Android-Spinner异步下载无法正常运行

Question

Upon activation of any button in the spinner the progress dialog comes up but nothing happens. I had this working perfectly with buttons but don't understand what is wrong here when transitioning to spinners. Anyone spot the reason why the download doesn't start up correctly?

public class SpinnerActivity extends Activity {

public static final int DIALOG_DOWNLOAD_PROGRESS = 0;
private ProgressDialog mProgressDialog;

Spinner spDownloadFrom;
private ArrayAdapter<CharSequence> spinnerArrayAdapter;
String url[] = {"http://www.becker.cl/bases.pdf",
        "http://www.pitt.edu/documents/campusmap0607.pdf", "http://www.aara.ca/reg3317/web_page_doc.pdf",
        "www.dataprotection.ie/documents/guidance/GuidanceFinance.pdf", "http://www.fmbb2012.com/JumpingQualifica1.pdf",
        "http://www.consulatdumaroc.ca/coloniefh22012.pdf", "http://www.rgrdlaw.com/media/cases/140_Complaint.pdf" };
String name[] = { "bases.pdf", "campusmap0607.pdf", "web_page_doc.pdf", "GuidanceFinance.pdf",
        "JumpingQualifica1.pdf", "coloniefh22012.pdf", "140_Complaint.pdf", };

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

    mProgressDialog = new ProgressDialog(SpinnerActivity.this);
    mProgressDialog.setMessage("Please be patient, file downloading...");
    mProgressDialog.setIndeterminate(false);
    mProgressDialog.setMax(100);
    mProgressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);

    spDownloadFrom = (Spinner) findViewById(R.id.Spinner01);

    spinnerArrayAdapter = new ArrayAdapter<CharSequence>(this,
            android.R.layout.simple_spinner_item, name);
    spinnerArrayAdapter
            .setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spDownloadFrom.setAdapter(spinnerArrayAdapter);

    spDownloadFrom.setOnItemSelectedListener(new SpinnerListener(
            spDownloadFrom));
}

public class SpinnerListener implements OnItemSelectedListener {
    Spinner sp;

    public SpinnerListener(View v) {
        sp = (Spinner) findViewById(v.getId());
    }

    @Override
    public void onItemSelected(AdapterView<?> parent, View v, int arg2,
            long arg3) {
        // Call to download class
        startDownload(arg2);


    }

    @Override
    public void onNothingSelected(AdapterView<?> arg0) {
        // TODO Auto-generated method stub

    }
}

private void startDownload(Integer... url) {
    DownloadFile downloadFile = new DownloadFile();
    downloadFile.execute();

}

class DownloadFile extends AsyncTask<String, Integer, String> { // put your
                                                                // download
                                                                // code

    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        mProgressDialog.show();
    }

    @Override
    protected void onProgressUpdate(Integer... progress) {
        super.onProgressUpdate(progress);
        mProgressDialog.setProgress(progress[0]);
    }

    @Override
    protected String doInBackground(String... aurl) {
        try {

            URL url = new URL(aurl[0]);
            URLConnection connection = url.openConnection();

            connection.connect();
            int fileLength = connection.getContentLength();
            int tickSize = 2 * fileLength / 100;
            int nextProgress = tickSize;

            Log.d(

            "ANDRO_ASYNC", "Lenght of file: " + fileLength);

            InputStream input = new BufferedInputStream(url.openStream());

            String path = Environment.getExternalStorageDirectory()
                    + "/Android/Data/"
                    + getApplicationContext().getPackageName() + "/files/" + name;
            File file = new File(path);
            file.mkdirs();
            File outputFile = file;

            OutputStream output = new FileOutputStream(outputFile);

            byte data[] = new byte[1024 * 1024];
            long total = 0;
            int count;
            while ((count = input.read(data)) != -1) {
                total += count;
                if (total >= nextProgress) {
                    nextProgress = (int) ((total / tickSize + 1) * tickSize);
                    this.publishProgress((int) (total * 100 / fileLength));
                }
                output.write(data, 0, count);
            }

            output.flush();
            output.close();
            input.close();
            mProgressDialog.dismiss();

        } catch (Exception e) {
        }
        return null;
    }

    protected void onProgressUpdate(String... progress) {
        Log.d("Downloading", progress[0]);

    }

    @Override
    protected void onPostExecute(String unused) {

        File file = new File(Environment.getExternalStorageDirectory()
                + "/Android/Data/"
                + getApplicationContext().getPackageName()
                + "/files/" + name);
        Intent testIntent = new Intent(Intent.ACTION_VIEW);
        testIntent.setType("application/pdf");
        Intent intent = new Intent();
        intent.setAction(Intent.ACTION_VIEW);
        Uri uri = Uri.fromFile(file);
        intent.setDataAndType(uri, "application/pdf");
        try {
            startActivity(intent);
        } catch (ActivityNotFoundException e) {
            Toast.makeText(SpinnerActivity.this,
                    "No Application Available to View PDF",
                    Toast.LENGTH_LONG).show();
        }
    }
}
}

Answer 1

In your startDownload method, you are passing in url , which is an array of String type. In doInBackground of your AsyncTask , you are only using the first index of url , which you have set as "" , so you're passing in an empty String .

To pass in the URL you are expecting, change the startDownload method to accept an int value. Then in the onItemSelected method, pass in the position, which you have named as arg2 (The parameter names should be parent, view, position, and id, in that order. Easier to understand what they mean). Then when you call downloadFile.execute , pass in url[position] .

Edit

Change your download method to like this:

private void startDownload(int position) {
    DownloadFile downloadFile = new DownloadFile();
    downloadFile.execute(url[position]);
}

That should give you the expected results, assuming the URLs you are using are valid. Also, your dialog isn't going away because you forgot to call mProgressDialog.dismiss() in onPostExecute .