致命异常：主要android.os.NetworkOnMainThreadException

Question

我要上传图片，但不能运行这个，因为显示： 致命异常：主要 android.os.NetworkOnMainThreadException`public类FileUploader { 私人最终串边界; private static final String LINE_FEED =“\ r \ n”; 私人HttpURLConnection httpConn; 私人字符串字符集; private OutputStream outputStream; 私人PrintWriter作家;

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 <input type="file" name="..." /> 
* @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<String> finish() throws IOException { 
    List<String> response = new ArrayList<String>(); 

    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; 
} 

} `

请帮我:(

Answer 1

，你必须这样做在后台线程不能使用在主线程，因为它阻止网络用户界面（例如的AsyncTask）