FATAL EXCEPTION: main android.os.NetworkOnMainThreadException : <p>i want upload images but cant run this because show:
FATAL EXCEPTION: main
    android.os.NetworkOnMainThreadException`public class FileUploader {
    private final String boundary;
    private static final String LINE_FEED = "\r\n";
    private HttpURLConnection httpConn;
    private String charset;
    private OutputStream outputStream;
    private PrintWriter writer;</p>

<pre><code>public FileUploader(String requestURL, String charset)
        throws IOException {
    this.charset = charset;

        // creates a unique boundary based on time stamp
        boundary = "===" + System.currentTimeMillis() + "===";

        URL url = new URL(requestURL);
        httpConn = (HttpURLConnection) url.openConnection();
        httpConn.setUseCaches(false);
        httpConn.setDoOutput(true); // indicates POST method
        httpConn.setDoInput(true);
        httpConn.setRequestProperty("Content-Type",
                "multipart/form-data; boundary=" + boundary);
        httpConn.setRequestProperty("User-Agent", "CodeJava Agent");
        httpConn.setRequestProperty("Test", "Bonjour");
        outputStream = httpConn.getOutputStream();
        writer = new PrintWriter(new OutputStreamWriter(outputStream, charset),
                true);


}

/**
 * Adds a form field to the request
 * @param name field name
 * @param value field value
 */
public void addFormField(String name, String value) {
    writer.append("--" + boundary).append(LINE_FEED);
    writer.append("Content-Disposition: form-data; name=\"" + name + "\"")
            .append(LINE_FEED);
    writer.append("Content-Type: text/plain; charset=" + charset).append(
            LINE_FEED);
    writer.append(LINE_FEED);
    writer.append(value).append(LINE_FEED);
    writer.flush();
}

/**
 * Adds a upload file section to the request
 * @param fieldName name attribute in &lt;input type="file" name="..." /&gt;
 * @param uploadFile a File to be uploaded
 * @throws IOException
 */
public void addFilePart(String fieldName, File uploadFile)
        throws IOException {
    String fileName = uploadFile.getName();
    writer.append("--" + boundary).append(LINE_FEED);
    writer.append(
            "Content-Disposition: form-data; name=\"" + fieldName
                    + "\"; filename=\"" + fileName + "\"")
            .append(LINE_FEED);
    writer.append(
            "Content-Type: "
                    + URLConnection.guessContentTypeFromName(fileName))
            .append(LINE_FEED);
    writer.append("Content-Transfer-Encoding: binary").append(LINE_FEED);
    writer.append(LINE_FEED);
    writer.flush();

    FileInputStream inputStream = new FileInputStream(uploadFile);
    byte[] buffer = new byte[4096];
    int bytesRead = -1;
    while ((bytesRead = inputStream.read(buffer)) != -1) {
        outputStream.write(buffer, 0, bytesRead);
    }
    outputStream.flush();
    inputStream.close();

    writer.append(LINE_FEED);
    writer.flush();
}

/**
 * Adds a header field to the request.
 * @param name - name of the header field
 * @param value - value of the header field
 */
public void addHeaderField(String name, String value) {
    writer.append(name + ": " + value).append(LINE_FEED);
    writer.flush();
}

/**
 * Completes the request and receives response from the server.
 * @return a list of Strings as response in case the server returned
 * status OK, otherwise an exception is thrown.
 * @throws IOException
 */
public List&lt;String&gt; finish() throws IOException {
    List&lt;String&gt; response = new ArrayList&lt;String&gt;();

    writer.append(LINE_FEED).flush();
    writer.append("--" + boundary + "--").append(LINE_FEED);
    writer.close();

    // checks server's status code first
    int status = httpConn.getResponseCode();
    if (status == HttpURLConnection.HTTP_OK) {
        BufferedReader reader = new BufferedReader(new InputStreamReader(
                httpConn.getInputStream()));
        String line = null;
        while ((line = reader.readLine()) != null) {
            response.add(line);
        }
        reader.close();
        httpConn.disconnect();
    } else {
        throw new IOException("Server returned non-OK status: " + status);
    }

    return response;
}
</code></pre>

<p>}
`</p>

<p>please help me :(</p>
