Develop Reference

How to write and constantly update a text file in Android

I have a camera that I am grabbing values pixel-wise and I'd like to write them to a text file. The newest updates for Android 12 requires me to use storage access framework, but the problem is that it isn't dynamic and I need to keep choosing files directory. So, this approach it succesfully creates my files but when writting to it, I need to specifically select the dir it'll save to, which isn't feasible to me, as the temperature is grabbed for every frame and every pixel. My temperature values are in the temperature1 array, I'd like to know how can I add consistently add the values of temperature1 to a text file?
EDIT: I tried doing the following to create a text file using getExternalFilesDir():
private String filename = "myFile.txt";
private String filepath = "myFileDir";
public void onClick(final View view) {
switch (view.getId()){
case R.id.camera_button:
synchronized (mSync) {
if (isTemp) {
tempTureing();
fileContent = "Hello, I am a saved text inside a text file!";
if(!fileContent.equals("")){
File myExternalFile = new File(getExternalFilesDir(filepath), filename);
FileOutputStream fos = null;
try{
fos = new FileOutputStream(myExternalFile);
fos.write(fileContent.getBytes());
} catch (Exception e) {
e.printStackTrace();
}
Log.e("TAG", "file: "+myExternalFile);
}
isTemp = false;
//Log.e(TAG, "isCorrect:" + mUVCCamera.isCorrect());
} else {
stopTemp();
isTemp = true;
}
}
break;
I can actually go all the way to the path /storage/emulated/0/Android/data/com.MyApp.app/files/myFileDir/ but strangely there is no such file as myFile.txt inside this directory, how come??

Working Solution:
public void WriteToFile(String fileName, String content){
File path = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS);
File newDir = new File(path + "/" + fileName);
try{
if (!newDir.exists()) {
newDir.mkdir();
}
FileOutputStream writer = new FileOutputStream(new File(path, filename));
writer.write(content.getBytes());
writer.close();
Log.e("TAG", "Wrote to file: "+fileName);
} catch (IOException e) {
e.printStackTrace();
}
}

Java - Pass a variable from user input to another java file

I am new to Java and I have a project to do, so I have a java file and the user have to choose from a listing of files in a directory. The input from user is saved in a variable (fileName). I want to use that variable in another java file for doing some other work. I searched online but didn't find any solution that works for me. Probably I've done something wrong.
code of the first file:
public class Director {
private static void copyFileUsingStream(File source, File dest) throws IOException {
InputStream is = null;
OutputStream os = null;
try {
is = new FileInputStream(source);
os = new FileOutputStream(dest);
byte[] buffer = new byte[1024];
int length;
while ((length = is.read(buffer)) > 0) {
os.write(buffer, 0, length);
}
} finally {
is.close();
os.close();
}
}
public static void main(String[] args) throws IOException {
// Creates an array in which we will store the names of files and directories
String[] pathnames;
// Creates a new File instance by converting the given pathname string
// into an abstract pathname
File f = new File("C:\\Users\\miltos\\Desktop\\polimesa\\available_videos");
// Populates the array with names of files and directories
pathnames = f.list();
System.out.println("Files in the directory:");
// For each pathname in the pathnames array
for (String pathname : pathnames) {
// Print the names of files and directories
System.out.println(pathname);
}
Scanner myObj = new Scanner(System.in); // Create a Scanner object
System.out.println("Enter file name");
String fileName = myObj.nextLine();
File source = new File("C:\\Users\\miltos\\Desktop\\polimesa\\available_videos\\" + fileName);
File dest = new File("C:\\Users\\miltos\\Desktop\\polimesa\\raw_videos\\" + fileName);
copyFileUsingStream(source, dest);
}
}
code of the second file that i want to use the input:
public class TestFFMpeg {
static Logger log = LogManager.getLogger(TestFFMpeg.class);
public static void main(String[] args) {
FFmpeg ffmpeg = null;
FFprobe ffprobe = null;
try {
log.debug("Initialising FFMpegClient");
ffmpeg = new FFmpeg("C:\\Users\\miltos\\ffmpeg\\bin\\ffmpeg.exe");
ffprobe = new FFprobe("C:\\Users\\miltos\\ffmpeg\\bin\\ffprobe.exe");
} catch (IOException e) {
e.printStackTrace();
}
log.debug("Creating the transcoding");
FFmpegBuilder builder = new FFmpegBuilder()
.setInput("C:\\Users\\miltos\\Desktop\\polimesa\\raw_videos\\" + filename) //updated
.addOutput("C:\\Users\\miltos\\Desktop\\polimesa\\videos\\" + filename) //updated
.setVideoBitRate(200000)
.done();
log.debug("Creating the executor");
FFmpegExecutor executor = new FFmpegExecutor(ffmpeg, ffprobe);
log.debug("Starting the transcoding");
// Run a one-pass encode
executor.createJob(builder).run();
log.debug("Transcoding finished");
}
}

