Attempt to read from null array but array contains several filenames

Question

My app worked fine but after a reinstall I got the error that "attempt to get length of null array", while my dob folder is full of files that starting with pi_. Now I get files - Null.

Can anybody help what the error can be?

Thanks

File path = new File(Environment.getExternalStorageDirectory().toString() + "/dob");

    if (path.exists()) {
        Toast.makeText(this, "Dob folder exists", Toast.LENGTH_SHORT).show();
    } else {
        Toast.makeText(this, "Dob folder does not exist", Toast.LENGTH_SHORT).show();

    }

    File[] files = path.listFiles();

    if (files != null) {
        Toast.makeText(this, "files length: " + files.length, Toast.LENGTH_SHORT).show();

        piStarters = new String[files.length];
        int db = 0;

        for (File file : files) {
            Toast.makeText(this, ":" + file.toString() + ":", Toast.LENGTH_LONG).show();
            if (file.getName().startsWith("pi_")) {

                piStarters[db] = file.getName();
                Toast.makeText(this, "I need this (pistarter): " + piStarters[db], Toast
                        .LENGTH_SHORT)
                        .show();
                db++;
            }
        }
    } else {
        Toast.makeText(this, "files - Null ", Toast
                .LENGTH_SHORT).show();
    }

Manifest:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

have you implemented runtime permissions ? – Pavneet_Singh Aug 01 '17 at 17:16 — Pavneet_Singh, Aug 01 '17 at 17:16
yes my manifest file contains: – johnny cigar Aug 01 '17 at 17:18 — johnny cigar, Aug 01 '17 at 17:18
what is your android OS? – Pavneet_Singh Aug 01 '17 at 17:20 — Pavneet_Singh, Aug 01 '17 at 17:20
Android 6.0 is the version – johnny cigar Aug 01 '17 at 17:22 — johnny cigar, Aug 01 '17 at 17:22

Pavneet_Singh · Accepted Answer · 2017-08-01T17:23:49.647

1

You required to implement Requesting Permissions at Run Time to access the phone storage otherwise android OS marshmallow and above won't allow your app to access storage

So you need to implement the runtime permission model for storage access

Follow the link for an example

edited Aug 01 '17 at 17:23

answered Aug 01 '17 at 17:22

Pavneet_Singh

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i am glad that i could help, happy coding – Pavneet_Singh Aug 01 '17 at 17:24

Attempt to read from null array but array contains several filenames

1 Answers1