CODEWITHSUNDEEP
javaandroid
zoltish
zoltish

Reputation: 2302

FileOutputStream(FileDescriptor) that overwrites instead of appending data?

Im writing to a file through a FileOutputStream that is opened via its constructor taking a FileDescriptor.

My desired behavior: When I write to the file I want that to be the only content of it. E.g. writing "Hello" should result in the file containing just "Hello".

Actual behavior: Each time I write something, it is simply appeneded. E.g. in the above example I will get "HelloHello".

How can I open a FileOutputStream like Im doing, and have it not be in append mode?

Note: I am forced to use a FileDescriptor.

Upvotes: 5

Views: 4845

Answers (4)

Liam
Liam

Reputation: 669

According to the ContentProvider.java file documentation, you can use "rwt" mode to read and write in file in truncating it.

ParcelFileDescriptor pfd = context.getContentResolver.openFileDescriptor(uri, "rwt");
FileOutputStream fos = new FileOutputStream(pfd.getFileDescriptor());

@param mode Access mode for the file. May be "r" for read-only access, "rw" for read and write access, or "rwt" for read and write access that truncates any existing file.

Hope this help despite that the question was posted a long time ago.

Upvotes: 2

António Paulo
António Paulo

Reputation: 351

FileOutputStream outputStream;

    try {

        outputStream = openFileOutput("your_file", Context.MODE_PRIVATE);
        //Context.MODE_PRIVATE -> override / MODE_APPEND -> append
        outputStream.write("your content");
        outputStream.close();
    } catch (Exception e) {
        e.printStackTrace();
    }

Upvotes: 0

Hari Krishna
Hari Krishna

Reputation: 3548

FileOutputStream(File file, boolean append)

Make the argument append to false, so it overrides the existing data everytime when you call.

https://docs.oracle.com/javase/7/docs/api/java/io/FileOutputStream.html#FileOutputStream(java.io.File,%20boolean)

Upvotes: 0

The Roy
The Roy

Reputation: 2208

If you use FileOutoutStream then the ctor provides an option for you to specify whether you want to open the file to append or not. Set it to false and it will work.

    OutputStream out = null;
    try {
        out = new FileOutputStream("OutFile", false);
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }

Upvotes: 0

Related Questions