CODEWITHSUNDEEP
javaandroid
Andy Roy D.
Andy Roy D.

Reputation: 1041

Initializing In Try/Catch

I have run into quite a snag while writing my app. Here is my issue:

I am trying to initialize the file input stream like so:

FileInputStream fis
fis = openFileInput(selectedFile);

Then put this 1 line later:

byte[] input = new byte[fis.available()];

Problem is both bits of code need try/catch statements and the second block cannot recognize fis because it was initialized within a try/catch. Here is my code:

private void openFile(String selectedFile) {
        String value = "";
        FileInputStream fis;
        try {
            fis = openFileInput(selectedFile);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }


        try {
            byte[] input = new byte[fis.available()];
        } catch (IOException e) {
            e.printStackTrace();
        }

What should I do? (Thanks in advance)

Upvotes: 0

Views: 597

Answers (3)

sinθ
sinθ

Reputation: 11493

Set the FileInputStream to a temporary value. null would be the best option, as in:

FileInputStream fis = null;

The reason for this is because if your try statement throws an error, then the fis will never me initialized. Then you'll have problems. If you don't exit the thing entirely, you should also add the statement after the try/catch blocks that tests if the value is null, just so that the program does not throw a null pointer exception.

So maybe something like:

if(fis == null) {
    return; // Which will just end the method.
}

Also might want to put the try/catches together (you should still declare the other stuff outside of the try, at least anything you plan on using directly later on in the code) but it just might be more efficient coding wise), as in:

FileInputStream fis = null;
byte[] input = null;
try {
    fis = openFileInput(selectedFile);
    input = new byte[fis.available()];
} catch (FileNotFoundException e) {
    e.printStackTrace();
} catch (IOException e) {
    e.printStackTrace();
}

Upvotes: 0

Andrew Cumming
Andrew Cumming

Reputation: 965

Set FileInputStream fis = null; when you first declare the variable.

You could also run your code like this because IOException will also catch the file not found exception.

String value = "";
FileInputStream fis;
try {
  fis = openFileInput(selectedFile);
  byte[] input = new byte[fis.available()];
} catch (IOException e) {
  e.printStackTrace();
}

Upvotes: 0

Evgeniy Dorofeev
Evgeniy Dorofeev

Reputation: 136002

The best approach in this situation is not to catch IOException at all.

private void openFile(String selectedFile) throws IOException {
        FileInputStream fis =  openFileInput(selectedFile);
        byte[] input = new byte[fis.available()];

It does not make sense to continue after you got FileNotFoundException

Upvotes: 1

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