试图从Android应用程序填充数据库？

Question

I'm trying to populate a database table using an android app but whenever I click the submit button nothing happens. It says that the string cannot be converte into JSONObject. What may be the cause?

This is the error

12-19 02:45:16.464: E/JSON Parser(1508): Error parsing data org.json.JSONException: Value <?xml of type java.lang.String cannot be converted to JSONObject

Java code

// Edit Text
        inputName = (EditText) findViewById(R.id.inputName);
        inputPrice = (EditText) findViewById(R.id.inputPrice);
        //inputDesc = (EditText) findViewById(R.id.inputDesc);

        // Create button
        Button btnCreateProduct = (Button) findViewById(R.id.btnCreateProduct);

        // button click event
        btnCreateProduct.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {
                // creating new product in background thread
                new CreateNewProduct().execute();
            }
        });
    }

    /**
     * Background Async Task to Create new product
     * */
    class CreateNewProduct extends AsyncTask<String, String, String> {

        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(Leave.this);
            pDialog.setMessage("Creating Product..");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();
        }

        /**
         * Creating product
         * */
        protected String doInBackground(String... args) {
            String name = inputName.getText().toString();
            String price = inputPrice.getText().toString();
            //String description = inputDesc.getText().toString();

            // Building Parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair("reason", name));
            params.add(new BasicNameValuePair("price", price));
            //params.add(new BasicNameValuePair("description", description));

            // getting JSON Object
            // Note that create product url accepts POST method
            JSONObject json = jsonParser.makeHttpRequest(url_create_product,
                    "POST", params);

            // check log cat fro response
            Log.d("Create Response", json.toString());

            // check for success tag
            try {
                int success = json.getInt(TAG_SUCCESS);

                if (success == 1) {
                    // successfully created product
                    //Toast.makeText(getApplicationContext(), "Successful", Toast.LENGTH_LONG).show();
                    //Toast.makeText(getApplicationContext(), "this is my Toast message!!! =)",
                              // Toast.LENGTH_LONG).show();

                    // closing this screen

                } else {
                    // failed to create product
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }

            return null;
        }

        /**
         * After completing background task Dismiss the progress dialog
         * **/
        protected void onPostExecute(String file_url) {
            // dismiss the dialog once done
            pDialog.dismiss();
        }

    }
}

PHP

if (isset($_POST['reason'])) {

    $reason = $_POST['reason'];
    //$price = $_POST['price'];
    //$description = $_POST['description'];

    // include db connect class
    require_once __DIR__ . '/db_connect.php';

    // connecting to db
    $db = new DB_CONNECT();

    // mysql inserting a new row
    $result = mysql_query("INSERT INTO leavelist(reason) VALUES('$reason')");

    // check if row inserted or not
    if ($result) {
        // successfully inserted into database
        $response["success"] = 1;
        $response["message"] = "Product successfully created.";

        // echoing JSON response
        echo json_encode($response);
    } else {
        // failed to insert row
        $response["success"] = 0;
        $response["message"] = "Oops! An error occurred.";

        // echoing JSON response
        echo json_encode($response);
    }
} else {
    // required field is missing
    $response["success"] = 0;
    $response["message"] = "Required field(s) is missing";

    // echoing JSON response
    echo json_encode($response);

Answer 1

From the error message, it seems like the response is xml. It would be nice if you try to use the browser to see if the response is really JSON or you can try to set the return type as JSON in your PHP file as follow:

header('Content-Type: application/json');

Hope this will help.