Develop Reference

MP3 JID3 Library amendments

Help needed
I use the JID3 library to edit mp3 tags. This works fine as long as the music is on an internal sdcard. However, for api 19+ this no longer works for the external sdcard.
I understand I need to implement the Storage Access Framework but have no idea how to go about this.
The way JID3 works is it reads the mp3 file, extracts the tag(s) under consideration, say artist, updates the tag(s) with the new value.
the following steps need amendment:
create a .tmp file in the actual folder where the track resides, which ends up as the actual track with amended tag(s)
delete original track
rename the tmp file with the original track name.
I posted the relevant pieces of code
public class MP3File extends MediaFile
// create temporary file to work with
try
{
oTmpFileSource = m_oFileSource.createTempFile("id3.", ".tmp");
}
catch (Exception e)
{
throw new ID3Exception("Unable to create temporary file.", e);
}
m_oFileSource.delete();
oTmpFileSource.renameTo(m_oFileSource);
public class FileSource implements IFileSource
public IFileSource createTempFile(String sPrefix, String sSuffix)
throws IOException
{
File oTmpFile = File.createTempFile("id3.", ".tmp", m_oFile.getAbsoluteFile().getParentFile());
return new FileSource(oTmpFile);
}
public boolean delete()
{
return m_oFile.delete();
}
public boolean renameTo(IFileSource oFileSource)
throws IOException
{
if ( ! (oFileSource instanceof FileSource))
{
throw new IOException("Cannot rename between different file source types.");
}
return m_oFile.renameTo(((FileSource)oFileSource).m_oFile);
}

Android: Tesseract couldn't load any languages

Hi guys I am trying to run Tesseract and get the text from an image but I encounter the following error:
Exception in thread "main" java.lang.Error: Invalid memory access
at com.sun.jna.Native.invokePointer(Native Method)
at com.sun.jna.Function.invokePointer(Function.java:477)
at com.sun.jna.Function.invoke(Function.java:411)
at com.sun.jna.Function.invoke(Function.java:323)
at com.sun.jna.Library$Handler.invoke(Library.java:236)
at com.sun.proxy.$Proxy0.TessBaseAPIGetUTF8Text(Unknown Source)
at net.sourceforge.tess4j.Tesseract.getOCRText(Tesseract.java:436)
at net.sourceforge.tess4j.Tesseract.doOCR(Tesseract.java:291)
at net.sourceforge.tess4j.Tesseract.doOCR(Tesseract.java:212)
at net.sourceforge.tess4j.Tesseract.doOCR(Tesseract.java:196)
at Crop_Image.main(Crop_Image.java:98)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:144)
Error opening data file ./tessdata/eng.traineddata
Please make sure the TESSDATA_PREFIX environment variable is set to the parent directory of your "tessdata" directory.
Failed loading language 'eng'
Tesseract couldn't load any languages!
I am loading an image file jpg containing english text. This is how I try to load the file and then try to get the text from it:
public static void main(String[] args){
String result = "";
File imageFile = new File("C:\\Users\\user\\Desktop\\Untitled.jpg");
Tesseract instance = new Tesseract();
try {
result = instance.doOCR(imageFile);
result.toString();
} catch (Exception e) {
e.printStackTrace();
System.err.println(e.getMessage());
}
}
Also I am also inside my project using Maven and here is my pom file:
<dependencies>
<dependency>
<groupId>nu.pattern</groupId>
<artifactId>opencv</artifactId>
<version>2.4.9-4</version>
</dependency>
<dependency>
<groupId>net.sourceforge.tess4j</groupId>
<artifactId>tess4j</artifactId>
<version>3.1.0</version>
</dependency>
</dependencies>
What could be the cause of this error?

