这是我的logcat
12-11 22:42:30.949: E/AndroidRuntime(11497): FATAL EXCEPTION: main
12-11 22:42:30.949: E/AndroidRuntime(11497): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.pmss/com.pmss.UserInfo}: java.lang.NullPointerException
12-11 22:42:30.949: E/AndroidRuntime(11497): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1573)
12-11 22:42:30.949: E/AndroidRuntime(11497): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)
12-11 22:42:30.949: E/AndroidRuntime(11497): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
12-11 22:42:30.949: E/AndroidRuntime(11497): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
12-11 22:42:30.949: E/AndroidRuntime(11497): at android.os.Handler.dispatchMessage(Handler.java:99)
12-11 22:42:30.949: E/AndroidRuntime(11497): at android.os.Looper.loop(Looper.java:130)
12-11 22:42:30.949: E/AndroidRuntime(11497): at android.app.ActivityThread.main(ActivityThread.java:3687)
12-11 22:42:30.949: E/AndroidRuntime(11497): at java.lang.reflect.Method.invokeNative(Native Method)
12-11 22:42:30.949: E/AndroidRuntime(11497): at java.lang.reflect.Method.invoke(Method.java:507)
12-11 22:42:30.949: E/AndroidRuntime(11497): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
12-11 22:42:30.949: E/AndroidRuntime(11497): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
12-11 22:42:30.949: E/AndroidRuntime(11497): at dalvik.system.NativeStart.main(Native Method)
12-11 22:42:30.949: E/AndroidRuntime(11497): Caused by: java.lang.NullPointerException
12-11 22:42:30.949: E/AndroidRuntime(11497): at android.content.ContextWrapper.getPackageName(ContextWrapper.java:120)
12-11 22:42:30.949: E/AndroidRuntime(11497): at android.preference.PreferenceManager.getDefaultSharedPreferencesName(PreferenceManager.java:353)
12-11 22:42:30.949: E/AndroidRuntime(11497): at android.preference.PreferenceManager.getDefaultSharedPreferences(PreferenceManager.java:348)
12-11 22:42:30.949: E/AndroidRuntime(11497): at com.pmss.UserInfo.<init>(UserInfo.java:37)
12-11 22:42:30.949: E/AndroidRuntime(11497): at java.lang.Class.newInstanceImpl(Native Method)
12-11 22:42:30.949: E/AndroidRuntime(11497): at java.lang.Class.newInstance(Class.java:1409)
12-11 22:42:30.949: E/AndroidRuntime(11497): at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
12-11 22:42:30.949: E/AndroidRuntime(11497): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1565)
12-11 22:42:30.949: E/AndroidRuntime(11497): ... 11 more
这是我的UserInfo.java
public class UserInfo extends ActionBarActivity implements OnClickListener {
EditText nametext, useridtext, passwordtext,
mobilenumbertext, addresstext, citytext, postcodetext, statetext;
Button update;
SharedPreferences sp = PreferenceManager
.getDefaultSharedPreferences(UserInfo.this);
String post_username = sp.getString("username", "anon");
private JSONArray mComments = null;
// Progress Dialog
private ProgressDialog pDialog;
// JSON parser class
JSONParser jsonParser = new JSONParser();
private static final String USERINFO_URL = "http://xxx.xxx.x.xx:1234/PMSS/userinfo.php";
private static final String USERINFOUPDATE_URL = "http://xxx.xxx.x.xx:1234/PMSS/userinfoupdate.php";
// ids
private static final String TAG_SUCCESS = "success";
private static final String TAG_MESSAGE = "message";
private static final String TAG_POSTS = "posts";
private static final String TAG_NAME = "name";
private static final String TAG_EMAIL = "email";
private static final String TAG_PASSWORD = "password";
private static final String TAG_MOBILENUMBER = "mobilenumber";
private static final String TAG_ADDRESS = "address";
private static final String TAG_CITY = "city";
private static final String TAG_POSTCODE = "postcode";
private static final String TAG_STATE = "state";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_user_info);
// Show the Up button in the action bar.
