我是Android的初学者。目前，我通过Json Parser和PHP成功检索所有数据，并在我的Android应用程序上显示数据。我的php文件中的mysql查询是：
mysql_query（“SELECT * FROM jobs）
现在，我尝试将其修改为：
mysql_query（“SELECT * FROM jobs WHERE PostName ='{$ _GET [”PostName“]}'AND Location ='{$ _GET [”Location“]}'”）
我尝试将这两个变量从Android传递给PHP，然后检索相应的数据。因此，我创建了2个editText字段供用户输入PostName和Location，然后通过editText id（iekeywordSearch，locationSearch）获取其值。修改代码并运行后，会出现2个错误。任何人都可以帮助解决问题吗？提前谢谢！
logcat的
06-16 16:49:50.950 21893-21946/com.example.chongcng2.jobsearch W/dalvikvm﹕ threadid=10: thread exiting with uncaught exception (group=0xa62fd288)
06-16 16:49:50.950 21893-21946/com.example.chongcng2.jobsearch E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:299)
at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:856)
Caused by: java.lang.NullPointerException
at com.example.chongcng2.jobsearch.JsonParsing.MainActivityJsonParsing$GetContacts. doInBackground(MainActivityJsonParsing.java:144)
at com.example.chongcng2.jobsearch.JsonParsing.MainActivityJsonParsing$GetContacts. doInBackground(MainActivityJsonParsing.java:128)
at android.os.AsyncTask$2.call(AsyncTask.java:287)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
at java.util.concurrent.FutureTask.run(FutureTask.java:137)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
at java.lang.Thread.run(Thread.java:856)
======================================================================
06-16 16:55:17.846 24544-24544/com.example.chongcng2.jobsearch E/WindowManager﹕ Activity com.example.chongcng2.jobsearch.JsonParsing.MainActivityJsonParsing has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@536ade08 that was originally added here
android.view.WindowLeaked: Activity com.example.chongcng2.jobsearch.JsonParsing.MainActivityJsonParsing has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@536ade08 that was originally added here
at android.view.ViewRootImpl.<init>(ViewRootImpl.java:374)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:292)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:224)
at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:149)
at android.view.Window$LocalWindowManager.addView(Window.java:547)
at android.app.Dialog.show(Dialog.java:277)
at com.example.chongcng2.jobsearch.JsonParsing.MainActivityJsonParsing$GetContacts.onPreExecute(MainActivityJsonParsing.java:137)
at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:586)
at android.os.AsyncTask.execute(AsyncTask.java:534)
at com.example.chongcng2.jobsearch.JsonParsing.MainActivityJsonParsing.onCreate(MainActivityJsonParsing.java:122)
at android.app.Activity.performCreate(Activity.java:5008)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
at android.app.ActivityThread.access$600(ActivityThread.java:130)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
get_json.php
<?php
$host = "localhost";
$user = "root";
$pw = "123456";
$database_name = "mydatabase";
$con = @mysql_connect($host, $user, $pw) or die("Cannot connect Database");
mysql_select_db($database_name) or die("Cannot select Database.");
$result = mysql_query("SELECT * FROM jobs WHERE PostName = '{$_GET["PostName"]}' AND Location = '{$_GET["Location"]}'") or die(mysql_error());
// check for empty result
if (mysql_num_rows($result) > 0) {
// looping through all results
$response["info"] = array();
while ($row = mysql_fetch_array($result)) {
// temp user array
$info= array();
$info["PostName"] = $row["PostName"];
$info["Location"] = $row["Location"];
$info["Salary"] = $row["Salary"];
$info["Responsibility"] = $row["Responsibility"];
$info["Company"] = $row["Company"];
$info["Contact"] = $row["Contact"];
// push single idiom array into final response array
array_push($response["info"], $info);
}
// success
$response["success"] = 1;
// echoing JSON response
echo json_encode($response);
} else {
// no products found
$response["success"] = 0;
$response["message"] = "No info found";
// echo no users JSON
echo json_encode($response);
}
?>
MainActivityJsonParsing.java
public class MainActivityJsonParsing extends ListActivity {
