Develop Reference

FileNotFoundException although the text file exist (readable and writable)

I am trying to save data into text file in the internal storage and read it again .. It works fine in my mobile with android 11 but when i tried at android 8 it gives me this error
java.io.FileNotFoundException:/data/user/0/com.example.example/test.txt
(No such file or directory)
It appears at the first time to open the activity but i can clear it - as normal text - and write a new text and save it so the file is there and usable
here is read code
File path = getApplicationContext().getFilesDir();
File readFrom = new File(path, fileName);
byte[] content = new byte[(int) readFrom.length()];
try {
FileInputStream stream = new FileInputStream(readFrom);
stream.read(content);
return new String(content);
} catch (Exception e) {
e.printStackTrace();
return e.toString();
}
and this write code
public void writeToFile(String fileName, String content) {
File path = getApplicationContext().getFilesDir();
try {
FileOutputStream writer = new FileOutputStream(new File(path, fileName));
writer.write(content.getBytes());
writer.close();
} catch (IOException e) {
e.printStackTrace();
}
}

Android, how to Share an image file with messenger

Hello evrybody i'm tryng to share an image on messenger but i don't know why my code doesen't work, I've followed the official guide, https://developers.facebook.com/docs/messenger/android
someone can told me why doese'nt work?
public void sendMessage(){
Bitmap adv= takePic(HomeActivity.livelloCurrent.getNumeroLivello());
ByteArrayOutputStream bytes = new ByteArrayOutputStream();
adv.compress(Bitmap.CompressFormat.JPEG, 100, bytes);
File f = new File(Environment.getExternalStorageDirectory()+ File.separator + "temporary_file.jpg");
try {
f.createNewFile();
new FileOutputStream(f).write(bytes.toByteArray());
} catch (IOException e) {
e.printStackTrace();
}
String mimeType = "image/jpeg";
Intent sendIntent = new Intent();
sendIntent.setType(mimeType);
sendIntent.setAction(Intent.ACTION_SEND);
sendIntent.putExtra(Intent.EXTRA_STREAM,Uri.parse(Environment.getExternalStorageDirectory() + File.separator + "temporary_file.jpg"));
sendIntent.putExtra(Intent.EXTRA_TEXT, "<---MY TEXT--->.");
sendIntent.setPackage("com.facebook.orca");
try {
startActivity(sendIntent);
}
catch (android.content.ActivityNotFoundException ex) {
Toast.makeText(getApplicationContext(),"Please Install Facebook Messenger", Toast.LENGTH_LONG).show();
}
/** //withSDK-->// ShareToMessengerParams shareToMessengerParams = ShareToMessengerParams.newBuilder(ContentUri, mimeType).build();
MessengerUtils.shareToMessenger(this, REQUEST_CODE_SHARE_TO_MESSENGER, shareToMessengerParams);**/
}
Im sure that the file creation work cause i have tested it . in testing I get the following error from messenger "Sorry, Messenger was not able to process the file".
how can i solve ?

Replace:
Uri.parse(Environment.getExternalStorageDirectory() + File.separator + "temporary_file.jpg")
with:
Uri.fromFile(f)

create and open a sample pdf file while inside the application

I want to open a pdf file when inside the application(internal storage).I have the following code.But once adobe pdf is opened it shows a pop up error as " The document path is not valid".Is it not possible to only read a pdf file from inside the app? If not please let me know how can I copy it to the external storage.Thanks in advance
File file_source = new File(getApplicationContext().getFilesDir()+"/"+"sample.pdf");
String string = "Hello world!";
try
{
file_source.createNewFile();
FileOutputStream outputStream;
outputStream = openFileOutput("sample.pdf", Context.MODE_PRIVATE);
outputStream.write(string.getBytes());
outputStream.close();
if(file_source.exists())
{
Uri path = Uri.fromFile(file_source);
Intent intent1 = new Intent(Intent.ACTION_VIEW);
intent1.setDataAndType(path, "application/pdf");
intent1.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
try {
startActivity(intent1);
}
catch (ActivityNotFoundException e) {
Toast.makeText(this,
"No Application Available to View PDF",
Toast.LENGTH_SHORT).show();
Intent intent2 = new Intent(Intent.ACTION_VIEW);
startActivity(intent2);
}
}
else
{
Log.d("TAG","no file exists");
}
}
catch (FileNotFoundException e) {
Log.d("TAG","File not found");
}
catch (IOException ioe) {
Log.d("TAG","Exception while reading file" + ioe);
}