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
update = (Button) findViewById(R.id.update);
nametext = (EditText) findViewById(R.id.nametext);
useridtext = (EditText) findViewById(R.id.useridtext);
passwordtext = (EditText) findViewById(R.id.passwordtext);
mobilenumbertext = (EditText) findViewById(R.id.mobilenumbertext);
addresstext = (EditText) findViewById(R.id.addresstext);
citytext = (EditText) findViewById(R.id.citytext);
postcodetext = (EditText) findViewById(R.id.postcodetext);
statetext = (EditText) findViewById(R.id.statetext);
update.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
String Name = nametext.getText().toString();
String Email = useridtext.getText().toString();
String Password = passwordtext.getText().toString();
String MobileNumber = mobilenumbertext.getText().toString();
String Address = addresstext.getText().toString();
String City = citytext.getText().toString();
String PostCode = postcodetext.getText().toString();
String State = statetext.getText().toString();
new RetrieveUser().execute();
}
});
}
/**
* Set up the {@link android.app.ActionBar}, if the API is available.
*/
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
private void setupActionBar() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
getActionBar().setDisplayHomeAsUpEnabled(true);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.user_info, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
// This ID represents the Home or Up button. In the case of this
// activity, the Up button is shown. Use NavUtils to allow users
// to navigate up one level in the application structure. For
// more details, see the Navigation pattern on Android Design:
//
// http://developer.android.com/design/patterns/navigation.html#up-vs-back
//
NavUtils.navigateUpFromSameTask(this);
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
}
class RetrieveUser extends AsyncTask<Void, Void, Boolean> {
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(UserInfo.this);
pDialog.setMessage("Loading User Info...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
@Override
protected Boolean doInBackground(Void... arg0) {
updateJSONdata();
return null;
}
@Override
protected void onPostExecute(Boolean result) {
super.onPostExecute(result);
pDialog.dismiss();
nametext.setText(Name);
useridtext.setText(Email);
passwordtext.setText(Password);
mobilenumbertext.setText(MobileNumber);
addresstext.setText(Address);
citytext.setText(City);
postcodetext.setText(PostCode);
statetext.setText(State);
}
String Name, Email, Password, MobileNumber, Address, City, PostCode, State;
public void updateJSONdata() {
// ///////////////////////////////////////////////////////////////////////////////////////
// Instantiate the arraylist to contain all the JSON data.
// we are going to use a bunch of key-value pairs, referring
// to the json element name, and the content, for example,
// message it the tag, and "I'm awesome" as the content..
// Bro, it's time to power up the J parser
JSONParser jParser = new JSONParser();
// Feed the beast our comments url, and it spits us
// back a JSON object. Boo-yeah Jerome.
// JSONObject json = jParser.getJSONFromUrl(READ_COMMENTS_URL);
// Retrieving Saved Username Data:
try {
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("emailretrieve",
post_username));
Log.d("request!", "starting");
// getting product details by making HTTP request
JSONObject json = jsonParser.makeHttpRequest(USERINFO_URL,
"POST", params);
// I know I said we would check if "Posts were Avail."
// (success==1)
// before we tried to read the individual posts, but I lied...
