I have a logging class for writing into a file in the app's internal storage space. Whenever the log file exceeds the size limit. For clearing the contents, I am closing the current FileOutputStream and creating a new stream with Write mode and closing it. Is there a way better way for accomplishing this:
public final void clearLog() throws IOException {
synchronized (this) {
FileOutputStream fos = null;
try {
// close the current log file stream
mFileOutputStream.close();
// create a stream in write mode
fos = mContext.openFileOutput(
LOG_FILE_NAME, Context.MODE_PRIVATE);
fos.close();
// create a new log file in append mode
createLogFile();
} catch (IOException ex) {
Log.e(THIS_FILE,
"Failed to clear log file:" + ex.getMessage());
} finally {
if (fos != null) {
fos.close();
}
}
}
}
You could also overwrite your file with nothing.
UPDATE:
There seems to be a better option with getFilesDir () Have a look at this question How to delete internal storage file in android?
Write empty data into file:
String string1 = "";
FileOutputStream fos ;
try {
fos = new FileOutputStream("/sdcard/filename.txt", false);
FileWriter fWriter;
try {
fWriter = new FileWriter(fos.getFD());
fWriter.write(string1);
fWriter.flush();
fWriter.close();
} catch (Exception e) {
e.printStackTrace();
} finally {
fos.getFD().sync();
fos.close();
}
} catch (Exception e) {
e.printStackTrace();
}
In this code:
fos = new FileOutputStream("/sdcard/filename.txt", false);
FALSE - for write new content. If TRUE - text append to existing file.
public void writetofile(String text){ // text is a string to be saved
try {
FileOutputStream fileout=openFileOutput("mytextfile.txt", false); //false will set the append mode to false
OutputStreamWriter outputWriter=new OutputStreamWriter(fileout);
outputWriter.write(text);
outputWriter.close();
readfromfile();
Toast.makeText(getApplicationContext(), "file saved successfully",
Toast.LENGTH_LONG).show();
}catch (Exception e) {
e.printStackTrace();
}
}
Related
I write the file to the directory and after 1-2 seconds I remove the battery from the device. After writing, I open the file and output it to the log in order to make sure that it is recorded. So it is recorded successfully. But after turning on the device I open the file and it is empty.
What could be the reason?
Used to read and write FileOutputStream/FileInputStream, FileWriter/FileReader, FileUtils from Apache Commons IO.
public static void storeForReversal(XmlTag sourceTag_TrnAddRq) {
String toStore = sourceTag_TrnAddRq.buildXmlString();
File sdFile = new File(getFilesDir(), "reversal");
try {
FileUtils.writeStringToFile(sdFile, toStore, "US-ASCII");
} catch (IOException e) {
ZLog.add(MyApplication.TAG, "ERROR store file Reversal: ", e);
}
}
public static String restoreForReversal() {
String result = "";
File sdFile = new File(getFilesDir(), "reversal");
try {
result = FileUtils.readFileToString(sdFile, "US-ASCII");
} catch (IOException e) {
ZLog.add(MyApplication.TAG, "ERROR restore file Reversal: ", e);
}
return result;
}
Device File Explorer
To ensure that information is saved in a file during an emergency power off, you need to use fo.getFD().sync():
try (FileOutputStream fo = new FileOutputStream(sdFile)) {
fo.write(text.getBytes());
fo.flush();
fo.getFD().sync();
} catch (IOException e) {
Log.e(TAG, "");
}
I am attempting to save to long term file storage in android as well as create a new file in the process. This code keeps crashing with minimal helpful logcat.
Thanks.
public void save (String text) {
FileOutputStream fos = null;
try {
fos = openFileOutput("logfile.txt", MODE_PRIVATE);
fos.write(text.getBytes());
} catch (FileNotFoundException e)
{} catch (IOException e) {
e.printStackTrace();
} finally {
if(fos != null)
{
try {
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
I expect it to create a file called logfile.txt and print text to it but instead it crashes.
Try something alike this, in order to get a FileOutputStream from a File in tmp / private storage:
// File file = File.createTempFile("logfile", ".txt");
File file = new File(getFilesDir(), "logfile.txt");
FileOutputStream fos = new FileOutputStream(file);
The resulting path should be /data/data/tld.domain.package/files/logfile.txt.
file.getAbsolutePath() has the value.
See Save a file on internal storage.
I'm relatively new to android, and I'm trying to modify an android app such that it downloads a profile picture (preferably in PNG) from a URL, and saves it in the com.companyName.AppName.whatever/files. It should be noted that the app was initially created in Unity, and just built and exported.
