I want to read in the data from a csv-file and store it into a database. This is how I saved the csv-file (this works without errors - just to show where and how the file is stored which I plan to read with CSVreader):
synchronized public void readFromUrl(String url, String outputFile, Context context) throws FileNotFoundException {
URL downloadLink = null;
try {
downloadLink = new URL(url);
} catch (MalformedURLException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}
BufferedReader in = null;
try {
in = new BufferedReader(
new InputStreamReader(downloadLink.openStream(), "UTF8"));
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
FileOutputStream fstream = context.openFileOutput(outputFile,Context.MODE_PRIVATE);
Writer out = new OutputStreamWriter(fstream);
Log.d(TAG, "BufferedReader "+in);
String inputLine = null;
try {
while ((inputLine = in.readLine()) != null){
out.write(inputLine+"\n");
//logger.debug("DOWNLOADED: "+inputLine);
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
fstream.close();
out.close();
in.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
My code so far for reading the csv file:
public void readInCSVFile(String filename, Context context) throws IOException {
IDbHelper dbHelper = new DbHelper(); ;
CSVReader products = null;
products = new CSVReader(new InputStreamReader(context.getAssets().open(filename)));
I get a NoClassDefFoundError exception.
I have the opencsv.jar in the Referenced libraries of my android project.
Thanks in advance for your help.
Is your project in the Eclipse IDE? If yes, then have a look whether the lib (opencsv.jar) is set in the "project properties->Java Build Path->Libraries" and that it is checked in the tab: "Order and Export" too. Under "Order and Export" move the lib to the top of the list.
Then clean and rebuild.
PS: If this does not help, then please provide the complete stacktrace of the error.
Related
I need when app starts, to check if file exists, if not to be created..
I need a block of code to append files into it
than I need a block of code that read that text line by line
than to remove a line ....
I found this code at stackoverflow, and they said that the file will be created in that location...
//Here I have this :
//Do not hardcode "/data/"; use Context.getFilesDir().getPath() instead
//
String filePath = "/data/data/com.example.myapp/files/text.txt";
File file = new File(filePath);
if(file.exists()){
//Do nothing
}
else{
try {
final String TESTSTRING = new String("");
FileOutputStream fOut = openFileOutput("text.txt", MODE_WORLD_READABLE);
OutputStreamWriter osw = new OutputStreamWriter(fOut);
osw.write(TESTSTRING);
osw.flush();
osw.close();
} catch (IOException ioe)
{ioe.printStackTrace();}
}
}
To add Lines in text I made this :
private void write(){
S ="/data/data/com.example.myapp/files/text.txt";
try {
writer = new FileWriter(S, true);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
writer.write(emri.getText().toString() + "\n" + link.getText().toString());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}finally {
try {
writer.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
And when I have to read them :
public class PlayList extends ListActivity {
ArrayList<String> listaE = new ArrayList<String>();
ArrayList<String> listaL = new ArrayList<String>();
InputStream instream;
int resh=0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
lexo();
String[] mStringArray = new String[listaE.size()];
mStringArray = listaE.toArray(mStringArray);
setListAdapter(new ArrayAdapter<String>(PlayList.this,android.R.layout.simple_list_item_1,mStringArray));
}
private void lexo(){
String S ="/data/data/com.example.myapp/files/text.txt";
try {
// open the file for reading
instream = new FileInputStream(S);
// if file the available for reading
if (instream != null) {
// prepare the file for reading
InputStreamReader inputreader = new InputStreamReader(instream);
BufferedReader buffreader = new BufferedReader(inputreader);
String line;
// read every line of the file into the line-variable, on line at the time
do {
line = buffreader.readLine();
if ((resh % 2) == 0) {
listaL.add(line);
}
else {
listaE.add(line);
}
// do something with the line
} while (line != null);
}
} catch (Exception ex) {
// print stack trace.
} finally {
// close the file.
try {
instream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
My code does not work at all, and is missing the code to remove a line..
So everything I need is :
Code to write into file ( file to be saved because will be used until the app will be installed )
Code to read that file line by line ( so to be added in array, odd lines in one array, other lines in another array )
Code to remove a line from that file ( array to be added in listview and when user touches the line, touched line to be removed )
To add lines on list-activity
Any help will be very very appreciated,
Thanks...
