Develop Reference

Android Studio, FileWriter not creating

I am trying to use FileWrite to write sensor data of the phone. But I could the get the basic generating new FileWriter working. It seems to return null. Here is the code, basically it tries to create a writer when a button is clicked then just write a few lines of 'hi'. But the program catches the exception at writer = new FileWriter(destPath, true); and Writer unsuccess. is toasted. Any idea why this error happens?
package com.example.jiajunyang.bowdetection;
import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
import java.io.File;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.IOException;
public class MainActivity extends AppCompatActivity implements SensorEventListener
{
private static final String destPath = "mySensorData.txt";
FileWriter writer;
// Used to load the 'native-lib' library on application startup.
static {
System.loadLibrary("native-lib");
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
File sdCardFile = new File(Environment.getExternalStorageDirectory() + " \filename.txt");
Log.d("TAG", sdCardFile.getPath());
}
public void onStartClick(View view) {
try {
writer = new FileWriter(destPath, true);
Toast.makeText(getApplicationContext(), "Start writer. ",
Toast.LENGTH_SHORT).show();
writer.write("hi \n");
writer.write("hi \n");
writer.write("hi \n");
writer.flush();
writer.close();
} catch (IOException e) {
Toast.makeText(getApplicationContext(), "Writer unsuccess. ",
Toast.LENGTH_SHORT).show();
e.printStackTrace();
}
}
}

I develop Mobile Applications with Java.
Some Java APIs just don't work with Android. Are you sure FileWriter does?
Also, the way you define your destination path seems a little bit odd to me.
Here is an Android code example:
String filename = "myfile";
String string = "Hello world!";
FileOutputStream outputStream;
try {
outputStream = openFileOutput(filename, Context.MODE_PRIVATE);
outputStream.write(string.getBytes());
outputStream.close();
} catch (Exception e) {
e.printStackTrace();
}
You can find more details here.

App will not connect to Firebase Storage- Will not open, No errors

I was going through a tutorial to create a voice recorder which will then upload the recording to Firebase. I watched the tutorial many times and made sure the app is connected to Firebase; however, the app will not open right now most likely due to this issue. I'm pretty new to Java programming. Can someone please provide me with some guidance? Thank you
package bfb.ess.myapplicationbfb;
import android.app.ProgressDialog;
import android.media.MediaRecorder;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.firebase.storage.FirebaseStorage;
import com.google.firebase.storage.StorageReference;
import com.google.firebase.storage.UploadTask;
import java.io.File;
import java.io.IOException;
public class speakp extends AppCompatActivity {
private Button mRecordBtn;
private TextView mRecordlabel;
private MediaRecorder mRecorder;
private String mFileName = null;
private static final String LOG_TAG = "Record_log";
private StorageReference mStorage;
private ProgressDialog mProgress;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.recordpage);
mStorage = FirebaseStorage.getInstance().getReference();
mRecordlabel = (TextView) findViewById(R.id.recordlabel);
mRecordBtn =(Button) findViewById(R.id.recordBtn);
mProgress = new ProgressDialog(this);
mFileName = Environment.getExternalStorageDirectory().getAbsolutePath();
mFileName +="/recorded_audio.3gp";
mRecordBtn.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View view, MotionEvent motionEvent) {
if(motionEvent.getAction() == MotionEvent.ACTION_DOWN) {
startRecording();
mRecordlabel.setText("Recording Started ...");
} else if (motionEvent.getAction() == MotionEvent.ACTION_UP) {
stopRecording();
mRecordlabel.setText("Recording Stopped ...");
}
return false;
}
});
}
private void startRecording() {
mRecorder = new MediaRecorder();
mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mRecorder.setOutputFile(mFileName);
mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
try {
mRecorder.prepare();
} catch (IOException e) {
Log.e(LOG_TAG, "prepare() failed");
}
mRecorder.start();
}
private void stopRecording() {
mRecorder.stop();
mRecorder.release();
mRecorder = null;
uploadAudio();
}
private void uploadAudio() {
mProgress.setMessage("Uploading Audio ...");
mProgress.show();
StorageReference filepath = mStorage.child("Audio").child("new_audio.3gp");
Uri uri = Uri.fromFile(new File(mFileName));
filepath.putFile(uri).addOnSuccessListener(new OnSuccessListener<UploadTask.TaskSnapshot>() {
#Override
public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
mProgress.dismiss();
mRecordlabel.setText("Uploading Finished");
}
});
}
}

Go to Firebase console and update read and write rules for storage
You can look into the Google Firebase Sample: Storage Sample
Please check the URI of audio file if its proper. Because I guess lastPathSegment of uri is getting faulty.
By Default:
service firebase.storage {
match /b/<name_of_app>/o {
match /{allPaths=**} {
allow read, write: if request.auth != null;
}
}
}
Update it to:
service firebase.storage {
match /b/<name_of_app>/o {
match /{allPaths=**} {
allow read;
allow write;
}
}
}
NOTE:
This update will allow you to store the data even if you are not authorised.
It is only for development purpose because it can cause security issue of accessing the data without getting authorised.
So take care when uploading the app to play store, update this parameter and change according to your requirement.

