I am a beginner in android also in Java, many times I get confused with various Java implementations in android one of them is:
In the statements
FileOutputStream fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
what is fos in the above statement? It is obviously object of fileOutputStream but why is it not implemented as
FileOutputStream fos = new FileOutputStream(FILENAME, Context.MODE_PRIVATE);
If possible give me a simple example in java/android.
openFileOutput is a method of the Context that automatically creates a file output stream to your context's data folder.
If you use the constructor of FileOutputStream, you have to pass a full file path as the first argument, while the Context takes only the file name. For files that need not be accessible via file managers, use openFileOutput for saving the file and openFileInput for reading the file again.
Related
One part of my app needs to write a data file out.
I use getFilesDir() and it gives me a path like this (after adding a file name):
/data/data/com.casadelgato.zillaconfigdroid/files/Log.1378357559316.csv
I create a PrintWriter to the file, write a bunch of stuff to it, and close it.
No errors.
The problem is that I can't find the file anywhere on my Android device.
mention the file name in the path
FileOutputStream fos = context.openFileOutput(path,
Context.MODE_PRIVATE);
write the file into the stream...and you get the file by passing the same file name
FileInputStream openFileInput = context.openFileInput(path);
read the input stream
fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
fos.write(FirstNmstring.getBytes());
fos.close();
I used this code to store data in a file in internal memory of mobile. Just as I make another entry into my application, the existing record gets deleted. I want to add every entry that I enter. could any one help me out on this.
You can open the file for Append
fos = openFileOutput(FILENAME, Context.MODE_APPEND);
Everything you write to it will be appended at the end of the file.
I had created files i.e., txt files and stored values into it using openFileOutput fn. This function creates the txt file in the data/data/app_name/files folder.. Now i am trying to save a media files like .mp3 file to that data/data/app-name folder.. Is it possible to do so?
Thanks in advance.
fOut = openFileOutput("a.txt", MODE_PRIVATE);
OutputStreamWriter osw = new OutputStreamWriter(fOut);
String aa="hi";
osw.write(aa);
osw.flush();
osw.close();
This is how i had written a file to the data/data/app-name folder.. Nw i am trying to write a mp3 file but the osw.write(aa) accepts string or char array..
Context.openFileOutput() (reference) creates a FileOutputStream object which is capable of writing binary data (see write() method), so the answer is Yes, it can be used to write media files.
Android gives you getDir (I assume this means I would have myappspace/somedirectory) to create a directory in you application space. But how do you read or write to a file in that directory when android gives you an error if you have the path separator in the openFileOutput/Input call it gives you an error?
getDir returns a File object. To manipulate the directory and file structure, you continue to use File objects. For example
File dir = getDir("myDir", Context.MODE_PRIVATE);
File myFile = new File(dir, "myFile");
the openFileOutput simply returns a FileOutputStream based on some text criteria. All we have to do is create the object
FileOutputStream out = new FileOutputStream(myFile);
From here, you continue as normal.
String hello = "hello world";
out.write(hello.getBytes());
out.close();
FileInputStream would follow the same guidelines.
The point is that openFileInput() and openFileOutput() work with files in that directory directly so they don't need an absolute pathname.
EDIT: More accurately, they work with files in the directory returned by getFilesDir() rather than getDir() which is normally the package root.
If you want to create custom directories relative to getDir(), then you'll need to use classes/methods other than openFileInput() and openFileOutput() (such as using InputStream and OutputStream and relevant file 'reader' / 'writer' classes).
How to read and write strings in text file in android which is kept in raw folder and also how to clear contents of that file in android?
I have done this way and my "temp.txt" file is in /raw folder. But i am not getting any output in file. Also I am not getting any error for this.
FileOutputStream fos = openFileOutput("temp", Context.MODE_APPEND);
fos.write("Example Text in a file".getBytes());
fos.flush();
fos.close();
Try this one
Try to put file int /asset folder and then do operations