我设计的应用程序通过使用价值对的邮政请求订购鸡肉食品餐厅 我显示用户ID，菜单ID，地址，longtiude，纬度，然后按下按钮下订单 按下按钮后出现错误，在后台找到异步任务 它给了我致命的异常错误 执行doInBackground（）时发生错误 它向我显示两行有错误 AddNewOrder.doInBackground（Summary.java:113） AddNewOrder.doInBackground（Summary.java:77） 引起：java.lang.NullPointerException：尝试调用虚方法＆＃39; boolean org.json.JSONObject.getBoolean（java.lang.String）＆＃39;在null对象引用上 摘要活动
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.content.SharedPreferences;
import android.os.AsyncTask;
import android.preference.PreferenceManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.List;
public class Summary extends Activity {
SharedPreferences preferences;
private ProgressDialog pDialog;
//JSONParser jsonParser = new JSONParser();
boolean errorFound;
TextView textaddress;
TextView textlongtiude;
TextView textlatitude;
TextView text2;
TextView textuser;
Button btnorder;
private static final String TAG_SUCCESS = "success";
private static final String TAG = Summary.class.getSimpleName();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_summary);
text2=(TextView)findViewById(R.id.textView3);
textaddress=(TextView)findViewById(R.id.textaddress);
textuser=(TextView)findViewById(R.id.textView4);
textlongtiude=(TextView)findViewById(R.id.textlongtiude);
textlatitude=(TextView)findViewById(R.id.textlatitude);
Intent i = getIntent();
String id = i.getStringExtra("Data4");
String address = i.getStringExtra("Data8");
String longtiude = i.getStringExtra("Data9");
String latitude = i.getStringExtra("Data10");
text2.setText(id);
textaddress.setText(address);
textlongtiude.setText(longtiude);
textlatitude.setText(latitude);
preferences= PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
String email=preferences.getString("email","");
textuser.setText(email);
pDialog = new ProgressDialog(this);
pDialog.setCancelable(false);
btnorder=(Button)findViewById(R.id.button2);
btnorder.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v)
{
addOrder(textuser.getText().toString().trim(), text2.getText().toString().trim(),
textaddress.getText().toString().trim(), textlongtiude.getText().toString().trim(),
textlatitude.getText().toString().trim());
}
});
}
//line 77
class AddNewOrder extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(Summary.this);
pDialog.setMessage("Making Order...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
protected String doInBackground(String... args) {
final JSONParser jsonParser = new JSONParser();
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("userID", args[0]));
params.add(new BasicNameValuePair("menuID", args[1]));
params.add(new BasicNameValuePair("address", args[2]));
params.add(new BasicNameValuePair("longitude", args[3]));
params.add(new BasicNameValuePair("latitude", args[4]));
JSONObject jObj = jsonParser.makeHttpRequest(AppConfig.URL_Order,
"POST", params);
try {
//Line 113
boolean error = jObj.getBoolean("error");
if (!error) {
errorFound=false;
} else {
errorFound=true;
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(String file_url) {
if (pDialog.isShowing()) {
pDialog.dismiss();
if (!errorFound){
Toast.makeText(getApplicationContext(), "User successfully registered. Try login now!", Toast.LENGTH_LONG).show();
Intent intent = new Intent(
Summary.this,
FinalResult.class);
startActivity(intent);
finish();
}
else{
Toast.makeText(getApplicationContext(), "An Error occoured!", Toast.LENGTH_LONG).show();
}
}
}
}
*/
private void addOrder(final String userID, final String menuID, final String address,
final String longitude, final String latitude) {
new AddNewOrder().execute(userID, menuID, address, longitude, latitude);
}
}
Class AppConfig
package com.pizza_final_project_app.pizza_final_project;
public class AppConfig {
public static String URL_Order = "http://xxxxxfuncti...";
json解析器
import android.util.Log;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.List;
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
// function get json from url
// by making HTTP POST or GET mehtod
public JSONObject makeHttpRequest(String url, String method,
List<NameValuePair> params) {
// Making HTTP request
try {
// check for request method
if(method == "POST"){
// request method is POST
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(params));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}else if(method == "GET"){
// request method is GET
DefaultHttpClient httpClient = new DefaultHttpClient();
String paramString = URLEncodedUtils.format(params, "utf-8");
url += "?" + paramString;
Log.d("data",url);
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
Log.d("json","data is "+json);
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}