First of all, you should use .getFilesDir().getPath() on your app's context, instead of hardcoding the path. That's commented in your first block. Second, create an OutputStream like this:
OutputStream out = new FileOutputStream(filePath);
If you have an InputStream called in, you'll be able to write it to a file using this code:
byte[] buf = new byte[1024];
int len;
while ((len = in.read(buf)) > 0) out.write(buf, 0, len);
in.close();
out.close();
When you do create a file, check the rest (I didn't look) and get back to StackOverlow, if it fails. Don't make any of us do all the work, okay? Rip it to small part and make an effort.
Good luck with your work.
I'm so confused. After reading this thread, I'm trying to write a List to internal storage onPause(), then read the List onResume(). Just for testing purposes, I'm trying to write a simple string as the example showed. I've got this to write with:
String FILENAME = "hello_file";
String string = "hello world!";
FileOutputStream fos = null;
try {
fos = openFileOutput(FILENAME, Context. MODE_WORLD_READABLE);
} catch (FileNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
fos.write(string.getBytes());
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
fos.close();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
And I'm trying to read it in onResume() by calling:
try {
resultText01.setText(readFile("hello_file"));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
resultText01.setText("exception, what went wrong? why doesn't this text say hello world!?");
}
Which of course uses this:
private static String readFile(String path) throws IOException {
FileInputStream stream = new FileInputStream(new File(path));
try {
FileChannel fc = stream.getChannel();
MappedByteBuffer bb = fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size());
/* Instead of using default, pass in a decoder. */
return Charset.defaultCharset().decode(bb).toString();
}
finally {
stream.close();
}
}
For some reason, resultText01.setText(...) isn't being set to "hello world!", and is instead calling the catch exception. I'm sorry if my lingo isn't correct, I'm new to this. Thanks for any pointers.
Instead of the following in your readFile(...) method...
FileInputStream stream = new FileInputStream(new File(path));
Try...
FileInputStream stream = openFileInput(path);
This is my first attempt at serializing/deserializing objects on any platform and, to put it mildly, I'm confused.
After implementing Serializable to my game object I output it to a file thus:
public void saveGameState(){
ByteArrayOutputStream bos = new ByteArrayOutputStream();
try {
ObjectOutput out = new ObjectOutputStream(bos);
out.writeObject(theGame);//theGame is an instance of the custom class
//TGame which stores game info.
byte[] buf = bos.toByteArray();
FileOutputStream fos = this.openFileOutput(filename,
Context.MODE_PRIVATE);
fos.write(buf);
fos.close();
} catch(IOException ioe) {
Log.e("serializeObject", "error", ioe);
}
File f =this.getDir(filename, 0);
Log.v("FILE",f.getName());
}
This seems to work, in that I get no exceptions raised. I can only know for sure when I deserialize it. Which is where things go pear shaped.
public God loadSavedGame(){
TGame g=null;
InputStream instream = null;
try {
instream = openFileInput(filename);
} catch (FileNotFoundException e) {
e.printStackTrace();
return null;
}
try {
ObjectInputStream ois = new ObjectInputStream(instream);
try {
g= (TGame) ois.readObject();
return g;
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
}
} catch (StreamCorruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
}
}
I got the basis of this code from here Android Java -- Deserializing a file on the Android platform and tried to modify it for my app. When running I get
05-31 23:30:45.493: ERROR/copybit(1279): copyBits failed (Invalid argument)
When the output should be loaded and the saved game start up from when it was saved.
Any help would be appreciated.
The error you've shown is not at all related to serialization: its actually a video display error. I'd suggest looking at the object BEFORE you serialize to make sure its not null, and I'd also suggest serializing to a file on the SD card to make sure you actually had data output (so use new FileOutputStream("/mnt/sdcard/serializationtest") as the output stream and new FileInputStream("/mnt/sdcard/serializationtest") as the input stream) while you are debugging; you can switch back to the context methods after it works, but make sure your sdcard is plugged in while you are doing this.
