CODEWITHSUNDEEP
androidbufferedreaderfileinputstream
J2N
J2N

Reputation: 341

Android FileInputStream Code causes Crash

I've solved my own issue but I don't know why my first attempt didn't work and I was hoping someone could tell me why. I was also hoping if someone could tell me if my final solution is a "good" one or not (by this I mean, is it efficient)?

This was my first attempt at reading an input file I had previously created:

private byte[] mInputData;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.second_view);

    Intent myIntent = getIntent();

    mFilename = myIntent.getStringExtra("FILENAME");
    mSplitSeq = myIntent.getStringExtra("SPLIT_SEQ");

    try {
        fis = openFileInput(mFilename);
        fis.read(mInputData);
        fis.close();
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

This is something I found online that actually worked:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.second_view);

    Intent myIntent = getIntent();

    mFilename = myIntent.getStringExtra("FILENAME");
    mSplitSeq = myIntent.getStringExtra("SPLIT_SEQ");

    try {
        fis = openFileInput(mFilename);
        BufferedReader reader = new BufferedReader(new InputStreamReader(fis));
        String line = null, input="";
        while ((line = reader.readLine()) != null)
            mTimeStr += line;
        reader.close();
        fis.close();
        //fis.read(mInputData);
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }

The error I received with my first implementation was a NullPointerException when calling the fis.read(mInputData) function.

Upvotes: 0

Views: 1293

Answers (1)

MattDavis
MattDavis

Reputation: 5178

I'm pretty sure it's because mInputData is never initialized. You'd need a line in there like mInputData = new byte[1000];. Instead, you're telling read() to give data to a reference that equals null, a NullPointerException.

Upvotes: 3

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