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您好我正在构建一个登录应用程序，用户的细节将使用JSON PHP和MYSQL显示，但每当配置文件显示它崩溃我做错了什么？什么奇怪的是，这是工作前几天应用程序崩溃android开发
logcat的报告
10-05 18:55:34.088: E/AndroidRuntime(3173): FATAL EXCEPTION: main
10-05 18:55:34.088: E/AndroidRuntime(3173): java.lang.NullPointerException
10-05 18:55:34.088: E/AndroidRuntime(3173): at com.example.itmaproject.EditContactsActivity$GetProductDetails$1.run(EditContactsActivity.java:144)
10-05 18:55:34.088: E/AndroidRuntime(3173): at android.os.Handler.handleCallback(Handler.java:725)
10-05 18:55:34.088: E/AndroidRuntime(3173): at android.os.Handler.dispatchMessage(Handler.java:92)
10-05 18:55:34.088: E/AndroidRuntime(3173): at android.os.Looper.loop(Looper.java:137)
10-05 18:55:34.088: E/AndroidRuntime(3173): at android.app.ActivityThread.main(ActivityThread.java:5041)
10-05 18:55:34.088: E/AndroidRuntime(3173): at java.lang.reflect.Method.invokeNative(Native Method)
10-05 18:55:34.088: E/AndroidRuntime(3173): at java.lang.reflect.Method.invoke(Method.java:511)
10-05 18:55:34.088: E/AndroidRuntime(3173): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
10-05 18:55:34.088: E/AndroidRuntime(3173): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
10-05 18:55:34.088: E/AndroidRuntime(3173): at dalvik.system.NativeStart.main(Native Method)
我codepackage com.example.itmaproject; 公共类EditContactsActivity延伸活动{
TextView txtName;
TextView txtNumber;
TextView txtAbout;
TextView txtDate;
Button btnSave;
Button btnDelete;
TextView txtDepart;
TextView fullname;
TextView txtUser;
Button btnLogout;
String username;
SessionManager session;
// Progress Dialog
private ProgressDialog pDialog;
// JSON parser class
JSONParser jsonParser = new JSONParser();
// single product url
private static final String url_contact_details = "http://10.0.3.2/sunshine-ems/login/get_contact_details.php";
// url to update product
private static final String url_update_contact = "http://10.0.3.2/sunshine-ems/login/get_contact_details.php";
// url to delete product
private static final String url_delete_contact = "http://10.0.3.2/sunshine-ems/delete_contact.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_CONTACT = "contacts";
private static final String TAG_USERNAME = "username";
private static final String TAG_FIRSTNAME = "firstname";
private static final String TAG_DEPART = "department";
private static final String TAG_LASTNAME = "lastname";
private static final String TAG_ID = "user_id";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.edit_contact);
btnLogout = (Button) findViewById(R.id.btnLogout);
// save button
// getting product details from intent
//Intent i = getIntent();
// getting product id (pid) from intent
//pid = i.getStringExtra(TAG_USERNAME);
session = new SessionManager(getApplicationContext());
username = session.getUsername();
// Getting complete product details in background thread
new GetProductDetails().execute();
btnLogout.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// Launching All products Activity
session.logoutUser();
Intent i = new Intent(getApplicationContext(), MainActivity.class);
startActivity(i);
}
});
}
/**
* Background Async Task to Get complete product details
* */
class GetProductDetails extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(EditContactsActivity.this);
pDialog.setMessage("Loading contact details. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Getting product details in background thread
* */
protected String doInBackground(String... params) {
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
// Check for success tag
int success;
try {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("username", username));
// getting product details by making HTTP request
// Note that product details url will use GET request
JSONObject json = jsonParser.makeHttpRequest(
url_contact_details, "GET", params);
// check your log for json response
Log.d("Single Contact Details", json.toString());
// json success tag
success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// successfully received product details
JSONArray contactObj = json.getJSONArray(TAG_CONTACT); // JSON Array
// get first product object from JSON Array
JSONObject contact = contactObj.getJSONObject(0);
// product with this pid found
// Edit Text
txtName = (TextView) findViewById(R.id.inputName);
txtDepart = (TextView) findViewById(R.id.department);
//txtAbout = (TextView) findViewById(R.id.inputDesc);
txtUser = (TextView) findViewById(R.id.inputPrice);
// display product data in EditText
String fullname = contact.getString(TAG_LASTNAME)+' '+ contact.getString(TAG_FIRSTNAME);
txtName.setText(fullname);
txtDepart.setText(contact.getString(TAG_DEPART));
//txtAbout.setText(contact.getString(TAG_LASTNAME));
txtUser.setText(contact.getString(TAG_ID));
Log.v("blahhhhh", "blah hhhhblah");
}else{
// product with pid not found
Log.v("blah", "blah blah");
}
} 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 got all details
pDialog.dismiss();
}
}
/**
* Background Async Task to Save product Details
* */
class SaveProductDetails extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(EditContactsActivity.this);
pDialog.setMessage("Saving contact ...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Saving product
* */
protected String doInBackground(String... args) {
// getting updated data from EditTexts
String name = txtName.getText().toString();
//String number = txtNumber.getText().toString();
//String about = txtAbout.getText().toString();
String user = txtUser.getText().toString();
String depart = txtDepart.getText().toString();
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair(TAG_USERNAME, username));
params.add(new BasicNameValuePair(TAG_FIRSTNAME, name));
params.add(new BasicNameValuePair(TAG_DEPART, depart));
//params.add(new BasicNameValuePair(TAG_LASTNAME, about));
params.add(new BasicNameValuePair(TAG_ID, user));
// sending modified data through http request
// Notice that update product url accepts POST method
JSONObject json = jsonParser.makeHttpRequest(url_update_contact,
"POST", params);
// check json success tag
try {
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// successfully updated
Intent i = getIntent();
// send result code 100 to notify about product update
setResult(100, i);
finish();
} else {
// failed to update 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 product uupdated
pDialog.dismiss();
}
}
/*****************************************************************
* Background Async Task to Delete Product
* */
class DeleteProduct extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(EditContactsActivity.this);
pDialog.setMessage("Deleting Contact...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Deleting product
* */
protected String doInBackground(String... args) {
// Check for success tag
int success;
try {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("username", username));
// getting product details by making HTTP request
JSONObject json = jsonParser.makeHttpRequest(
url_delete_contact, "POST", params);
// check your log for json response
Log.d("Delete Contact", json.toString());
// json success tag
success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// product successfully deleted
// notify previous activity by sending code 100
Intent i = getIntent();
// send result code 100 to notify about product deletion
setResult(100, i);
finish();
}
} 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 product deleted
pDialog.dismiss();
}
}
}
线141
Log.d("Single Contact Details", json.toString());
请粘贴完整的logcat – Somu 2014-10-05 19:21:01
的解决方案是simple.Your“ json“必须为空。 – kgandroid 2014-10-05 19:42:06
好吧，显然'json'在这个阶段是'null'。看看你的服务器发送回应用程序的响应，你在这里遇到问题。或者你可能会向服务器发送错误的请求。或者由于某些内部问题，JSONParser可能会返回null。 – aga 2014-10-05 19:42:37