现在解决了崩溃问题后，应用程序没有执行更新或删除 当我更新它立即崩溃，但当我删除它显示我吐司，然后没有任何反应
这是班级
public class EditCard extends Activity {
EditText txtName;
EditText txtPosition;
EditText txtCollege;
EditText txtPhone;
Button btnSave;
Button btnDelete;
String cid;
// Progress Dialog
private ProgressDialog pDialog;
// JSON parser class
JSONParser jsonParser = new JSONParser();
// single product url
private static final String url_card_details = "http://XXX";
// url to update product
private static final String url_update_card = "http://XXX";
// url to delete product
private static final String url_delete_card = "http://XXX";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_CARDS = "cards";
private static final String TAG_CID = "cid";
private static final String TAG_CNAME = "name";
private static final String TAG_POSITION = "position";
private static final String TAG_COLLEGE = "college";
private static final String TAG_PHONE = "phone";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.edit_card);
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
.permitAll().build();
StrictMode.setThreadPolicy(policy);
// save button
btnSave = (Button) findViewById(R.id.SaveCard);
btnDelete = (Button) findViewById(R.id.DeleteCard);
// getting product details from intent
Intent i = getIntent();
// getting product id (pid) from intent
cid = i.getStringExtra(TAG_CID);
// Getting complete product details in background thread
new GetCardDetails().execute();
// save button click event
btnSave.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// starting background task to update product
new SaveCardDetails().execute();
}
});
// Delete button click event
btnDelete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
// deleting product in background thread
new DeleteCard().execute();
}
});
}
/**
* Background Async Task to Get complete product details
* */
class GetCardDetails extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(EditCard.this);
pDialog.setMessage("Loading card 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("cid", cid));
// getting product details by making HTTP request
// Note that product details url will use GET request
JSONObject json = jsonParser.makeHttpRequest(
url_card_details, "GET", params);
// check your log for json response
Log.d("Single Product Details", json.toString());
// json success tag
success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// successfully received product details
JSONArray cardObj = json
.getJSONArray(TAG_CARDS); // JSON Array
// get first product object from JSON Array
JSONObject card = cardObj.getJSONObject(0);
// product with this pid found
// Edit Text
txtName = (EditText) findViewById(R.id.editCard1);
txtPosition = (EditText) findViewById(R.id.editCard2);
txtCollege= (EditText) findViewById(R.id.editCard3);
txtPhone= (EditText) findViewById(R.id.editCard4);
// display product data in EditText
txtName.setText(card.getString(TAG_CNAME));
txtPosition.setText(card.getString(TAG_POSITION));
txtCollege.setText(card.getString(TAG_COLLEGE));
txtPhone.setText(card.getString(TAG_PHONE));
}else{
// product with pid not found
}
} 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 SaveCardDetails extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(EditCard.this);
pDialog.setMessage("Saving Card ...");
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 position = txtPosition.getText().toString();
String college = txtCollege.getText().toString();
String phone = txtPhone.getText().toString();
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("name", name));
params.add(new BasicNameValuePair("position", position));
params.add(new BasicNameValuePair("college", college));
params.add(new BasicNameValuePair("phone", phone));
// sending modified data through http request
// Notice that update product url accepts POST method
JSONObject json = jsonParser.makeHttpRequest(url_update_card,
"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
Toast.makeText(getApplicationContext(), "The Student Card Updated sucessfully", Toast.LENGTH_LONG).show();
pDialog.dismiss();
}
}
/*****************************************************************
* Background Async Task to Delete Product
* */
class DeleteCard extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(EditCard.this);
pDialog.setMessage("Deleting Card...");
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("cid", cid));
// getting product details by making HTTP request
JSONObject json = jsonParser.makeHttpRequest(
url_delete_card, "POST", params);
// check your log for json response
Log.d("Delete Card", 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
Toast.makeText(getApplicationContext(), "The Student Card deleted sucessfully", Toast.LENGTH_LONG).show();
pDialog.dismiss();
}
}
}
这是我更新时的LogCat
07-18 01:15:53.053: W/dalvikvm(8740): threadid=11: thread exiting with uncaught exception (group=0x40a71930)
07-18 01:15:53.383: E/AndroidRuntime(8740): FATAL EXCEPTION: AsyncTask #1
07-18 01:15:53.383: E/AndroidRuntime(8740): java.lang.RuntimeException: An error occured while executing doInBackground()
07-18 01:15:53.383: E/AndroidRuntime(8740): at android.os.AsyncTask$3.done(AsyncTask.java:299)
07-18 01:15:53.383: E/AndroidRuntime(8740): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
07-18 01:15:53.383: E/AndroidRuntime(8740): at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
07-18 01:15:53.383: E/AndroidRuntime(8740): at java.util.concurrent.FutureTask.run(FutureTask.java:239)
07-18 01:15:53.383: E/AndroidRuntime(8740): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
07-18 01:15:53.383: E/AndroidRuntime(8740): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
07-18 01:15:53.383: E/AndroidRuntime(8740): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
07-18 01:15:53.383: E/AndroidRuntime(8740): at java.lang.Thread.run(Thread.java:856)
07-18 01:15:53.383: E/AndroidRuntime(8740): Caused by: java.lang.NullPointerException
07-18 01:15:53.383: E/AndroidRuntime(8740): at com.example.ahliaevents.EditCard$SaveCardDetails.doInBackground(EditCard.java:210)
07-18 01:15:53.383: E/AndroidRuntime(8740): at com.example.ahliaevents.EditCard$SaveCardDetails.doInBackground(EditCard.java:1)
07-18 01:15:53.383: E/AndroidRuntime(8740): at android.os.AsyncTask$2.call(AsyncTask.java:287)
07-18 01:15:53.383: E/AndroidRuntime(8740): at java.util.concurrent.FutureTask.run(FutureTask.java:234)
07-18 01:15:53.383: E/AndroidRuntime(8740): ... 4 more
这是我删除时的LogCat
07-18 01:18:01.584: E/JSON Parser(8850): Error parsing data org.json.JSONException: Value <!DOCTYPE of type java.lang.String cannot be converted to JSONObject
答案 0 :(得分：0)
对于您的删除崩溃，您没有从服务器返回JSON，您可能会收到错误页面。解析器期望看到JSON，它看到的似乎是XML / XHTML文档的开头。
对于你的其他崩溃，只需在第210行查看你的来源。你得到一个NullPointerException，这意味着你期望某个东西成为一个对象，但它是一个空引用。
最令人担忧的是你在runOnUiThread()内使用doInBackground() doInBackground的全部意义是避免UI线程。