// mComments will tell us how many "posts" or comments are
// available
mComments = json.getJSONArray(TAG_POSTS);
// looping through all posts according to the json object
// returned
for (int i = 0; i < mComments.length(); i++) {
JSONObject c = mComments.getJSONObject(i);
// gets the content of each tag
// String content = c.getString(TAG_USERID);
Name = c.getString(TAG_NAME);
Email = c.getString(TAG_EMAIL);
Password = c.getString(TAG_PASSWORD);
MobileNumber = c.getString(TAG_MOBILENUMBER);
Address = c.getString(TAG_ADDRESS);
City = c.getString(TAG_CITY);
PostCode = c.getString(TAG_POSTCODE);
State = c.getString(TAG_STATE);
}
} catch (JSONException e) {
e.printStackTrace();
}
// ////////////////////////////////////////////////////////////////////////////////
}
}
class UpdateUser extends AsyncTask<String, String, Integer> {
/**
* Before starting background thread Show Progress Dialog
* */
boolean failure = false;
String res;
int success;
String Name, Email, Password, ConfirmPassword, MobileNumber, Address,
City, PostCode, State;
public UpdateUser(String Name, String Email, String Password,
String ConfirmPassword, String MobileNumber, String Address,
String City, String PostCode, String State) {
this.Name = Name;
this.Email = Email;
this.Password = Password;
this.ConfirmPassword = ConfirmPassword;
this.MobileNumber = MobileNumber;
this.Address = Address;
this.City = City;
this.PostCode = PostCode;
this.State = State;
}
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(UserInfo.this);
pDialog.setMessage("Creating New User...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
@Override
protected Integer doInBackground(String... params) {
// TODO Auto-generated method stub
// Check for success tag
try {
// Building Parameters
List<NameValuePair> params2 = new ArrayList<NameValuePair>();
params2.add(new BasicNameValuePair("name", Name));
params2.add(new BasicNameValuePair("email", Email));
params2.add(new BasicNameValuePair("password", Password));
params2.add(new BasicNameValuePair("confirmpassword",
ConfirmPassword));
params2.add(new BasicNameValuePair("mobilenumber", MobileNumber));
params2.add(new BasicNameValuePair("address", Address));
params2.add(new BasicNameValuePair("postcode", PostCode));
params2.add(new BasicNameValuePair("city", City));
params2.add(new BasicNameValuePair("state", State));
Log.d("request!", "starting");
// Posting user data to script
JSONObject json = jsonParser.makeHttpRequest(USERINFOUPDATE_URL,
"POST", params);
// full json response
Log.d("Update attempt", json.toString());
// json success element
success = json.getInt(TAG_SUCCESS);
res = json.getString(TAG_MESSAGE);
return success;
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(Integer success) {
// dismiss the dialog once product deleted
pDialog.dismiss();
if (success != null && success == 1) {
Log.d("User Updated!", res);
Intent r = new Intent(UserInfo.this, Login.class);
startActivity(r);
finish();
Toast.makeText(
UserInfo.this,
res == null ? "Please enter the require field that marked with **"
: res, Toast.LENGTH_LONG).show();
nametext.setText(null);
useridtext.setText(null);
passwordtext.setText(null);
mobilenumbertext.setText(null);
addresstext.setText(null);
citytext.setText(null);
postcodetext.setText(null);
statetext.setText(null);
} else {
Log.d("Update Failure!", "res: " + res);
Toast.makeText(
UserInfo.this,
res == null ? "Please enter the require field that marked with **"
: res, Toast.LENGTH_LONG).show();
}
}
}
}
我想知道当我点击UserInfo界面中的MainMenu时，它只是挂在那里并强制关闭......
我的userinfo.php
<?php
require("config.inc.php");
if (!empty($_POST)) {
$query = "Select * FROM user WHERE email = :emailretrieve ";
$query_params = array(
':emailretrieve' => $_POST['emailretrieve']
);
//execute query
try {
$stmt = $db->prepare($query);
$result = $stmt->execute($query_params);
}
catch (PDOException $ex) {
$response["success"] = 0;
$response["message"] = "Database Error!";
die(json_encode($response));
}
// Finally, we can retrieve all of the found rows into an array using fetchAll
$rows = $stmt->fetchAll();
if ($rows) {
$response["success"] = 1;
$response["message"] = "Post Available!";
$response["posts"] = array();
foreach ($rows as $row) {
$post = array();
$post["name" = $row["name"];
$post["email"] = $row["email"];
$post["password"] = $row["password"];
$post["mobilenumber"] = $row["mobilenumber"];
$post["address"] = $row["address"];
$post["city"] = $row["city"];
$post["postcode"] = $row["postcode"];
$post["state"] = $row["state"];
//update our repsonse JSON data
array_push($response["posts"], $post);
}
// echoing JSON response
echo json_encode($response);
} else {
$response["success"] = 0;
$response["message"] = "No Post Available!";
die(json_encode($response));
}
}
?>
有人可以帮帮我吗？我真的不知道如何解决NullPointerException，因为我需要将EditText留空UserInfo interface以加载数据并粘贴到EditText以显示我的{{1}}数据..
答案 0 :(得分：0)
SharedPreferences sp = PreferenceManager
.getDefaultSharedPreferences(UserInfo.this);
无法从初始化程序调用上述内容。请等到onCreate()（更具体地说，直到super.onCreate()之后）才能尝试阅读SharedPreferences。