我正在创建一个应用程序，它通过存储在localhost的Wampserver的www文件夹中的PHP脚本执行事务。
但是当我执行事务时，值没有插入到数据库中，而logcat显示此错误：
07-26 16:55:54.036: E/Buffer Error(5511): Error converting result java.lang.NullPointerException
07-26 16:55:54.037: E/JSON Parser(5511): Error parsing data org.json.JSONException: End of input at character 0 of
但我的应用程序甚至没有崩溃，并说交易成功，我的onPostExecute被称为AsyncTask。
请帮我找出导致数据库插入失败的错误。
我有两个课程JSONParser和NewProductActivity，如下所示：
这是NewProductActivity.java：
public class NewProductActivity extends Activity {
// Progress Dialog
private ProgressDialog pDialog;
JSONParser jsonParser = new JSONParser();
// url to create new product use wireless lan adapter wifi ipv4 address using ipconfig
// String url_create_product = "http://192.168.0.100/toll_system/create_product.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
String first_name;
String last_name;
String toll_no;
String toll_location;
String trans_amt;
String v_license_no;
String make_model;
String v_type;
String email_id;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.add_product);
TextView tv=(TextView)findViewById(R.id.textView1);
String contents = getIntent().getStringExtra("KEY1");
String ip_address=getIntent().getStringExtra("KEY2");
/* String arr[]=contents.split(",");
String trans_receipt_no=arr[0];
String firstname=arr[1];
String lastname=arr[2];
String toll_no=arr[3];
String toll_location=arr[4];
String trans_amt=arr[5];
String v_license_no=arr[6];
String make_model=arr[7];
String v_type=arr[8];*/
Toast toast = Toast.makeText(this, "Content:" + contents , Toast.LENGTH_LONG);
toast.show();
new CreateNewProduct().execute(contents,ip_address);
}
/**
* 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(NewProductActivity.this);
pDialog.setMessage("Woooohoooo...");
Log.d("Perform:", "Performing");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* Creating product
* */
protected String doInBackground(String... args) {
// String name = inputName.getText().toString();
// String price = inputPrice.getText().toString();
// String description = inputDesc.getText().toString();
String contents=args[0];
String ip_address=args[1];
String arr[]=contents.split(",");
Log.d("Inside doInBackground :", contents);
//String trans_receipt_no=arr[0];
first_name=arr[0];
Log.d("First_name", first_name);
last_name=arr[1];
Log.d("Last_name", last_name);
toll_no=arr[2];
toll_location=arr[3];
trans_amt=arr[4];
v_license_no=arr[5];
make_model=arr[6];
v_type=arr[7];
email_id=arr[8];
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
// params.add(new BasicNameValuePair("name", name));
//params.add(new BasicNameValuePair("price", price));
//params.add(new BasicNameValuePair("description", description));
// params.add(new BasicNameValuePair("trans_receipt_no", trans_receipt_no));
params.add(new BasicNameValuePair("first_name", first_name));
params.add(new BasicNameValuePair("last_name", last_name));
params.add(new BasicNameValuePair("toll_no", toll_no));
params.add(new BasicNameValuePair("toll_location", toll_location));
params.add(new BasicNameValuePair("trans_amount", trans_amt));
params.add(new BasicNameValuePair("v_license_no", v_license_no));
params.add(new BasicNameValuePair("v_make_model", make_model));
params.add(new BasicNameValuePair("v_type", v_type));
params.add(new BasicNameValuePair("email_id", email_id));
// getting JSON Object
String url_create_product = "http://"+ip_address+"/toll_system/create_product.php";
// 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
// Intent i = new Intent(getApplicationContext(), AllProductsActivity.class);
//startActivity(i);
String s="Transaction done!";
Toast toast = Toast.makeText(getApplicationContext(),"Status:"+s, Toast.LENGTH_LONG);
toast.show();
// closing this screen
finish();
} else {
Toast toast = Toast.makeText(getApplicationContext(),"Status:Failed", Toast.LENGTH_LONG);
toast.show();
// 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
TextView tv=(TextView)findViewById(R.id.textView1);
tv.setText("Transaction done!!!");
TextView tv1=(TextView)findViewById(R.id.textView3);
tv1.setText(first_name+" "+last_name);
TextView tv2=(TextView)findViewById(R.id.textView5);
tv2.setText(make_model);
TextView tv3=(TextView)findViewById(R.id.textView7);
tv3.setText(v_license_no);
TextView tv4=(TextView)findViewById(R.id.textView9);
tv4.setText("Rs."+trans_amt);
pDialog.dismiss();
}
}
}
这是JSONParser：
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
// function get json from url
// by making HTTP POST or GET mehtod
public JSONObject makeHttpRequest(String url, String method,
List<NameValuePair> params) {
// Making HTTP request
try {
// check for request method
if(method == "POST"){
// request method is POST
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(params));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}else if(method == "GET"){
// request method is GET
DefaultHttpClient httpClient = new DefaultHttpClient();
String paramString = URLEncodedUtils.format(params, "utf-8");
url += "?" + paramString;
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}