EditText inputPostName;
EditText inputLocation;
List<NameValuePair> params = new ArrayList<NameValuePair>();
private ProgressDialog pDialog;
// URL to get contacts JSON
private static String url = "http://192.168.0.102/get_json.php";
// JSON Node names
private static final String TAG_INFO = "info";
private static final String TAG_POSTNAME = "PostName";
private static final String TAG_LOCATION = "Location";
private static final String TAG_SALARY = "Salary";
private static final String TAG_RESPONSIBILITY = "Responsibility";
private static final String TAG_COMPANY = "Company";
private static final String TAG_CONTACT = "Contact";
// contacts JSONArray
JSONArray infos = null;
// Hashmap for ListView
ArrayList<HashMap<String, String>> infoList;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_json_parsing);
// Edit Text
inputPostName = (EditText) findViewById(R.id.keywordSearch);
inputLocation = (EditText) findViewById(R.id.locationSearch);
infoList = new ArrayList<HashMap<String, String>>();
final ListView lv = getListView();
// Listview on item click listener
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String name = ((TextView) view.findViewById(R.id.PostName))
.getText().toString();
String cost = ((TextView) view.findViewById(R.id.Location))
.getText().toString();
String description = ((TextView) view.findViewById(R.id.Salary))
.getText().toString();
HashMap<String, String> info = new HashMap<String, String>();
info=(HashMap<String, String>)lv.getAdapter().getItem(position);
// Starting single contact activity
Intent in = new Intent(getApplicationContext(),
SingleJobActivity.class);
in.putExtra(TAG_POSTNAME, name);
in.putExtra(TAG_LOCATION, cost);
in.putExtra(TAG_SALARY, description);
in.putExtra(TAG_RESPONSIBILITY, info.get(TAG_RESPONSIBILITY));
in.putExtra(TAG_COMPANY, info.get(TAG_COMPANY));
in.putExtra(TAG_CONTACT, info.get(TAG_CONTACT));
startActivity(in);
}
});
// Calling async task to get json
new GetContacts().execute();
}
/**
* Async task class to get json by making HTTP call
* */
private class GetContacts extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(MainActivityJsonParsing.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
String postname = inputPostName.getText().toString();
String location = inputLocation.getText().toString();
params.add(new BasicNameValuePair("PostName", postname));
params.add(new BasicNameValuePair("Location", location));
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
// Creating service handler class instance
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET, params);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
infos = jsonObj.getJSONArray(TAG_INFO);
// looping through All Contacts
for (int i = 0; i < infos.length(); i++) {
JSONObject c = infos.getJSONObject(i);
String id = c.getString(TAG_POSTNAME);
String name = c.getString(TAG_LOCATION);
String email = c.getString(TAG_SALARY);
String address = c.getString(TAG_RESPONSIBILITY);
String gender = c.getString(TAG_COMPANY);
String mobile = c.getString(TAG_CONTACT);
// tmp hashmap for single contact
HashMap<String, String> info = new HashMap<String, String>();
// adding each child node to HashMap key => value
info.put(TAG_POSTNAME, id);
info.put(TAG_LOCATION, name);
info.put(TAG_SALARY, email);
info.put(TAG_RESPONSIBILITY, address);
info.put(TAG_COMPANY, gender);
info.put(TAG_CONTACT, mobile);
// adding contact to contact list
infoList.add(info);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
MainActivityJsonParsing.this, infoList,
R.layout.list_item_json_parsing, new String[] { TAG_POSTNAME, TAG_LOCATION,
TAG_SALARY }, new int[] { R.id.PostName,
R.id.Location, R.id.Salary });
setListAdapter(adapter);
}
}
}
ServiceHandler.java（处理POST / GET）
public class ServiceHandler {
static String response = null;
public final static int GET = 1;
public final static int POST = 2;
public ServiceHandler() {
}
/**
* Making service call
* @url - url to make request
* @method - http request method
* */
public String makeServiceCall(String url, int method) {