I created a variable names filename in class second also, which you will pass from the class one , while creating an object of class second like
TestFFMpeg obj = new TestFFMpeg();
obj.methodInSecondClass(filename);
Second Class :
public class TestFFMpeg {
static Logger log = LogManager.getLogger(TestFFMpeg.class);
public void methodInSecondClass(String filename){
FFmpeg ffmpeg = null;
FFprobe ffprobe = null;
try {
log.debug("Initialising FFMpegClient");
ffmpeg = new FFmpeg("C:\\Users\\miltos\\ffmpeg\\bin\\ffmpeg.exe");
ffprobe = new FFprobe("C:\\Users\\miltos\\ffmpeg\\bin\\ffprobe.exe");
} catch (IOException e) {
e.printStackTrace();
}
log.debug("Creating the transcoding");
FFmpegBuilder builder = new FFmpegBuilder()
.setInput("C:\\Users\\miltos\\Desktop\\polimesa\\available_videos\\"+filename) //this is where i want the same variable
.addOutput("C:\\Users\\miltos\\Desktop\\polimesa\\videos\\"+filename) //this is where i want the same variable
.setVideoBitRate(200000)
.done();
log.debug("Creating the executor");
FFmpegExecutor executor = new FFmpegExecutor(ffmpeg, ffprobe);
log.debug("Starting the transcoding");
// Run a one-pass encode
executor.createJob(builder).run();
log.debug("Transcoding finished");
}
}

File Not Found Exception : Open failed:ENOENT

I am new for android, Im downloading image from URL and set in listView. Its working some mobile and not creating file/directory in some mobile.
Its throw error like:
java.io.FileNotFoundException: /storage/emulated/0/.tam/veg.png: open failed: ENOENT (No such file or directory)
I don't know why its throw error like this some mobile. I want to create directory all type of mobile. Please anyone help me.
Here my code:
public class ImageStorage {
public static String saveToSdCard(Bitmap bitmap, String filename) {
String stored = null;
File sdcard = Environment.getExternalStorageDirectory();
File folder = new File(sdcard.getAbsoluteFile(), ".tam");//the dot makes this directory hidden to the user
folder.mkdir();
File file = new File(folder.getAbsoluteFile(), filename) ;
if (file.exists())
return stored ;
try {
FileOutputStream out = new FileOutputStream(file);
bitmap.compress(Bitmap.CompressFormat.PNG, 90, out);
out.flush();
out.close();
stored = "success";
} catch (Exception e) {
e.printStackTrace();
}
return stored;
}
public static File getImage(String imagename) {
File mediaImage = null;
try {
String root = Environment.getExternalStorageDirectory().getAbsolutePath();
File myDir = new File(root);
if (!myDir.exists())
return null;
mediaImage = new File(myDir.getPath() + "/.tam/"+imagename);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return mediaImage;
}
public static File checkifImageExists(String imagename) {
File file = ImageStorage.getImage("/" + imagename);
if (file.exists()) {
return file;
} else {
return null;
}
}
public static String getImageName(String value){
String getName[] = value.split("/");
return getName[4];
}
}
Below path not in all mobile:
/storage/emulated/0/
Thanks in advance!!

