Android 后台异步任务中Boolean.Org.Json.Jsonobject Do方法中的空指针异常_Android

Android 后台异步任务中Boolean.Org.Json.Jsonobject Do方法中的空指针异常

android

Android 后台异步任务中Boolean.Org.Json.Jsonobject Do方法中的空指针异常,android,Android,我设计了一个应用程序，通过使用值对的post请求为鸡肉食品餐厅下订单我显示用户id、菜单id、地址、龙图德、纬度，然后按按钮下订单按下按钮并在后台异步任务中找到后显示错误它给了我致命的异常错误执行doInBackground（）时出错它告诉我两行有错误 AddNewOrder.doInBackground（Summary.java:113） AddNewOrder.doInBackground（Summary.java:77）原因：java.lang.NullPointerExcep

我设计了一个应用程序，通过使用值对的post请求为鸡肉食品餐厅下订单我显示用户id、菜单id、地址、龙图德、纬度，然后按按钮下订单按下按钮并在后台异步任务中找到后显示错误它给了我致命的异常错误执行doInBackground（）时出错它告诉我两行有错误 AddNewOrder.doInBackground（Summary.java:113） AddNewOrder.doInBackground（Summary.java:77）原因：java.lang.NullPointerException:尝试对空对象引用调用虚拟方法“boolean org.json.JSONObject.getBoolean（java.lang.String）” 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);

}

}

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;

}
}

导入android.util.Log；
导入org.apache.http.HttpEntity；
导入org.apache.http.HttpResponse；
导入org.apache.http.NameValuePair；
导入org.apache.http.client.ClientProtocolException；
导入org.apache.http.client.entity.UrlEncodedFormEntity；
导入org.apache.http.client.methods.HttpGet；
导入org.apache.http.client.methods.HttpPost；
导入org.apache.http.client.utils.URLEncodedUtils；
导入org.apache.http.impl.client.DefaultHttpClient；
导入org.json.JSONException；
导入org.json.JSONObject；
导入java.io.BufferedReader；
导入java.io.IOException；
导入java.io.InputStream；
导入java.io.InputStreamReader；
导入java.io.UnsupportedEncodingException；
导入java.util.List；
公共类JSONParser{
静态InputStream为空；
静态JSONObject jObj=null；
静态字符串json=“”；
//建造师
公共JSONParser（）{
}
//函数从url获取json
//通过使用HTTP POST或GET方法
公共JSONObject makeHttpRequest（字符串url、字符串方法、，
列表参数）{
//发出HTTP请求
试一试{
//检查请求方法
如果（方法==“POST”）{
//请求方法为POST
//defaultHttpClient
DefaultHttpClient httpClient=新的DefaultHttpClient（）；
HttpPost HttpPost=新的HttpPost（url）；
setEntity（新的UrlEncodedFormEntity（参数））；
HttpResponse HttpResponse=httpClient.execute（httpPost）；
HttpEntity HttpEntity=httpResponse.getEntity（）；
is=httpEntity.getContent（）；
}else if（方法==“GET”）{
//请求方法是GET
DefaultHttpClient httpClient=新的DefaultHttpClient（）；
String paramString=URLEncodedUtils.format（params，“utf-8”）；
url+=“？”+参数字符串；
Log.d（“数据”，url）；
HttpGet HttpGet=新的HttpGet（url）；
HttpResponse HttpResponse=httpClient.execute（httpGet）；
HttpEntity HttpEntity=httpResponse.getEntity（）；
is=httpEntity.getContent（）；
} 
}捕获（不支持的编码异常e）{
e、 printStackTrace（）；
}捕获（客户端协议例外e）{
e、 printStackTrace（）；
}捕获（IOE异常）{
e、 printStackTrace（）；
}
试一试{
BufferedReader reader=新的BufferedReader（新的InputStreamReader(
is，“iso-8859-1”），8）；
StringBuilder sb=新的StringBuilder（）；
字符串行=null；
而（（line=reader.readLine（））！=null）{
sb.追加（第+行“\n”）；
}
is.close（）；
json=sb.toString（）；
Log.d（“json”，“数据是”+json）；
}捕获（例外e）{
Log.e（“缓冲区错误”，“错误转换结果”+e.toString（））；
}
试一试{
jObj=新的JSONObject（json）；
}捕获（JSONException e）{
Log.e（“JSON解析器”，“错误解析数据”+e.toString（））；
}
//返回JSON字符串
返回jObj；
}
}

很明显，

jObj

在第113行是空的。这可能是因为没有从http请求中获得有效的JSON响应。请参见此处了解更多信息：另外，请注意，此版本的JSONParser类使用了不推荐的（后来删除的）api调用，有关JSONParser类的更新版本，请参见此处：我在此处的链接中使用源代码：stackoverflow.com/questions/3303660/，解析数据org.json.JSONException时会出现错误：我解决问题的方法的输入字符0处结束听起来好像没有得到有效的json。要解决此问题，请找出服务器未向您提供有效JSON响应的原因。

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;

}
}