return this.makeServiceCall(url, method, null);
}
/**
* Making service call
* @url - url to make request
* @method - http request method
* @params - http request params
* */
public String makeServiceCall(String url, int method,
List<NameValuePair> params) {
try {
// http client
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpEntity httpEntity = null;
HttpResponse httpResponse = null;
// Checking http request method type
if (method == POST) {
HttpPost httpPost = new HttpPost(url);
// adding post params
if (params != null) {
httpPost.setEntity(new UrlEncodedFormEntity(params));
}
httpResponse = httpClient.execute(httpPost);
} else if (method == GET) {
// appending params to url
if (params != null) {
String paramString = URLEncodedUtils
.format(params, "utf-8");
url += "?" + paramString;
}
HttpGet httpGet = new HttpGet(url);
httpResponse = httpClient.execute(httpGet);
}
httpEntity = httpResponse.getEntity();
response = EntityUtils.toString(httpEntity);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return response;
}
}
MainActivityJsonParsing.java [已编辑]
public class MainActivityJsonParsing extends ListActivity {
EditText inputPostName;
EditText inputLocation;
List<NameValuePair> params = new ArrayList<NameValuePair>();
private ProgressDialog pDialog;
private static String url = "http://192.168.0.102/get_json.php";
// JSON Node names
private static final String TAG_INFO = "info";
private static final String TAG_POSTNAME = "PostName";
private static final String TAG_LOCATION = "Location";
private static final String TAG_SALARY = "Salary";
private static final String TAG_RESPONSIBILITY = "Responsibility";
private static final String TAG_COMPANY = "Company";
private static final String TAG_CONTACT = "Contact";
// contacts JSONArray
JSONArray infos = null;
// Hashmap for ListView
ArrayList<HashMap<String, String>> infoList;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_json_parsing);
// Edit Text
inputPostName = (EditText) findViewById(R.id.keywordSearch);
inputLocation = (EditText) findViewById(R.id.locationSearch);
infoList = new ArrayList<HashMap<String, String>>();
final ListView lv = getListView();
// Listview on item click listener
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String name = ((TextView) view.findViewById(R.id.PostName))
.getText().toString();
String cost = ((TextView) view.findViewById(R.id.Location))
.getText().toString();
String description = ((TextView) view.findViewById(R.id.Salary))
.getText().toString();
HashMap<String, String> info = new HashMap<String, String>();
info=(HashMap<String, String>)lv.getAdapter().getItem(position);
Intent in = new Intent(getApplicationContext(),
SingleJobActivity.class);
in.putExtra(TAG_POSTNAME, name);
in.putExtra(TAG_LOCATION, cost);
in.putExtra(TAG_SALARY, description);
in.putExtra(TAG_RESPONSIBILITY, info.get(TAG_RESPONSIBILITY));
in.putExtra(TAG_COMPANY, info.get(TAG_COMPANY));
in.putExtra(TAG_CONTACT, info.get(TAG_CONTACT));
startActivity(in);
}
});
// Calling async task to get json
new GetContacts().execute();
}
private class GetContacts extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(MainActivityJsonParsing.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
String postname = inputPostName.getText().toString();
String location = inputLocation.getText().toString();
params.add(new BasicNameValuePair("PostName", postname));
params.add(new BasicNameValuePair("Location", location));
}
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
ServiceHandler sh = new ServiceHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET, params);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
infos = jsonObj.getJSONArray(TAG_INFO);
// looping through All Contacts
for (int i = 0; i < infos.length(); i++) {
JSONObject c = infos.getJSONObject(i);
String id = c.getString(TAG_POSTNAME);
String name = c.getString(TAG_LOCATION);
String email = c.getString(TAG_SALARY);
String address = c.getString(TAG_RESPONSIBILITY);
String gender = c.getString(TAG_COMPANY);
