Android httpPost avec des paramètres et des fichiers

Vous devez utiliser un multipart http post, comme dans les formulaires HTML. Cela peut être fait avec une bibliothèque.
Voir le post Envoi d'images à l'aide de Http Post pour un exemple complet.

Cela fonctionne comme un charme pour moi:

public int uploadFile(String sourceFileUri) {  
String fileName=sourceFileUri;
HttpURLConnection conn = null;
DataOutputStream dos = null;  
String lineEnd = "\r\n";
String twoHyphens = "--";
String boundary = "------hellojosh";
int bytesRead, bytesAvailable, bufferSize;
byte[] buffer;
int maxBufferSize = 1 * 1024 * 1024; 
File sourceFile = new File(fileName); 
Log.e("joshtag", "Uploading: sourcefileURI, "+fileName);
if (!sourceFile.isFile()) {                                
Log.e("uploadFile", "Source File not exist :"+appSingleton.getInstance().photouri);//FullPath);                
runOnUiThread(new Runnable() {
public void run() {             
//messageText.setText("Source File not exist :"
}
});          
return 0;  //RETURN #1
}
else{
try{                
FileInputStream fileInputStream = new FileInputStream(sourceFile);           
URL url = new URL(upLoadServerUri);
Log.v("joshtag",url.toString());
//Open a HTTP  connection to  the URL
conn = (HttpURLConnection) url.openConnection(); 
conn.setDoInput(true); //Allow Inputs
conn.setDoOutput(true); //Allow Outputs
conn.setUseCaches(false); //Don't use a Cached Copy            s       
conn.setRequestMethod("POST");                     
conn.setRequestProperty("Connection", "Keep-Alive");
conn.setRequestProperty("ENCTYPE", "multipart/form-data");
conn.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);     
conn.setRequestProperty("file", fileName);                     
conn.setRequestProperty("user", user_id));
dos = new DataOutputStream(conn.getOutputStream());  
//ADD Some -F Form parameters, helping method
//... is declared down below
addFormField(dos, "someParameter", "someValue");
dos.writeBytes(twoHyphens + boundary + lineEnd); 
dos.writeBytes("Content-Disposition: form-data; name=\"file\";filename=\"" + fileName + "\"" + lineEnd);                    
dos.writeBytes(lineEnd);      
//create a buffer of  maximum size
bytesAvailable = fileInputStream.available();           
bufferSize = Math.min(bytesAvailable, maxBufferSize);
buffer = new byte[bufferSize];         
//read file and write it into form...
bytesRead = fileInputStream.read(buffer, 0, bufferSize);   
while (bytesRead > 0) {                        
dos.write(buffer, 0, bufferSize);
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
Log.i("joshtag","->");
}
//send multipart form data necesssary after file data...
dos.writeBytes(lineEnd);
dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
//Responses from the server (code and message)
serverResponseCode = conn.getResponseCode();
String serverResponseMessage = conn.getResponseMessage().toString();              
Log.i("joshtag", "HTTP Response is : "  + serverResponseMessage + ": " + serverResponseCode);  
//------------------ read the SERVER RESPONSE
DataInputStream inStream;
try {
inStream = new DataInputStream(conn.getInputStream());
String str;
while ((str = inStream.readLine()) != null) {
Log.e("joshtag", "SOF Server Response" + str);
}
inStream.close();
}
catch (IOException ioex) {
Log.e("joshtag", "SOF error: " + ioex.getMessage(), ioex);
}
//close the streams //
fileInputStream.close();
dos.flush();
dos.close();    
if(serverResponseCode == 200){ 
//Do something                       
}//END IF Response code 200  
dialog.dismiss();
}//END TRY - FILE READ      
catch (MalformedURLException ex) {
ex.printStackTrace();     
Log.e("joshtag", "UL error: " + ex.getMessage(), ex);  
} //CATCH - URL Exception
catch (Exception e) {           
e.printStackTrace();             
Log.e("Upload file to server Exception", "Exception : "+ e.getMessage(), e);
} //
return serverResponseCode; //after try       
}//END ELSE, if file exists.
}
public static String lineEnd = "\r\n";
public static String twoHyphens = "--";
public static String boundary = "------------------------afb19f4aeefb356c";
public static void addFormField(DataOutputStream dos, String parameter, String value){
try {
dos.writeBytes(twoHyphens + boundary + lineEnd);
dos.writeBytes("Content-Disposition: form-data; name=\""+parameter+"\"" + lineEnd);
dos.writeBytes(lineEnd);
dos.writeBytes(value);
dos.writeBytes(lineEnd);
}
catch(Exception e){
}
}

Mise à JOUR: Si vous avez besoin d'envoyer des paramètres avec le fichier,
utilisation:

conn.setRequestProperty("someParameter","someValue")
//or
addFormField(DataOutputStream dos, String parameter, String value)

...comme indiqué dans le code ci-dessus. L'un ou l'autre devrait fonctionner, si le serveur que vous essayez de vous connecter n'est pas complètement connus pour vous.