background thread not responding android asynctask

Question

I am trying to traverse all the folders in the file system. and I want to index all the traversed files. When I am trying to do the indexing with SQLite db, the app doesn't respond. What is the way to get it working?

  private class StartIndexing extends AsyncTask<File, String, String>{


            @Override
            protected String doInBackground(File... params) {
                String indexDone="0";
                File file=params[0];
                indexIn(file);

                indexDone="Async Done";
                return indexDone;
            }

            protected void indexIn(File folder){
                File[] dirs=folder.listFiles();

                for(File val:dirs){

                    if(val.isDirectory()){
                        new StartIndexing().executeOnExecutor(THREAD_POOL_EXECUTOR,val);

                        count++;
                    }
                    else{
                        DBoperation(val);
                        filecount++;
                    }

                }


            }

You shouldn't be doing a db insert every time you find a file. Instead, save the info in a data structure, like a List, then dump it to the db when the scan is complete. — Mike M., Jul 24 '14 at 09:35
Create a POJO class with only the file data you need. Create a List of those objects. Instead of calling `DBoperation(val)`, add an instance of your POJO for each file to the List. When it's done scanning, insert the List's data into the db. [Check this post](http://stackoverflow.com/questions/11328350/how-to-speed-up-large-data-insertion-in-database-sqlite-in-android-application) for tips on inserting large amounts of data. — Mike M., Jul 24 '14 at 10:00
I forgot to mention, an `AsyncTask` might not be the best solution if you're traversing a sizable hierarchy, as they are meant for short-lived operations. You might look into `Service`s, specifically `IntentService`s. — Mike M., Jul 24 '14 at 10:20

score 0 · Answer 1 · answered Jul 24 '14 at 09:34

0

Check your logcat it should tell you where the problem occurs. Make sure the objects you use are not null. For instance, the 'params'.

Another possibility file.listFiles() will return null if that file is empty, you'll get NPE when try to use it

answered Jul 24 '14 at 09:34

Guster

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code works in emulator so i dont get an error in logcat. but fails on device – user2820823 Jul 24 '14 at 09:36
the file system in emulator and device is different, highly possible some files are empty, just my guess – Guster Jul 24 '14 at 09:43
It wont matter if files are empty.I am just inserting their path into the db. – user2820823 Jul 24 '14 at 09:45
It does, File[] dirs=folder.listFiles(); for(File val:dirs){...}, if dirs is null, you'll get null pointer ex – Guster Jul 24 '14 at 09:47
It will crash, thats your main issue isn't it? – Guster Jul 24 '14 at 09:50
crashing is my issue. but It wont crash if the directory is null, thats my point. – user2820823 Jul 24 '14 at 09:54
I'm just making assumption based on your code. If you're not doing any exception catching there, chances are yes for(file : ) will definitely crash the app – Guster Jul 24 '14 at 10:01
No. It wont crash. The loop will only loop until there are files in the array. If the array comes out to be empty then it wont loop and execute the remaining code. – user2820823 Jul 24 '14 at 10:05

background thread not responding android asynctask

1 Answers1