当我尝试转到另一个页面时，我的应用程序崩溃了，这是错误代码;
01-05 18:49:25.976: E/AndroidRuntime(7596): FATAL EXCEPTION: main
01-05 18:49:25.976: E/AndroidRuntime(7596): android.os.NetworkOnMainThreadException
01-05 18:49:25.976: E/AndroidRuntime(7596): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1144)
01-05 18:49:25.976: E/AndroidRuntime(7596): at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
01-05 18:49:25.976: E/AndroidRuntime(7596): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
01-05 18:49:25.976: E/AndroidRuntime(7596): at java.net.InetAddress.getAllByName(InetAddress.java:214)
01-05 18:49:25.976: E/AndroidRuntime(7596): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
01-05 18:49:25.976: E/AndroidRuntime(7596): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
01-05 18:49:25.976: E/AndroidRuntime(7596): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
01-05 18:49:25.976: E/AndroidRuntime(7596): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
01-05 18:49:25.976: E/AndroidRuntime(7596): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:670)
01-05 18:49:25.976: E/AndroidRuntime(7596): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:509)
01-05 18:49:25.976: E/AndroidRuntime(7596): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
01-05 18:49:25.976: E/AndroidRuntime(7596): at com.example.splashscreentwo.JSONParser.makeHttpRequest(JSONParser.java:62)
01-05 18:49:25.976: E/AndroidRuntime(7596): at com.example.splashscreentwo.EmployeePayslip$GetEmployeeDetails$1.run(EmployeePayslip.java:127)
01-05 18:49:25.976: E/AndroidRuntime(7596): at android.os.Handler.handleCallback(Handler.java:730)
01-05 18:49:25.976: E/AndroidRuntime(7596): at android.os.Handler.dispatchMessage(Handler.java:92)
01-05 18:49:25.976: E/AndroidRuntime(7596): at android.os.Looper.loop(Looper.java:137)
01-05 18:49:25.976: E/AndroidRuntime(7596): at android.app.ActivityThread.main(ActivityThread.java:5493)
01-05 18:49:25.976: E/AndroidRuntime(7596): at java.lang.reflect.Method.invokeNative(Native Method)
01-05 18:49:25.976: E/AndroidRuntime(7596): at java.lang.reflect.Method.invoke(Method.java:525)
01-05 18:49:25.976: E/AndroidRuntime(7596): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1209)
01-05 18:49:25.976: E/AndroidRuntime(7596): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1025)
01-05 18:49:25.976: E/AndroidRuntime(7596): at dalvik.system.NativeStart.main(Native Method)
我不太了解代码，也不确定是什么导致了问题，以下是我的 java 类。
package com.example.splashscreentwo;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.net.Uri;
import android.os.AsyncTask;
import android.os.Bundle;
import android.telephony.SmsManager;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageButton;
import android.widget.TextView;
import android.widget.Toast;
public class EmployeePayslip extends Activity {
private ProgressDialog pDialog;
String pid;
TextView employeeName;
TextView Desc;
TextView txtCreatedAt;
// Creating JSON Parser object
JSONParser jParser = new JSONParser();
JSONArray payslip = null;
ArrayList<HashMap<String, String>> payslipList;
// url to get all fulltime employees list
private static String url_payslip = "http://rollit.sg/FYP/ExportPayslip.php";
private static final String url_employees_details = "http://rollit.sg/FYP/get_employees_details.php";
private static final String TAG_SUCCESS = "success";
private static final String TAG_PAYSLIP = "payslip";
private static final String TAG_PID = "pid";
private static final String TAG_NAME = "name";
private static final String TAG_PAYSLIPNO = "payslipno";
private static final String TAG_NETSALARY = "netsalary";
private static final String TAG_ISSUEDATE = "issuedate";
private static final String TAG_STARTOFPAYSLIP = "startofpayslip";
private static final String TAG_ENDOFPAYSLIP = "endofpayslip";
private static final String TAG_TYPEOFALLOWANCE = "typeofallowance";
private static final String TAG_ALLOWANCEAMT = "allowanceamt";
private static final String TAG_ALLOWANCEDATE = "allowancedate";
private static final String TAG_AVAILABLEALLOWANCE = "availableallowance";
private static final String TAG_TYPEOFDEDUCTION = "typeofdeduction";
private static final String TAG_DEDUCTIONAMT = "deductionamt";
private static final String TAG_DEDUCTIONDATE = "deductiondate";
private static final String TAG_AGREEDOVERTIMERATE = "agreedovertimerate";
private static final String TAG_OVERTIMERATE = "overtimerate";
private static final String TAG_STARTOFOVERTIMEPERIOD = "startofovertimeperiod";
private static final String TAG_ENDOFOVERTIMEPERIOD = "endofovertimeperiod";
private static final String TAG_BASICSALARY = "basicsalary";
private static final String TAG_EXTRAPAYMENT = "extrapayment";
private static final String TAG_EMPLOYEE = "employ";
private static final String TAG_SALARY = "pay";
private static final String TAG_DESCRIPTION = "description";
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.employeepayslip);
payslipList = new ArrayList<HashMap<String, String>>();
// Loading all fulltime employees in Background Thread
// getting employee details from intent
Intent i = getIntent();
// getting employee id (pid) from intent
pid = i.getStringExtra(TAG_PID);
new GetEmployeeDetails().execute();
}
class GetEmployeeDetails extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(EmployeePayslip.this);
pDialog.setMessage("Loading employees details. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Getting employee 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("pid", pid));
// getting employee details by making HTTP request
// Note that employee details url will use GET request
JSONObject json = jParser.makeHttpRequest(
url_employees_details, "GET", params);
// check your log for json response
Log.d("Employee Details", json.toString());
// json success tag
success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// successfully received employee details
JSONArray employeeObj = json
.getJSONArray(TAG_EMPLOYEE); // JSON Array
// get first employee object from JSON Array
JSONObject employee = employeeObj.getJSONObject(0);
// employee with this pid found
// Edit Text
employeeName = (TextView) findViewById(R.id.employeeName);
Desc = (TextView) findViewById(R.id.department);
// display employee data in EditText
employeeName.setText(employee.getString(TAG_NAME));
Desc.setText(employee.getString(TAG_DESCRIPTION));
}else{
// employee 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();
}
}
}
那么，是什么导致了这个问题呢？任何帮助都非常感谢，谢谢！
删除
runOnUiThread(new Runnable() {
public void run() {
http://developer.android.com/reference/android/app/Activity.html#runOnUiThread（java.lang.Runnable）
您不需要在后台线程上调用此 coz doInbackground。如果需要更新 UI，可以在 UI 线程上调用的onPostExecute中执行此操作。
http://developer.android.com/reference/android/os/NetworkOnMainThreadException.html
在onCreate中初始化
employeeName = (TextView) findViewById(R.id.employeeName);
Desc = (TextView) findViewById(R.id.department);
您还应该将employeeName.setText(employee.getString(TAG_NAME))和Desc.setText(employee.getString(TAG_DESCRIPTION))移动到onPostExecute 。
后台计算的结果以 doInbackground 格式返回，参数化为 onPostExecute 。所以根据结果返回的更新 UI 相应地onPostExecute
阅读 4 个步骤 @
http://developer.android.com/reference/android/os/AsyncTask.html