Finally, modify your logging to look like this:
try {
ObjectInputStream ois = new ObjectInputStream(instream);
try {
g= (TGame) ois.readObject();
return g;
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
android.util.Log.e("DESERIALIZATION FAILED (CLASS NOT FOUND):"+e.getMessage(), e);
e.printStackTrace();
return null;
}
} catch (StreamCorruptedException e) {
android.util.Log.e("DESERIALIZATION FAILED (CORRUPT):"+e.getMessage(), e);
// TODO Auto-generated catch block
e.printStackTrace();
return null;
} catch (IOException e) {
android.util.Log.e("DESERIALIZATION FAILED (IO EXCEPTION):"+e.getMessage(), e);
// TODO Auto-generated catch block
e.printStackTrace();
return null;
}
and see what error gets returned. I expect the serialization is failing somehow.
To seralize or deserialize anything you can use SIMPLE api. It is very easy to use. Download the file and use it in your program
Have a look here
http://simple.sourceforge.net/download/stream/doc/tutorial/tutorial.php#deserialize
Thanks Deepak
I have created below class to do the save and retrieve object.
public class SerializeUtil {
public static <T extends Serializable> void saveObjectToFile(Context context, T object, String fileName){
try {
FileOutputStream fos = context.openFileOutput(fileName, Context.MODE_PRIVATE);
ObjectOutputStream os = new ObjectOutputStream(fos);
os.writeObject(object);
os.close();
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
public static<T extends Serializable> T getObjectFromFile(Context context, String fileName){
T object = null;
try {
FileInputStream fis = context.openFileInput(fileName);
ObjectInputStream is = new ObjectInputStream(fis);
object = (T) is.readObject();
is.close();
fis.close();
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
return object;
}
public static void removeSerializable(Context context, String filename) {
context.deleteFile(filename);
}
}
I'm having a software who is doing a http GET request and then I am receiving an HttpEntity response.
This is fine to me. The problem is that I want to use read this response 2 times and I dont know which way is the best.
If I convert the entity to a string, then when I try to access again the entity, Im getting an exception that the entity has been consumed.
If I try to use the getContent method to use the InputStream I dont find a way to reread the inputStream 2 times as i need.
Can someone tell me how I can save the httpEntity result as a way I can reuse it twice ?? Shoud I create a file ? How I do that ? What about performance to write a file each time I do a GET ? How to delete that file on each call ? Where to save the file ?
If you have any other ideas, thanks for the help.
I will appreciate code examples.
I finally found how to convert a stream to a string so I did the following thing :
//Get the answer from http request
if(httpResponse!=null)
entity = httpResponse.getEntity();
else
entity = null;
//Display the answer in the UI
String result;
if (entity != null) {
//First, Open a file for writing
FileOutputStream theXMLFile=null;
try{
theXMLFile=openFileOutput("HttpResponse.dat", MODE_PRIVATE);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.e("ResultService Exception :", e.getMessage());
}
try {
if(theXMLFile!=null) {
//Save the stream to a file to be able to re read it later.
entity.writeTo(theXMLFile);
//Entity is consumed now and cannot be reuse ! Lets free it.
entity=null;
//Now, lets read this file !
FileInputStream theXMLStream=null;
try {
//Open the file for reading and convert to a string
theXMLStream = openFileInput("HttpResponse.dat");
result=com.yourutilsfunctionspackage.ServiceHelper.convertStreamToString(theXMLStream);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.e("ResultService Exception :", e.getMessage());
result=null;
}
theXMLStream.close();
theXMLStream=null;
//Use the string for display
if(result!=null)
infoTxt.setText(getText(R.string.AnswerTitle) + " = " +result);
try {
//Reopen the file because you cannot use a FileInputStream twice.
theXMLStream = openFileInput("HttpResponse.dat");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
Log.e("ResultService Exception :", e.getMessage());
}
//Re use the stream as you want for decoding xml
if(theXMLStream!=null){
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder=null;
try {
builder = factory.newDocumentBuilder();
} catch (ParserConfigurationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if(builder!=null)
{
Document dom=null;
try {
dom = builder.parse(theXMLStream);
} catch (SAXException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if(dom!=null){
Element racine = dom.getDocumentElement();
NodeList nodeLst=racine.getElementsByTagName("response");
Node fstNode = nodeLst.item(0);
if(fstNode!=null){
Element fstElmnt = (Element) fstNode;
String CallingService=fstElmnt.getAttribute("service");
etc....
