我是安卓新手。那么我在下面的代码中试图做的是发送一个http请求到一个php文件,json从那里得到响应。在 php 文件中,我试图显示从 A 开始的城市名称。每当我运行代码时,我都会收到此错误:“"org.json.jsonexception value doctype of type java.lang.string cannot be converted to jsonarray
。所有相关线程都没有帮助,或者我无法理解那里给出的解决方案。这是我的 Java 代码MainActivity.java
package com.list;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.net.ParseException;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
JSONArray jArray;
String result = null;
InputStream is = null;
StringBuilder sb=null;
int ct_id;
String ct_name;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView textview1 = (TextView)findViewById(R.id.textView1);
textview1.setText("Erqem");
ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
//http post
try{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://10.0.2.2/city.php");
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
}catch(Exception e){
Log.e("log_tag", "Error in http connection"+e.toString());
}
//convert response to string
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"UTF-8"),8);
sb = new StringBuilder();
sb.append(reader.readLine() + "\n");
String line="0";
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result=sb.toString();
}catch(Exception e){
Log.e("log_tag", "Error converting result "+e.toString());
}
//paring data
try{
jArray = new JSONArray(result);
JSONObject json_data = new JSONObject();
json_data=null;
for(int i=0;i<jArray.length();i++){
json_data = jArray.getJSONObject(i);
ct_id=json_data.getInt("CITY_ID");
ct_name=json_data.getString("CITY_NAME");
textview1.setText(ct_name);
}
}
catch(JSONException e1){
Toast.makeText(getBaseContext(), "No City Found"+e1.toString() ,Toast.LENGTH_LONG).show();
Log.e("log_tag", "Error converting result "+e1.getMessage() );
} catch (ParseException e1) {
e1.printStackTrace();
}
}
}
.php 文件
<?php
header('Content-type=application/json; charset=utf-8');
mysql_connect("","root","");
mysql_select_db("Deal");
$sql=mysql_query("select * from CITY where CITY_NAME like 'A%'");
while($row=mysql_fetch_assoc($sql))
$output[]=$row;
print(json_encode($output));
mysql_close();
?>
任何帮助将不胜感激。谢谢。