Maybe u should check if there's external storage in the mobile before u use this path
public String getDir(Context context) {
String checkPath = null;
if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())
|| !Environment.isExternalStorageRemovable()) {
checkPath = Environment.getExternalStorageDirectory().getPath();
} else {
checkPath = context.getCacheDir().getPath();
}
return checkPath;
}

How to set the save path for a file chosen in filechooser JavaFX

I searched around but couldn't find nothing on this.
I would like to set the save (destination) path for a file selected in Filechooser. For example, I selected a picture called 'test.jpg', I would like for this 'test.jpg' to be saved to C:\blah\blah\blah\Pictures. How can I pull this off?
So far the code I have
public void OnImageAddBeer(ActionEvent event){
FileChooser fc = new FileChooser();
//Set extension filter
fc.getExtensionFilters().addAll(new ExtensionFilter("JPEG Files (*.jpg)", "*.jpg"));
File selectedFile = fc.showOpenDialog(null);
if( selectedFile != null){
}
}

All you need to do is copy the content inside the file choose in wherever you want, try something like this:
if(selectedFile != null){
copy(selectedFile.getAbsolutePath(), "C:\\blah\\blah\\blah\\Pictures\\test.jpg");
}
and the method copy:
public void copy(String from, String to) {
FileReader fr = null;
FileWriter fw = null;
try {
fr = new FileReader(from);
fw = new FileWriter(to);
int c = fr.read();
while(c!=-1) {
fw.write(c);
c = fr.read();
}
} catch(IOException e) {
e.printStackTrace();
} finally {
close(fr);
close(fw);
}
}
public static void close(Closeable stream) {
try {
if (stream != null) {
stream.close();
}
} catch(IOException e) {
//...
}
}
Basically copy just copy the content of the file located in from inside a new file located at to.

Try this:
String fileName = selectedFile.getName();
Path target = Paths.get("c:/user/test", fileName);
Files.copy(selectedFile.toPath(), target);

Add this statement if you want to set the destination path:
fc.setInitialDirectory(new File(System.getProperty("user.home") + "\\Pictures"));

Take this:
String dir = System.getProperty("user.dir");
File f = new File(dir + "/abc/def");
fc.setInitialDirectory(f);

how to open pdf file in project folder using vaadin code?

I have a PDF in project location how to open pdf file
my project name is MyProject
My pdf is under project folder
MyProject\Pdf\test.pdf how to open my pdf file
I need to open pdf file in the project location
I have tried below code
final Button viewBtn= new Button("View Policy Schedule");
viewBtn.addClickListener( newButton.ClickListener() public void buttonClick(ClickEvent event) {
Window window = new Window();
window.setResizable(true);
window.setCaption("Claim Form Covering Letter PDF");
window.setWidth("800");
window.setHeight("600");
window.setModal(true);
window.center();
final String filepath = "Pdf//test.pdf";
File f = new File(filepath);
System.out.println(f.getAbsolutePath());
Path p = Paths.get(filepath);
String fileName = p.getFileName().toString();
StreamResource.StreamSource s = new StreamResource.StreamSource() {
/**
*
*/
private static final long serialVersionUID = 9138325634649289303L;
public InputStream getStream() {
try {
File f = new File(".");
System.out.println(f.getCanonicalPath());
FileInputStream fis = new FileInputStream(f);
return fis;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
};
StreamResource r = new StreamResource(s, fileName);
Embedded e = new Embedded();
e.setSizeFull();
e.setType(Embedded.TYPE_BROWSER);
r.setMIMEType("application/pdf");
e.setSource(r);
window.setContent(e);
UI.getCurrent().addWindow(window);
}
});
It's not working I have got a file not found exception

Move the PDF so you can read it from the classpath. If you are using Maven put it in src/main/resources. Otherwise put it in some package.
You can then read it using getResourcesAsStream() method of java.lang.class.
InputStream in = this.getClass().getResourcesAsStream("/test.pdf"); //classpath root
InputStream in = this.getClass().getResourcesAsStream("/my/package/name/test.pdf"); //from some package
Updated
final Button viewBtn= new Button("View Policy Schedule");
viewBtn.addClickListener( newButton.ClickListener()
public void buttonClick(ClickEvent event) {
Window window = new Window();
window.setResizable(true);
window.setCaption("Claim Form Covering Letter PDF");
window.setWidth("800");
window.setHeight("600");
window.setModal(true);
window.center();
StreamResource.StreamSource s = new StreamResource.StreamSource() {
public InputStream getStream() {
try {
return this.getClass().getResourcesAsStream("/test.pdf");
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
};
StreamResource r = new StreamResource(s, fileName);
Embedded e = new Embedded();
e.setSizeFull();
e.setType(Embedded.TYPE_BROWSER);
r.setMIMEType("application/pdf");
e.setSource(r);
window.setContent(e);
UI.getCurrent().addWindow(window);
}
});