How to download file from server using http in Android

Question

I'm trying to download file from URL using HttpURLConnection in Android.

First I added textviews programmatically and set a listener to each textviews to download a file. Below is that code.

for(Element ele: elements){
            final TextView attachItem = new TextView(this);
            attachItem.setText("myStr");
            attachItem.setTag("myStr2");

            LinearLayout.LayoutParams llp = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
            attachItem.setLayoutParams(llp);

            ll.addView(attachItem, i++);

            // set a listener to textview
            attachItem.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    // when clicked, execute class that extends `AsyncTask`
                    new downloadAttach().
                            execute(attachItem.getTag().toString(), attachItem.getText().toString());
                }
            });
        }

And downloadAttach() downloads a file from server using http protocol. Below is code.

        HttpURLConnection con = (HttpURLConnection)(new URL("MyUrl")).openConnection();
        con.setRequestMethod("POST");
        ...
        ...
        ...
        con.setRequestProperty("Cookie", "myCookie");
        con.setDoInput(true);
        con.setDoOutput(true);

        DataOutputStream output = new DataOutputStream(con.getOutputStream());
        output.writeBytes("myQuery");
        output.close();

        InputStream is = con.getInputStream();

        FileOutputStream fos = new FileOutputStream(new File(Environment.getDataDirectory(), "fileName"));
        // In my case, getDataDirectory() returns "/data"

        byte[] buffer = new byte[1024];
        int len;

        while ((len = is.read(buffer)) > 0) {
            fos.write(buffer, 0, len);
        }

        is.close();
        fos.close();

But when I click a textview, nothing changes. There isn't a file in /data directory in my phone.

What's the problem? Someone please help.

Piyush · Accepted Answer · 2015-02-10 05:17:37Z

0

You want to download file in sd-card? if yes try changing path to

Environment.getExternalStorageDirectory() + filename

or in you app package directory use "/data/packagename/" + filename.

edited Feb 10, 2015 at 5:17

Piyush

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answered Feb 10, 2015 at 5:14

Pragati

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3 Comments

Chine Gary Over a year ago

I think you should first add log to check if the parameters transfered to downloadTask is correct and then if the downloading happened normally.

soonoo Over a year ago

@ChineGary I think parameters are transfered correctly. How can I check if the downloading happened normally? There are no exceptions at all...

Chine Gary Over a year ago

I think fos.flush() should be called before fos.close().Then you could also add some logs to record how many bytes was wrote to fos,if it's the same as the file size.

Sanketh Katta · Accepted Answer · 2015-02-10 05:43:56Z

0

You need to call #connect, otherwise the request is never made.

con.setDoInput(true);
con.setDoOutput(true);

con.connect();

DataOutputStream output = new DataOutputStream(con.getOutputStream());

answered Feb 10, 2015 at 5:43

Sanketh Katta

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1 Comment

Sanketh Katta Over a year ago

I've always used the #connect method, but it seems that calling#getOutputStream or #getInputStream implicitly invokes it.

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