocompress extension="xml" /> forces no compression on specific file extensions in assets and res/raw -->
</aapt>
</do-only-if-not-library>
</target>
</project>

add file extension is mp3.I use mydb.mp3in assets folder and copy .this run without error.show check it.

Using GZIP would be another method. you only need to wrap InputStream inside GZIPInputStream. I used this for a database which size about 3.0 MB and output compress file was about 600KB.
For copying DB in firs run, I gzipped my source .db file using GZIP
tool.
Then renamed it to .jpg in order to avoid more compression
(these processes are done before compile APK FILE).
Then for reading compressed GZIP file from assetss
and copying it:
private void copydatabase() throws IOException {
// Open your local db as the input stream
InputStream myinput = mContext.getAssets().open(DB_NAME_ASSET);
BufferedInputStream buffStream = new BufferedInputStream(myinput);
GZIPInputStream zis = new GZIPInputStream(buffStream);
// Path to the just created empty db
String outfilename = DB_PATH + DB_NAME;
// Open the empty db as the output stream
OutputStream myoutput = new FileOutputStream(outfilename);
// transfer byte to inputfile to outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = zis.read(buffer)) > 0) {
myoutput.write(buffer, 0, length);
}
// Close the streams
myoutput.flush();
myoutput.close();
zis.close();
buffStream.close();
myinput.close();
}

set database to multiple part with a program e.g "Win Hex", you can download from Link
and continue Load files bigger than 1M from assets folder

Instead of assets folder, I have put my large files in the raw folder. It works for me.

I use NetBeans to build the package and I not found how to change the settings of AAPT.
I have not tried the png, but the mp3 are compressed.
I can compile the package and then enter the assets folder with the parameter -0?
what would be the correct command to use?