我正在尝试从扩展AsyncTask的类中为post方法发送一些参数，但这不起作用，因为我收到错误。
这是我的logcat
06-30 20:59:14.159 614-632/com.example.aastudillo.cats
E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:278)
at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:856)
Caused by: java.lang.NullPointerException
at com.example.aastudillo.cats.Login$ValidatingLogin.doInBackground(Login.java:110)
at com.example.aastudillo.cats.Login$ValidatingLogin.doInBackground(Login.java:93)
at android.os.AsyncTask$2.call(AsyncTask.java:264)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:856)
login.java
public class Login extends Activity {
public static final String url = "http://192.168.0.217:80/Services/WebService.php";
private static final String TAG_SUCCESS = "success";
private static final String TAG_MESSAGE = "message";
private ProgressDialog pDialog;
Button btnLogin;
Button btnLinkToRegister;
EditText emailEditText;
EditText PasswordEditText;
TextView Vista;
HttpHandler httpHandler = new HttpHandler();
@Override
public void onPause() {
super.onPause();
if (pDialog != null) {
pDialog.dismiss();
}
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
Vista = (TextView) findViewById(R.id.Vista);
emailEditText = (EditText) findViewById(R.id.email);
PasswordEditText = (EditText) findViewById(R.id.password);
btnLogin = (Button) findViewById(R.id.btnLogin);
btnLinkToRegister = (Button) findViewById(R.id.btnLinkToRegisterScreen);
btnLogin.setOnClickListener(new Button.OnClickListener() {
@Override
public void onClick(View v) {
btnLogin.setClickable(false);
new ValidatingLogin().execute();
}
});
btnLinkToRegister.setOnClickListener(new Button.OnClickListener() {
@Override
public void onClick(View v) {
Intent i = new Intent(Login.this, RegisterActivity.class);
startActivity(i);
}
});
}
@Override
public boolean onCreateOptionsMenu (Menu menu){
getMenuInflater().inflate(R.menu.menu_login, menu);
return true;
}
public class ValidatingLogin extends AsyncTask<String, String, String> {
int success;
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(Login.this);
pDialog.setMessage("Espere...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
protected String doInBackground(String... params) {
String SendPersonal = emailEditText.getText().toString();
String SendPassword = PasswordEditText.getText().toString();
try {
List<NameValuePair> Params = new ArrayList <NameValuePair>();
Params.add(new BasicNameValuePair("Cod_Personal", SendPersonal));
Params.add(new BasicNameValuePair("Password", SendPassword));
JSONObject J = httpHandler.makeHttpRequest(url,"POST", Params);
success = J.getInt(TAG_SUCCESS);
if (success == 1) {
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(Login.this);
SharedPreferences.Editor edit = prefs.edit();
edit.putString("Cod_Personal", SendPassword);
edit.commit();
Intent i = new Intent(Login.this, activity_actividad_principal.class);
finish();
startActivity(i);
return J.getString(TAG_MESSAGE);
} else {
return J.getString(TAG_MESSAGE);
}
} catch (JSONException e) {
}
return null;
}
protected void onPostExecute(String file_url) {
pDialog.dismiss();
if (file_url != null) {
Toast.makeText(getApplicationContext(), file_url, Toast.LENGTH_LONG).show();
} else {
}
}
}
}
httphandler.java
public class HttpHandler{
static InputStream is = null;
static JSONObject Jobj = null;
static String json="";
//Constructor
public HttpHandler(){
}
public JSONObject getJSONFromUrl(final String url){
try{
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try{
String line = null;
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
StringBuilder sb = new StringBuilder();
while((line = reader.readLine())!=null){
sb.append(line+"\n");
}
is.close();
json= sb.toString();
}catch (Exception e){
Log.e("TAG",""+ e.toString());
}
try{
Jobj = new JSONObject(json);
}catch (JSONException e){
Log.e("JSON Parser","Error Parsing Data" +e.toString());
}
return Jobj;
}
public JSONObject makeHttpRequest(String url,String method,List<NameValuePair> Params ){
try{
if (method == "POST"){
HttpClient 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"){
HttpClient 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;
}
}
答案 0 :(得分：0)
你的HttpHandler返回null，导致NPE。它返回null的原因应该是之前的日志，但是你省略了它。
此外，我看到你试图从禁止的后台线程开始或完成一个活动。