I saw your code and there might be an issue in the way you initialize Tesseract. Now since you are using maven as nguyenq suggested you need to point exactly to the location of the library - tessdata so here is what you should do:
public static String Image_To_Text(String image_path){
String result = "";
File imageFile = new File("your path to your image");
Tesseract instance = Tesseract.getInstance();
//In case you don't have your own tessdata, let it also be extracted for you
File tessDataFolder = LoadLibs.extractTessResources("tessdata");
//Set the tessdata path
instance.setDatapath(tessDataFolder.getAbsolutePath());
try {
result = instance.doOCR(imageFile);
} catch (Exception e) {
e.printStackTrace();
}
return result;
}

You need to set instance.setDatapath to the parent directory of tessdata folder.
File tessDataFolder = LoadLibs.extractTessResources("tessdata"); // Maven build bundles English data
instance.setDatapath(tessDataFolder.getParent());
See http://tess4j.sourceforge.net/tutorial.

Android Resource not found in ProviderTestCase2

I'm currently writing a csv-file-importer for my app, but I have difficulties writing tests for it. What I'm trying to do is import a sample csv file and compare the results to the database.
public class CSVImportTest extends ProviderTestCase2<MyProvider> {
#Override
protected void setUp() throws Exception {
super.setUp();
mContentResolver = getMockContentResolver();
setContext(new IsolatedContext(mContentResolver, getContext()));
mContext = getContext();
mCSVImport = new CSVImportParker(mContext);
}
public void read() {
try {
// Fails here with "File not found."
InputStream input = mContext.getResources()
.openRawResource(my.package.R.raw.file);
...
} catch (Exception e) {
e.printStackTrace();
fail();
}
...
}
}
The test file is never found, although it is available at the correct location.

The issue is that resources in the raw directory are compressed unless they have an ogg or mp3 file extension. See this description:
Proguard breaking audio file in assets or raw
and from the docs
This function only works for resources that are stored in the package as uncompressed data, which typically includes things like mp3 files and png images.
So, the easiest way to solve the issue is by adding the mp3 or ogg file extension to your raw assets. It's not clean or pretty but it works.

Access WordNet dict files in Android app

I'm writing a word game in Android. It's my first app so my knowledge is almost non-existent.
What I would like to do is use JWI to access the WordNet dictionary. This requires specifying the WordNet dictionary's file path.
From what I've read, Android "assets" are not available via a simple file path, but what JWI requires to initialize the WordNet dictionary API is a URL to the disk location of the dictionary files.
So, what is the best course of action? Should I copy the assets at startup-time into a known folder on the android device? I can't think of a better way but that seems entirely stupid to me.
Any help gratefully received.