Files in the internal storage directory of your app are by default private to your application. Which means that no PDF-Reader app can read that file (since it doesn't run with your apps pid - no read permission is given).
You have to save that PDF with explicit reading permissions for other apps by using the Context.MODE_WORLD_READABLE flag.
Also use Context.openFileOutput() and Context.openFileInput() to read and write files in your internal directory . Don't hardcode paths like this, they might change.
You can copy the file from internal storage to external storage by below code.
try {
String file_name="inputpdf.pdf";
File tempfile = new File(directory, file_name);
FileInputStream inStream = new FileInputStream(tempfile);
//where ctx is your context (this)
FileOutputStream fos = ctx.openFileOutput("Outputpdf", ctx.MODE_WORLD_WRITEABLE|ctx.MODE_WORLD_READABLE);
byte[] buffer = new byte[1024];
int length;
//copy the file content in bytes
while ((length = inStream.read(buffer)) > 0){
fos.write(buffer, 0, length);
}
inStream.close();
fos.close();
} catch (FileNotFoundException e) {
e.printStackTrace();
}catch(Exception e){
e.printStackTrace();
}

Android open PDF : File not found

I try to open a PDF in my application.
First, I create the PDF like that :
String filename = Environment.getExternalStorageDirectory().toString()+"/mypdf.pdf";
File file = new File(filename);
try {
FileOutputStream bos = new FileOutputStream(file);
bos.write(Base64.decode(base64, 0));
bos.flush();
bos.close();
} catch (IOException e) {
Log.e(TAG, "IOError with PDF");
e.printStackTrace();
}
Intent intent = new Intent(this, PdfActivity.class);
intent.putExtra("file", filename);
startActivity(intent);
The file is well created and readable, I can open this with ESExplorer application.
This file is located in /storage/emulated/0/myfile.pdf
in the PdfActivity I try to open the PDF :
Bundle extras = getIntent().getExtras();
String url = extras.getString("file");
File file = new File(url);
try {
if (file.exists()) {
Uri path = Uri.parse(url);
Intent objIntent = new Intent(Intent.ACTION_VIEW);
objIntent.setDataAndType(path, "application/pdf");
objIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(objIntent);
} else {
Toast.makeText(this, "File NotFound", Toast.LENGTH_SHORT).show();
}
} catch (ActivityNotFoundException e) {
Toast.makeText(this, "No Viewer Application Found", Toast.LENGTH_SHORT).show();
} catch (Exception e) {
e.printStackTrace();
}
file.exists() return true, Intent start, but my PDF reader says : "File not found"
I've added read and write permissions on external storage.
Does someone have any idea why it can't access to my file ?

objIntent.setDataAndType(url, "application/pdf");
use above line in your second snippest also declare String url as a global variable hope it will help you if it will not work try to use hardcode value of file path and see is it working or not ?
and are you sure file is exist? check this scenario tooo :)

I found the solution.
I've replace the Uri like that:
Uri path = Uri.fromFile(file);
And it works!

Displaying PDF file with Adobe Reader

I created a class openPDF which takes a byte array as input and displays the PDF file with Adobe Reader. Code:
private void openPDF(byte[] PDFByteArray) {
try {
// create temp file that will hold byte array
File tempPDF = File.createTempFile("temp", ".pdf", getCacheDir());
tempPDF.deleteOnExit();
FileOutputStream fos = new FileOutputStream(tempPDF);
fos.write(PDFByteArray);
fos.close();
Intent intent = new Intent();
intent.setAction(Intent.ACTION_VIEW);
Uri uri = Uri.fromFile(tempPDF);
intent.setDataAndType(uri, "application/pdf");
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
} catch (IOException ex) {
String s = ex.toString();
ex.printStackTrace();
}
}
When I pass the intend , the error from adobe reader is "Invalid file path". I read all other posts related to downloading and viewing PDF in android but dint help much. Any suggestions?

I think the issue is that other apps have no access to the files in your app's private data area (like the cache dir).
Candidate solutions:
changing the file's mode to MODE_WORLD_READABLE so that it can be read by other apps
...
String fn = "temp.pdf";
Context c = v.getContext();
FileOutputStream fos = null;
try {
fos = c.openFileOutput(fn, Context.MODE_WORLD_READABLE);
fos.write(PDFByteArray);
} catch (FileNotFoundException e) {
// do something
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally {
if (fos!=null) {
try {
fos.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
Intent intent = new Intent();
intent.setAction(Intent.ACTION_VIEW);
String filename = c.getFilesDir() + File.separator + fn;
File file = new File(filename);
Uri uri = Uri.fromFile(file);
intent.setDataAndType(uri, "application/pdf");
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
...
or write the pdf file to the /sdcard partition.
you can use android.os.Environment API to get the path, and remember to add the permission to your app's AndroidManifest.xml file.
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
Regards
Ziteng Chen

I made this code to open an especific .pdf file existing in Dowloads folder with Adobe's application
File folder = new File(Environment.getExternalStorageDirectory(), "Download");
File pdf = new File(folder, "Test.pdf");
Uri uri = Uri.fromFile(pdf);
PackageManager pm = getPackageManager();
Intent intent = pm.getLaunchIntentForPackage("com.adobe.reader");
intent.setDataAndType(uri, "application/pdf");
startActivity(intent);
It works for me. So i guess your problem can be the temprorary file. Try to write the file to sdcard. To do this you will need add android.permission.WRITE_EXTERNAL_STORAGE to your AndroidManifest.xml.