You need to update the read and write rules for storage in your firebase console,
Go to Firebase console, select storage
Click on the Rules tab
By Default:
service firebase.storage {
match /b/{bucket}/o {
match /{allPaths=**} {
allow read, write: if request.auth != null;
}
}
}
Change to:
service firebase.storage {
match /b/{bucket}/o {
match /{allPaths=**} {
allow read, write;
}
}
}
as Mohom.R said
NOTE: This update will allow you to store the data even if you are not authorised. It is only for development purpose because it can cause security issue of accessing the data without getting authorised. So take care when uploading the app to play store, update this parameter and change according to your requirement.

pdfbox manipulate pdf document - android

So I looked around a little bit to find a good PDF APIs for android and I've discovered PDFBox. I started to play with this library and mainly I'm looking for manipulating specific pdf form.
Now I am loading the file successfuly from my assets folder, but when I try to call
getAcroForm();
It turns me a null object, Thus I can't get into the fields and start to insert some data.
Here is the code where I load the pdf file, copy it to the sdcard and load it to an PDDocument object:
package com.silverfix.pdfpractice;
import android.content.res.AssetManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.Toast;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.PDDocumentCatalog;
import org.apache.pdfbox.pdmodel.interactive.form.PDAcroForm;
import org.apache.pdfbox.pdmodel.interactive.form.PDFieldTreeNode;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.List;
public class MainActivity extends AppCompatActivity{
private final String FORM_NAME = "dgc.pdf";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
try {
AssetManager assetManager = getAssets();
File file = createFileFromInputStream(assetManager.open(FORM_NAME));
PDDocument form = PDDocument.load(file);
PDDocumentCatalog catalog = form.getDocumentCatalog();
catalog.getPages().getCount();
Toast.makeText(this, "Loaded! " + catalog.getPages().getCount(), Toast.LENGTH_LONG).show();
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(this, "Loading has failed", Toast.LENGTH_LONG).show();
}
}
private File createFileFromInputStream(InputStream inputStream) {
try{
OutputStream outputStream = new FileOutputStream("/sdcard/PDFPractice/" + FORM_NAME);
byte buffer[] = new byte[1024];
int length = 0;
while((length=inputStream.read(buffer)) > 0) {
outputStream.write(buffer,0,length);
}
outputStream.close();
inputStream.close();
File result = new File("/sdcard/PDFPractice/" + FORM_NAME);
return result;
}catch (IOException e) {
e.printStackTrace();
}
return null;
}
}
How can I manipulate a pdf file without acroform? Or, can I add an somesort of acroform to this pdf file by myself?

Ok so I finally solved this problem. I downloaded Foxit PhantomPDF and it turns out you can define text fields and align them for your needs. I don't know if there is another software that does that but this one did the job for me

Transferring Multiple Files over Socket [duplicate]