Here's my initial code:
URL url = null;
try {
url = new URL(playerDO.getProfileURL());
} catch (MalformedURLException e) {
e.printStackTrace();
}
InputStream input = null;
try {
input = url.openStream();
} catch (IOException e) {
e.printStackTrace();
}
String fileName = playerDO.getId() + ".png";
FileOutputStream outputStream = null;
try {
outputStream = openFileOutput(fileName, Context.MODE_PRIVATE);
byte[] buffer = new byte[256];
int bytesRead = 0;
while ((bytesRead = input.read(buffer, 0, buffer.length)) >= 0) {
outputStream.write(buffer, 0, bytesRead);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
outputStream.close();
input.close();
} catch (IOException e) {
e.printStackTrace();
}
}
EDIT: Here's my other code, as suggested by #Ashutosh Sagar
InputStream input = null;
Bitmap image = null;
try {
input = url.openStream();
image = BitmapFactory.decodeStream(input);
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
String fileName = playerDO.getId() + ".png";
FileOutputStream outputStream = null;
File myDir = getFilesDir();
try {
Log.wtf("DIRECTORY", myDir.toString());
File imageFile = new File(myDir, fileName);
if (!imageFile.exists()){
imageFile.createNewFile();
Log.wtf("ANDROID NATIVE MSG: WARN!", "File does not exist. Writing to: " + imageFile.toString());
}
outputStream = new FileOutputStream(imageFile, false);
image.compress(Bitmap.CompressFormat.PNG, 90, outputStream);
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
outputStream.close();
input.close();
} catch (IOException e) {
e.printStackTrace();
Log.wtf("AWWW CRAP", e.toString());
}
}
(It doesn't write either).
Unfortunately, I've had several problems with this. My primary issue is that when it (on the cases that it does) runs, it actually doesn't save anything. I'll go and check com.companyName.AppName.whatever/files directory only to find no such .png file. I will also need it to overwrite any existing files of the same name, which is hard to check when it doesn't work.
My secondary issue is that it fails to take into account delays in internet connection. Although I've put in enough try-catch clauses to stop it from crashing (as it used to), the end result is that it also doesn't save.
How can I improve upon this? Anything I'm missing?
EDIT:
Printing out the directory reveals it should be in:
/data/user/0/com.appName/files/5965e9e4a0f0463853016e2b.png
However, using ES File explorer, the only thing remotely close to that is
emulated/0/Android/data/com.appName/files/
Are they the same directory?
try this first get bitmap image from url
Bitmap mIcon11 = null;
try {
InputStream in = new java.net.URL(url).openStream();
mIcon11 = BitmapFactory.decodeStream(in);
} catch (Exception e) {
Log.d("Error", e.getStackTrace().toString());
}
and to save bitmap image please check the ans of GoCrazy
Try this
void getImage(String string_url)
{
//Generate Bitmap from URL
URL url_value = new URL(string_url);
Bitmap image =
BitmapFactory.decodeStream(url_value.openConnection().getInputStream());
//Export File to local Directory
OutputStream stream = new FileOutputStream("path/file_name.png");
/* Write bitmap to file using JPEG or PNG and 80% quality hint for JPEG. */
bitmap.compress(CompressFormat.PNG, 80, stream);
stream.close();
}
Like in the method i have attached i have used practiceData.txt i am getting same results while using just practiceData in file constructor so is it ok to use file without any extension or txt is better?
private void saveData(String data) {
File file = new File(this.getFilesDir(), "practiceData.txt");
FileOutputStream fileOutputStream = null;
try {
fileOutputStream = new FileOutputStream(file);
fileOutputStream.write(data.getBytes());
saveStatus = "Data was successfully saved.";
} catch (java.io.IOException e) {
e.printStackTrace();
saveStatus = "Error occurred: " + e.toString();
} finally {
if (fileOutputStream != null) {
try {
fileOutputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
It doesn't matter what file extension you use, it just tells the OS how to open the file. So yes, you can use no extension and it will work just as well.
If you intend the file to be opened manually via another application, it may be helpful to use a standard extension however.
How can I delete the content of a file in Java?
How about this:
new RandomAccessFile(fileName).setLength(0);
new FileOutputStream(file, false).close();
You could do this by opening the file for writing and then truncating its content, the following example uses NIO:
import static java.nio.file.StandardOpenOption.*;
Path file = ...;
OutputStream out = null;
try {
out = new BufferedOutputStream(file.newOutputStream(TRUNCATE_EXISTING));
} catch (IOException x) {
System.err.println(x);
} finally {
if (out != null) {
out.flush();
out.close();
}
}
Another way: truncate just the last 20 bytes of the file:
import java.io.RandomAccessFile;
RandomAccessFile file = null;
try {
file = new RandomAccessFile ("filename.ext","rw");
// truncate 20 last bytes of filename.ext
file.setLength(file.length()-20);
} catch (IOException x) {
System.err.println(x);
} finally {
if (file != null) file.close();
}
May problem is this leaves only the head I think and not the tail?
public static void truncateLogFile(String logFile) {
FileChannel outChan = null;
try {
outChan = new FileOutputStream(logFile, true).getChannel();
}
catch (FileNotFoundException e) {
e.printStackTrace();
System.out.println("Warning Logfile Not Found: " + logFile);
}
try {
outChan.truncate(50);
outChan.close();
}
catch (IOException e) {
e.printStackTrace();
System.out.println("Warning Logfile IO Exception: " + logFile);
}
}
Open the file for writing, and save it. It delete the content of the file.
try {
PrintWriter writer = new PrintWriter(file);
writer.print("");
writer.flush();
writer.close();
}catch (Exception e)
{
}
This code will remove the current contents of 'file' and set the length of file to 0.