I have the same problem (for a jetty webapp however and not android) and tried those two approaches, however unsuccessfully:
JWNL.initialize(this.getClass().getClassLoader().getResourceAsStream("wordnet_properties.xml");
dict = Dictionary.getInstance();
Here it successfully loads wordnet_properties.xml but it cannot access the dictionary which is pointed to by the properties file.
Using the dictionary folder directly:
String dictPath = "models/en/wordnet/dict/";
URL url = this.getClass().getClassLoader().getResource(dictPath);
System.out.println("loading wordnet from "+url);
dict = new RAMDictionary(url, ILoadPolicy.NO_LOAD);
Here I get the dictionary URL to be jar:file:/home/myusername/.m2/repository/package/1.0-SNAPSHOT/commons-1.0-SNAPSHOT.jar!/models/en/wordnet/dict/. WordNet however doesn't accept the jar protocol and gives me the error:
java.lang.IllegalArgumentException: URL source must use 'file' protocol
at edu.mit.jwi.data.FileProvider.toFile(FileProvider.java:693)
at edu.mit.jwi.data.FileProvider.open(FileProvider.java:304)
at edu.mit.jwi.DataSourceDictionary.open(DataSourceDictionary.java:92)
at edu.mit.jwi.RAMDictionary.open(RAMDictionary.java:216)
My next investigation will be to create a subclass to RAMDictionary or something similar, please tell me if you have found a solution in the meantime.
P.S.: I just wrote the developer a mail asking for help after I tried to rewrite the FileProvider to use resources instead but after one or two hours I gave up because the code calls so much other code that also only works with files. I will keep you up to date!
P.P.S.: I received an answer from the developer saying that it is principially not possible with streams because they don't offer random access which is necessary. However, he offered to implement a solution to load it all in RAM, if really necessary, but that would use up about 500 MB and I guess that is too much for android apps so I guess it is still best to unpack it somewhere.
P.S.: Here is my unpacking solution (you can replace the System.out.println statements with logger statements if you use logging or remove them if you don't like them):
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URISyntaxException;
import java.util.Enumeration;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
/** Allows WordNet to be run from within a jar file by unpacking it to a temporary directory.**/
public class WordNetUnpacker
{
static final String ID = "178558556719"; // minimize the chance of interfering with an existing directory
static final String jarDir = "models/en/wordnet/dict";
/**If running from within a jar, unpack wordnet from the jar to a temp directory (if not already done) and return that.
* If not running from a jar, just return the existing wordnet directory.
* #see getUnpackedWordNetDir(Class)*/
static File getUnpackedWordNetDir() throws IOException
{return getUnpackedWordNetDir(WordNetUnpacker.class);}
/**If running from within a jar, unpack wordnet from the jar to a temp directory (if not already done) and return that.
* If not running from a jar, just return the existing wordnet directory.
* #param clazz the class in whose classloader the wordnet resources are found.
* #see getUnpackedWordNetDir()**/
static File getUnpackedWordNetDir(Class clazz) throws IOException
{
String codeSource = clazz.getProtectionDomain().getCodeSource().getLocation().getPath();
System.out.println("getUnpackedWordNetDir: using code source "+codeSource);
if(!codeSource.endsWith(".jar"))
{
System.out.println("not running from jar, no unpacking necessary");
try{return new File(WordNetUnpacker.class.getClassLoader().getResource(jarDir).toURI());}
catch (URISyntaxException e) {throw new IOException(e);}
}
try(JarFile jarFile = new JarFile(codeSource))
{
String tempDirString = System.getProperty("java.io.tmpdir");
if(tempDirString==null) {throw new IOException("java.io.tmpdir not set");}
File tempDir = new File(tempDirString);
if(!tempDir.exists()) {throw new IOException("temporary directory does not exist");}
if(!tempDir.isDirectory()) {throw new IOException("temporary directory is a file, not a directory ");}
File wordNetDir = new File(tempDirString+'/'+"wordnet"+ID);
wordNetDir.mkdir();
System.out.println("unpacking jarfile "+jarFile.getName());
copyResourcesToDirectory(jarFile, jarDir, wordNetDir.getAbsolutePath());
return wordNetDir;
}
}
/** Copies a directory from a jar file to an external directory. Copied from Stack Overflow. */
public static void copyResourcesToDirectory(JarFile fromJar, String jarDir, String destDir) throws IOException
{
int copyCount = 0;
for (Enumeration<JarEntry> entries = fromJar.entries(); entries.hasMoreElements();)
{
JarEntry entry = entries.nextElement();
if(!entry.getName().contains("models")) continue;
if (entry.getName().startsWith(jarDir) && !entry.isDirectory()) {
copyCount++;
File dest = new File(destDir + "/" + entry.getName().substring(jarDir.length() + 1));
File parent = dest.getParentFile();
if (parent != null) {
parent.mkdirs();
}
FileOutputStream out = new FileOutputStream(dest);
InputStream in = fromJar.getInputStream(entry);
try {
byte[] buffer = new byte[8 * 1024];
int s = 0;
while ((s = in.read(buffer)) > 0) {
out.write(buffer, 0, s);
}
} catch (IOException e) {
throw new IOException("Could not copy asset from jar file", e);
} finally {
try {
in.close();
} catch (IOException ignored) {}
try {
out.close();
} catch (IOException ignored) {}
}
}
}
if(copyCount==0) System.out.println("Warning: No files copied!");
}
}

