我在android中完全是绿色的。我想创建从服务器获取数据并在应用程序中显示它的App。谁能告诉我如何开始呢?我在下面尝试了这段代码。但唯一的例外就是没有找到食物。
private EditText outputStream;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
String result = null;
InputStream input = null;
StringBuilder sbuilder = null;
outputStream = (EditText)findViewById(R.id.output);
ArrayList <NameValuePair> nameValuePairs = new ArrayList <NameValuePair>();
try{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("ik.su.lt/~jbarzelis/index.php");
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response = httpclient.execute(httppost);
if (response.getStatusLine().getStatusCode() != 200) {
Log.d("MyApp", "Server encountered an error");
}
HttpEntity entity = response.getEntity();
input = entity.getContent();
}
catch(Exception e){
e.printStackTrace();
}
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(input,"iso-8859-1"),8);
sbuilder = new StringBuilder();
String line = null;
while((line = reader.readLine()) != null){
sbuilder.append(line + "\n");
}
input.close();
result = sbuilder.toString();
}
catch(Exception e){
e.printStackTrace();
}
int fd_id;
String fd_name;
try{
JSONArray jArray = new JSONArray(result);
JSONObject json_data = null;
for(int i=0;i<jArray.length();i++){
json_data = jArray.getJSONObject(i);
fd_id = json_data.getInt("FOOD_ID");
fd_name = json_data.getString("FOOD_NAME");
outputStream.append(fd_id +" " + fd_name + "\n");
}
}
catch(JSONException e1){
Toast.makeText(getBaseContext(), "No food found", Toast.LENGTH_LONG).show();
}
catch(ParseException e1){
e1.printStackTrace();
}
}
PHP代码是正确的,它显示数据。我认为上面的代码有些错误。
<?php
mysql_connect("localhost","********","**********");
mysql_select_db("test");
$sql = mysql_query("select FOOD_NAME as 'Maistas' from FOOD where FOOD_NAME like 'A%'");
while($row = mysql_fetch_assoc($sql)) $output[]=$row;
print(json_encode($output));
mysql_close;
?>
答案 0 :(得分:3)
package com.Valluru;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
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.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.ListActivity;
import android.content.Intent;
import android.net.ParseException;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
public class Food extends ListActivity {
String result = null;
InputStream is = null;
StringBuilder sb=null;
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
ListView list1;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
list1 = (ListView) findViewById(android.R.id.list);
//http post
try{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://10.0.2.2/food.php");
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,"iso-8859-1"),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
String fd_id;
String fd_name;
try{
JSONArray jArray = new JSONArray(result);
JSONObject json_data=null;
for(int i=0;i<jArray.length();i++){
json_data = jArray.getJSONObject(i);
fd_id =json_data.getString("FOOD_ID");
fd_name = json_data.getString("FOOD_NAME");
nameValuePairs.add(new list<String, String>(fd_id, fd_name));
}
list1.setAdapter(new ArrayAdapter<NameValuePair>(getApplicationContext(),android.R.layout.simple_expandable_list_item_1,nameValuePairs));
}catch(JSONException e1){
Toast.makeText(getBaseContext(), "No FOOD Found", Toast.LENGTH_LONG).show();
}catch (ParseException e1){
e1.printStackTrace();
}
}
}
list.java 包com.Valluru;
import org.apache.http.NameValuePair;
import android.R.integer;
public class list<T,V> implements NameValuePair {
T data;
V text;
public list(T data, V text)
{
this.data = data;
this.text = text;
}
@Override
public String toString(){
return text.toString();
}
@Override
public String getName() {
return (String) data;
}
@Override
public String getValue() {
return (String) text;
}
}
food.php
<?php
mysql_connect("localhost","root");
mysql_select_db("FOOD");
$sql=mysql_query("select * from FOOD where FOOD_NAME like '%'");
while($row=mysql_fetch_assoc($sql)) $output[]=$row;
print(json_encode($output));
mysql_close();
?>
答案 1 :(得分:1)
要尝试的事情:
Log
来电是否会写入LogCat
?如果是这样,它会说什么?httpclient.execute
是否有效或是否触发了异常?如果您完成上述任何步骤,则必须从项目中退后一步,先了解这些内容。在需要的地方进行实验,学习并提出具体问题。
答案 2 :(得分:1)
你解析了这些字段失败了:
fd_id = json_data.getInt("FOOD_ID");
fd_name = json_data.getString("FOOD_NAME")
这是服务器错误