This question already has answers here:
Java multiple file transfer over socket
(3 answers)
Closed 7 years ago.
I'm developing an application and I want to transfer files from a computer to a phone using sockets. I'm able to transfer one file but when I want to transfer multiple files, they pile up. Here's how the program works:
I get a screenshot from computer using Robot.
I save it as Send.jpg.
I send the image. Let's say for example its size is 1 MB.
I receive the image on phone.
I display it in an ImageView.
And loop through these steps again until the user closes the activity on phone.
But the result is this :
I get the first screenshot (Send.jpg: 1 MB) send it and receive it on phone. Get the second one (Send.jpg: 2 MB) send it and receive it on phone. and the third one and etc...
It never gets displayed on phone. And when I check the phone storage using explorer, I see one image - its size is the size of the first image + the second + the third ...
I guess my problem is i have to stop the InputStream, please help.
Code :
Server :
package application;
import java.awt.AWTException;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
import java.net.Socket;
import javax.imageio.ImageIO;
public class ScreenCapture {
Socket socket;
OutputStream os;
Robot robot;
PrintStream ps;
public ScreenCapture() throws IOException, AWTException {
// TODO Auto-generated constructor stub
socket = SocketWrapper.getSocket();
os = socket.getOutputStream();
robot = new Robot();
ps = new PrintStream(socket.getOutputStream());
new Record().start();
}
private class Record extends Thread{
#Override
public void run() {
while(true){
int count;
Rectangle rect = new Rectangle(Toolkit.getDefaultToolkit().getScreenSize());
BufferedImage img = robot.createScreenCapture(rect);
try {
ImageIO.write(img, "jpg", new File("/Users/Tomahawk/Documents/MovieMaker/send.jpg"));
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
FileInputStream fis;
try {
File f = new File("/Users/Tomahawk/Documents/MovieMaker/send.jpg");
fis = new FileInputStream(f);
BufferedInputStream bis = new BufferedInputStream(fis);
byte[] byteArray = new byte[(int) f.length()];
long filesize = f.length();
while((count = bis.read(byteArray)) > 0){
os.write(byteArray,0,count);
}
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
System.out.println("Sent File");
}
}
}
}
Client (Phone) :
package com.pcontrol.tomahawk.pcontrol;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ImageView;
import android.widget.Toast;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import java.util.Scanner;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
public class ScreenCapture extends Activity {
Socket socket;
InputStream is;
OutputStream os;
Scanner scanner;
ImageView screenCap;
long filesize = 0;
int i=0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_screen_capture);
socket = SocketWrapper.getSocket();
try {
is = socket.getInputStream();
scanner = new Scanner(is);
} catch (IOException e) {
e.printStackTrace();
}
screenCap = (ImageView) findViewById(R.id.screenCap);
new ReceiveFiles().execute();
}
private class ReceiveFiles extends AsyncTask<Void,Void,Void> {
#Override
protected Void doInBackground(Void... params) {
try {
os = new FileOutputStream("/sdcard/"+i+".jpg");
copy(is, os);
publishProgress();
} catch (IOException e) {
e.printStackTrace();
}
i++;
return null;
}
#Override
protected void onProgressUpdate(Void... values) {
Bitmap bmp = BitmapFactory.decodeFile("/sdcard/"+i+".jpg");
screenCap.setImageBitmap(bmp);
}
}
static void copy(InputStream in, OutputStream out) throws IOException {
byte[] buf = new byte[60000];
int len = 0;
while ((len = in.read(buf)) != -1) {
out.write(buf, 0, len);
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_screen_capture, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}

You're not telling the receiver where one file ends and the next one starts.
You could add a basic framing protocol, for example one where you first send the size of the file and then the data. That way the receiver can count the bytes it reads and knows when to close the current file and open another.
Alternatively you could use separate sockets to send each file, but it looks like that would require major changes to your architecture.

Android Java - How to download zip file from URL?