You can just copy all dict files from "assets" to the internal directory of your app. Just do it once, on the first app launch.
Since then you can use JWI in a causual way like this:
String path = getFilesDir() + "/dict";
URL url = new URL("file", null, path);
IDictionary dict = new Dictionary(url);

How to provide data files for android unit tests

I am developing software that loads information from XML files using Android's implementation of java.xml.parsers.DocumentBuilder and DocumentBuilderFactory. I am writing unit tests of my objects and I need to be able to provide a variety of xml files that will exercise the code under test. I am using Eclipse and have a separate Android Test Project. I cannot find a way to put the test xml into the test project such that the code under test can open the files.
If I put the files in /assets of the test project, the code under test cannot see it.
If I put the files in the /assets of the code under test, it can of course see the files, but now I'm cluttering up my actual system with test only data files.
If I hand copy the files to the /sdcard/data directory, I can open them from the code under test, but that interferes with automating my tests.
Any suggestions of how to have different xml test files reside in the test package but be visible to the code under test would be greatly appreciated.
Here is how I tried to structure the unit test:
public class AppDescLoaderTest extends AndroidTestCase
{
private static final String SAMPLE_XML = "sample.xml";
private AppDescLoader m_appDescLoader;
private Application m_app;
protected void setUp() throws Exception
{
super.setUp();
m_app = new Application();
//call to system under test to load m_app using
//a sample xml file
m_appDescLoader = new AppDescLoader(m_app, SAMPLE_XML, getContext());
}
public void testLoad_ShouldPopulateDocument() throws Exception
{
m_appDescLoader.load();
}
}
This did not work as the SAMPLE_XML file is in the context of the test, but AndroidTestCase is providing a context for the system under test, which cannot see an asset from the test package.
This is the modified code that worked per answer given:
public class AppDescLoaderTest extends InstrumentationTestCase
{
...
protected void setUp() throws Exception
{
super.setUp();
m_app = new Application();
//call to system under test to load m_app using
//a sample xml file
m_appDescLoader = new AppDescLoader(m_app, SAMPLE_XML, getInstrumentation().getContext());
}

Option 1: Use InstrumentationTestCase
Suppose you got assets folder in both android project and test project, and you put the XML file in the assets folder. in your test code under test project, this will load xml from the android project assets folder:
getInstrumentation().getTargetContext().getResources().getAssets().open(testFile);
This will load xml from the test project assets folder:
getInstrumentation().getContext().getResources().getAssets().open(testFile);
Option 2: Use ClassLoader
In your test project, if the assets folder is added to project build path (which was automatically done by ADT plugin before version r14), you can load file from res or assets directory (i.e. directories under project build path) without Context:
String file = "assets/sample.xml";
InputStream in = this.getClass().getClassLoader().getResourceAsStream(file);

For Android and JVM unit tests I use following:
public final class DataStub {
private static final String BASE_PATH = resolveBasePath(); // e.g. "./mymodule/src/test/resources/";
private static String resolveBasePath() {
final String path = "./mymodule/src/test/resources/";
if (Arrays.asList(new File("./").list()).contains("mymodule")) {
return path; // version for call unit tests from Android Studio
}
return "../" + path; // version for call unit tests from terminal './gradlew test'
}
private DataStub() {
//no instances
}
/**
* Reads file content and returns string.
* #throws IOException
*/
public static String readFile(#Nonnull final String path) throws IOException {
final StringBuilder sb = new StringBuilder();
String strLine;
try (final BufferedReader reader = new BufferedReader(new InputStreamReader(new FileInputStream(path), "UTF-8"))) {
while ((strLine = reader.readLine()) != null) {
sb.append(strLine);
}
} catch (final IOException ignore) {
//ignore
}
return sb.toString();
}
}
All raw files I put into next path: ".../project_root/mymodule/src/test/resources/"

Try this for Kotlin:
val json = File("src\\main\\assets\\alphabets\\alphabets.json").bufferedReader().use { it.readText() }