String mobile = c.getString(TAG_CONTACT);
// tmp hashmap for single contact
HashMap<String, String> info = new HashMap<String, String>();
// adding each child node to HashMap key => value
info.put(TAG_POSTNAME, id);
info.put(TAG_LOCATION, name);
info.put(TAG_SALARY, email);
info.put(TAG_RESPONSIBILITY, address);
info.put(TAG_COMPANY, gender);
info.put(TAG_CONTACT, mobile);
// adding contact to contact list
infoList.add(info);
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
ListAdapter adapter = new SimpleAdapter(
MainActivityJsonParsing.this, infoList,
R.layout.list_item_json_parsing, new String[] { TAG_POSTNAME, TAG_LOCATION,
TAG_SALARY }, new int[] { R.id.PostName,
R.id.Location, R.id.Salary });
setListAdapter(adapter);
}
}
}
logcat 2
06-17 17:41:46.585 4121-4121/com.example.chongcng2.jobsearch E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.chongcng2.jobsearch/com.example.chongcng2.jobsearch.JsonParsing.MainActivityJsonParsing}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
at android.app.ActivityThread.access$600(ActivityThread.java:130)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4745)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.example.chongcng2.jobsearch.JsonParsing.MainActivityJsonParsing$GetContacts.onPreExecute(MainActivityJsonParsing.java:139)
at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:586)
at android.os.AsyncTask.execute(AsyncTask.java:534)
at com.example.chongcng2.jobsearch.JsonParsing.MainActivityJsonParsing.onCreate(MainActivityJsonParsing.java:122)
at android.app.Activity.performCreate(Activity.java:5008)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2084）
at android.app.ActivityThread.access$600(ActivityThread.java:130)
在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1195）
在android.os.Handler.dispatchMessage（Handler.java:99）
在android.os.Looper.loop（Looper.java:137）
在android.app.ActivityThread.main（ActivityThread.java:4745）
at java.lang.reflect.Method.invokeNative（Native Method）
at java.lang.reflect.Method.invoke（Method.java:511）
at com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:786）
at com.android.internal.os.ZygoteInit.main（ZygoteInit.java:553）
at dalvik.system.NativeStart.main（Native Method）
MainActivity.java
public class MainActivity extends ActionBarActivity {
Button button;
Button button_jsonParsing;
Button button_jobCreation;
private EditText keywordSearch;
private EditText locationSearch;
private Button jobSearchButton;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
addListenerOnButton();
addListenerOnButton_jsonParsing();
addListenerOnButton_jobCreation();
//link to UI
keywordSearch=(EditText)findViewById(R.id.keywordSearch);
locationSearch=(EditText)findViewById(R.id.locationSearch);
jobSearchButton=(Button)findViewById(R.id.jobSearchButton);
//jobSearchButton.setOnClickListener(this);
}
public void addListenerOnButton() {
final Context context = this;
button = (Button) findViewById(R.id.button2);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
Intent intent = new Intent(context, MainActivityFavourite.class);
startActivity(intent);
}
});
}
public void addListenerOnButton_jsonParsing() {
final Context context = this;
button_jsonParsing = (Button) findViewById(R.id.jobSearchButton);
button_jsonParsing.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
Intent intent = new Intent(context, MainActivityJsonParsing.class);
startActivity(intent);
}
});
}
public void addListenerOnButton_jobCreation() {
final Context context = this;
button_jobCreation = (Button) findViewById(R.id.jobCreationButton);
button_jobCreation.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
Intent intent = new Intent(context, MainScreenActivity.class);
startActivity(intent);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main_screen, menu);
return true;
}
}
答案 0 :(得分：0)
在执行onPostExecute中获取参数的操作时，您似乎实际在doInBackground中执行数据库查询。
这会导致我猜的泄漏窗口。
doInBackground在与主UI线程不同的线程中执行。您不能修改除创建它之外的其他线程内的任何视图。
尝试使用您的代码获取onPreExecute中的参数，doInBackground中的实际网络操作以及onPostExecute.中的结果处理