//Function taken from internet http://www.kodejava.org/examples/266.html
public static String convertStreamToString(InputStream is) throws IOException {
/*
* To convert the InputStream to String we use the
* Reader.read(char[] buffer) method. We iterate until the
* Reader return -1 which means there's no more data to
* read. We use the StringWriter class to produce the string.
*/
if (is != null) {
Writer writer = new StringWriter();
char[] buffer = new char[1024];
try {
Reader reader = new BufferedReader(
new InputStreamReader(is, "UTF-8"));
int n;
while ((n = reader.read(buffer)) != -1) {
writer.write(buffer, 0, n);
}
} finally {
is.close();
}
return writer.toString();
} else {
return null;
}
}
I just wanna create a text file into phone memory and have to read its content to display.Now i created a text file.But its not present in the path data/data/package-name/file name.txt & it didn't display the content on emulator.
My code is..
public class PhonememAct extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
TextView tv=(TextView)findViewById(R.id.tv);
FileOutputStream fos = null;
try {
fos = openFileOutput("Test.txt", Context.MODE_PRIVATE);
} catch (FileNotFoundException e2) {
// TODO Auto-generated catch block
e2.printStackTrace();
}
try {
fos.write("Hai..".getBytes());
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
fos.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
FileInputStream fis = null;
try {
fis = openFileInput("Test.txt");
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
int c;
try {
while((c=fis.read())!=-1)
{
tv.setText(c);
setContentView(tv);
//k += (char)c;
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
fis.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
Thanks in adv.
You don't need to use input/output streams if you are simply trying to write/read text.
Use FileWriter to write text to a file and BufferedReader to read text from a file - it's much simpler. This works perfectly...
try {
File myDir = new File(getFilesDir().getAbsolutePath());
String s = "";
FileWriter fw = new FileWriter(myDir + "/Test.txt");
fw.write("Hello World");
fw.close();
BufferedReader br = new BufferedReader(new FileReader(myDir + "/Test.txt"));
s = br.readLine();
// Set TextView text here using tv.setText(s);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
//Find the directory for the SD Card using the API
//*Don't* hardcode "/sdcard"
File sdcard = Environment.getExternalStorageDirectory();
//Get the text file
File file = new File(sdcard,"file.txt");
//Read text from file
StringBuilder text = new StringBuilder();
try {
BufferedReader br = new BufferedReader(new FileReader(file));
String line;
while ((line = br.readLine()) != null) {
text.append(line);
text.append('\n');
}
}
catch (IOException e) {
//You'll need to add proper error handling here
}
//Find the view by its id
TextView tv = (TextView)findViewById(R.id.text_view);
//Set the text
tv.setText(text);
//To read file from internal phone memory
//get your application context:
Context context = getApplicationContext();
filePath = context.getFilesDir().getAbsolutePath();
File file = new File(filePath, fileName);
StringBuilder text = new StringBuilder();
try {
BufferedReader br = new BufferedReader(new FileReader(file));
while ((line = br.readLine()) != null) {
text.append(line);
text.append('\n');
}
}
catch (IOException e) {
}
return text.toString(); //the output text from file.
This may not be an answer to your question.
I think, you need to use the try-catch correctly.
Imagine openFileInput() call fails, and next you are calling fos.write() and fos.close() on a null object.
Same thing is seen later in fis.read() and fis.close().
You need to include openFileInput(), fos.write() and fos.close() in one single try-catch block. Similar change is required for 'fis' as well.
Try this first!
You could try it with a stream.
public static void persistAll(Context ctx, List<myObject> myObjects) {
// save data to file
FileOutputStream out = null;
try {
out = ctx.openFileOutput("file.obj",
Context.MODE_PRIVATE);
ObjectOutputStream objOut = new ObjectOutputStream(out);
objOut.writeObject(myObjects);
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
It is working fine for me like this. Saving as text shouldn't be that different, but I don't have a Java IDE to test here at work.
Hope this helps!