Hey Im making a new project which requires you to download some files from my Dropbox. I added a new class called DownloadFile which has the code to download a file. For some reason the app crashes when I click download. Thanks.
Heres the DownloadFile:
package com.Matt7262.download.app;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
//Chat bot library
import org.alicebot.ab.Chat;
import org.alicebot.ab.Bot;
import android.view.View;
import android.widget.Button;
import android.os.Environment;
import android.widget.TextView;
import android.widget.Toast;
import java.io.InputStream;
import java.net.URL;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import android.widget.ProgressBar;
import java.net.URL;
import java.net.URLConnection;
import android.app.Activity;
import android.app.ProgressDialog;
import android.os.Environment;
import android.view.View.OnClickListener;
public class DownloadFile extends ActionBarActivity{
public void updateProgress(int currentSize, int totalSize)
{
Toast.makeText(getApplicationContext(), "Loading Files...",
Toast.LENGTH_SHORT).show();
}
public void Download()
{
try {
//set the download URL, a url that points to a file on the internet
//this is the file to be downloaded
URL url = new URL("https://dl.dropboxusercontent.com/shz/9cyfz0b45mj6szr/7pBuupNz3N/xecta?token_hash=AAEs9cDFswt98D1IhLnab4dHwhwh5z2Lmhq_N6H-2M0LWg&top_level_offset=6");
//create the new connection
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
//set up some things on the connection
urlConnection.setRequestMethod("GET");
urlConnection.setDoOutput(true);
//and connect!
urlConnection.connect();
//set the path where we want to save the file
//in this case, going to save it on the root directory of the
//sd card.
File SDCardRoot = Environment.getExternalStorageDirectory();
//create a new file, specifying the path, and the filename
//which we want to save the file as.
File file = new File(SDCardRoot,"hello.zip");
//this will be used to write the downloaded data into the file we created
FileOutputStream fileOutput = new FileOutputStream(file);
//this will be used in reading the data from the internet
InputStream inputStream = urlConnection.getInputStream();
//this is the total size of the file
int totalSize = urlConnection.getContentLength();
//variable to store total downloaded bytes
int downloadedSize = 0;
//create a buffer...
byte[] buffer = new byte[1024];
int bufferLength = 0; //used to store a temporary size of the buffer
//now, read through the input buffer and write the contents to the file
while ( (bufferLength = inputStream.read(buffer)) > 0 ) {
//add the data in the buffer to the file in the file output stream (the file on the sd card
fileOutput.write(buffer, 0, bufferLength);
//add up the size so we know how much is downloaded
downloadedSize += bufferLength;
//this is where you would do something to report the prgress, like this maybe
updateProgress(downloadedSize, totalSize);
}
//close the output stream when done
fileOutput.close();
//catch some possible errors...
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
MainActivity:
package com.Matt7262.download.app;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
//Chat bot library
import org.alicebot.ab.Chat;
import org.alicebot.ab.Bot;
import android.view.View;
import android.widget.Button;
import android.os.Environment;
import android.widget.TextView;
import android.widget.Toast;
import android.os.AsyncTask;
public class MainActivity extends ActionBarActivity {
TextView input;
String dPath = Environment.getExternalStorageDirectory().getAbsolutePath() + "/Download";
private DownloadFile df;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
//EditText mEdit = (EditText)findViewById(R.id.editText1);
public void buttonOnClick(View v)
{
input = (TextView) findViewById(R.id.editText1);
String dbPath = Environment.getExternalStorageDirectory().getAbsolutePath() + "/Download/Ab";
Button button=(Button) v;
//Creating bot
String botname="xecta";
String path= dbPath;
Bot xecta = new Bot(botname, path);
Chat chatSession = new Chat(xecta);
String request = input.getText().toString();
String response = chatSession.multisentenceRespond(request);
((Button) v).setText(response);
}
public void onClickDownload(View view)
{
df.Download();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/*public void updateProgress(int currentSize, int totalSize)
{
Toast.makeText(getApplicationContext(), "Retrieving Files...",
Toast.LENGTH_SHORT).show();
}/*
/*public void Download()
{
try {
//set the download URL, a url that points to a file on the internet
//this is the file to be downloaded
URL url = new URL("https://dl.dropboxusercontent.com/shz/9cyfz0b45mj6szr/7pBuupNz3N/xecta?token_hash=AAEs9cDFswt98D1IhLnab4dHwhwh5z2Lmhq_N6H-2M0LWg&top_level_offset=6");
//create the new connection
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
//set up some things on the connection
urlConnection.setRequestMethod("GET");
urlConnection.setDoOutput(true);
//and connect!
urlConnection.connect();
//set the path where we want to save the file
//in this case, going to save it on the root directory of the
//sd card.
File SDCardRoot = Environment.getExternalStorageDirectory();
//create a new file, specifying the path, and the filename
//which we want to save the file as.
File file = new File(SDCardRoot,"hello.zip");
//this will be used to write the downloaded data into the file we created
FileOutputStream fileOutput = new FileOutputStream(file);
//this will be used in reading the data from the internet
InputStream inputStream = urlConnection.getInputStream();
//this is the total size of the file
int totalSize = urlConnection.getContentLength();
//variable to store total downloaded bytes
int downloadedSize = 0;
//create a buffer...
byte[] buffer = new byte[1024];
int bufferLength = 0; //used to store a temporary size of the buffer
//now, read through the input buffer and write the contents to the file
while ( (bufferLength = inputStream.read(buffer)) > 0 ) {
//add the data in the buffer to the file in the file output stream (the file on the sd card
fileOutput.write(buffer, 0, bufferLength);
//add up the size so we know how much is downloaded
downloadedSize += bufferLength;
//this is where you would do something to report the prgress, like this maybe
updateProgress(downloadedSize, totalSize);
}
//close the output stream when done
fileOutput.close();
//catch some possible errors...
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}*/
}
I think this is all I got out of the logcat:
logcat

You are declaring DownloadFile object but not initializing it.
private DownloadFile df;
df.Download(); // Throws NPE
Don't forget to initialize it.
private DownloadFile df = new DownloadFile();
df.Download();
EDIT:
Now you initialised the object and avoided NPE but this time you are getting a NetworkOnMainThreadException. After Honeycomb version, Android does not allow you to do network operations on main thread. You can use an AsyncTask to overcome this.