我似乎无法让我的android应用程序使用json将字符串变量发送到php，然后使用该变量进行查询，将返回对我的应用程序的json响应。然后我将使用结果创建一个ListView。 在显示进度对话框的部分显示之前，它不会出错 “正在加载产品详情。请稍等......”
我的java课程：
package com.example.androidhive;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.List;
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 android.util.Log;
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 method
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;
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();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
ItemName，Ingredients，Price，Category，userRating是我数据库中的列。
package com.example.androidhive;
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.annotation.TargetApi;
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.graphics.Color;
import android.os.AsyncTask;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;
public class CategoryItems extends ListActivity{
String category;
// products JSONArray
JSONArray categoryItems = null;
// Progress Dialog
private ProgressDialog pDialog;
// JSON parser class
JSONParser jsonParser = new JSONParser();
ArrayList<HashMap<String, String>> categoryItemsList;
// single product url
private static final String url_post_category_items = "http://192.168.1.2/OrderAp_php/get_category_items.php?Category=category";
private static final String url_get_category_items = "http://192.168.1.2/OrderAp_php/get_category_items.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_PRICE = "Price";
private static final String TAG_ITEMNAME = "ItemName";
private static final String TAG_INGREDIENTS = "Ingredients";
private static final String TAG_CATEGORY = "Category";
private static final String TAG_CATEGORYITEMS = "categoryItems";
@TargetApi(Build.VERSION_CODES.JELLY_BEAN)
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_category_item_menu);
Intent i = getIntent();
// getting category Name from intent
category = i.getStringExtra(TAG_CATEGORY);
new SendToPhp().execute();
// Getting categoryItems in background thread
new GetCategoryItems().execute();
// Get listview
ListView lvc = getListView();
lvc.setCacheColorHint(Color.TRANSPARENT);
// on selecting single product
// launching Edit Product Screen
lvc.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String itemName = ((TextView) view.findViewById(R.id.ci_itemName)).getText()
.toString();
String price = ((TextView) view.findViewById(R.id.ci_price)).getText()
.toString();
String ingredients = ((TextView) view.findViewById(R.id.ci_ingredients)).getText()
.toString();
String category = ((TextView) view.findViewById(R.id.ci_category)).getText()
.toString();
// Starting new intent
Intent in = new Intent(getApplicationContext(),
LiveOrderItem.class);
// sending to next activity
in.putExtra(TAG_ITEMNAME, itemName);
in.putExtra(TAG_PRICE, price);
in.putExtra(TAG_INGREDIENTS, ingredients);
in.putExtra(TAG_CATEGORY, category);
// starting new activity and expecting some response back
startActivityForResult(in, 100);
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
// if result code 100
if (resultCode == 100) {
// if result code 100 is received
// means user edited/deleted product
// reload this screen again
Intent intent = getIntent();
finish();
startActivity(intent);
}
}
/**
* Background Async Task to Get complete product details
* */
class GetCategoryItems extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(CategoryItems.this);
pDialog.setMessage("Loading product details. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Getting product 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;
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
// getting product details by making HTTP request
// Note that product details url will use GET request
JSONObject json = jsonParser.makeHttpRequest(
url_get_category_items, "GET", params);
// check your log for json response
Log.d("category items", json.toString());
try {
// json success tag
success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// products found
// Getting Array of Products
categoryItems = json.getJSONArray(TAG_CATEGORYITEMS);
for (int i = 0; i < categoryItems.length(); i++) {
JSONObject c = categoryItems.getJSONObject(i);
// Storing each json item in variable
String itemName = c.getString(TAG_ITEMNAME);
String price = c.getString(TAG_PRICE);
String ingredients = c.getString(TAG_INGREDIENTS);
String category= c.getString(TAG_CATEGORY);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
//HashMap<String, Integer> intMap = new HashMap<String, Integer>();
// adding each child node to HashMap key => value
map.put(TAG_ITEMNAME, itemName);
map.put(TAG_INGREDIENTS, ingredients);
map.put(TAG_PRICE, price);
map.put(TAG_CATEGORY, category);
// adding HashList to ArrayList
categoryItemsList.add(map);
}
}else{
// product 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();
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
CategoryItems.this,
categoryItemsList,
R.layout.category_item_list_item,
new String[] { TAG_ITEMNAME,TAG_PRICE,TAG_INGREDIENTS,TAG_CATEGORY},
new int[] { R.id.ci_itemName, R.id.ci_price,R.id.ci_ingredients, R.id.ci_category }
);
// updating listview
setListAdapter(adapter);
}
});
}
}
/**
* Background Async Task to Save product Details
* */
class SendToPhp extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(CategoryItems.this);
pDialog.setIndeterminate(false);
pDialog.setMessage("sending to php");
pDialog.setCancelable(true);
pDialog.show();
}
/**
* Saving product
* */
protected String doInBackground(String... args) {
// sending category name to php
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair(TAG_CATEGORY, category));
// sending modified data through http request
// Notice that update product url accepts POST method
JSONObject json = jsonParser.makeHttpRequest(url_post_category_items,
"POST", params);
// check json success tag
try {
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// successfully updated
Intent i = getIntent();
// send result code 100 to notify about product update
setResult(100, i);
finish();
} else {
}
} 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 product updated
pDialog.dismiss();
}
}
}
我的PHP代码：
<?php
/*
* Following code will list all the products
* A product is identified by product id (pid)
*/
// array for JSON response
$response = array();
// check for required fields
if (isset($_GET['category'])){
$category = $_GET['category'];
// include db connect class
require_once __DIR__ . '/db_connect.php';
// connecting to db
$db = new DB_CONNECT();
// get all category items from items table where category is the variable sent to php
$result = mysql_query("SELECT * FROM `items` WHERE category = '$category' LIMIT 0, 30 ") or die(mysql_error());
// check for empty result
if (mysql_num_rows($result) > 0) {
// looping through all results
// products node
$response["categoryItems"] = array();
while ($row = mysql_fetch_array($result)) {
// temp user array
$item = array();
$item["ItemName"] = $row["ItemName"];
$item["Ingredients"] = $row["Ingredients"];
$item["Price"] = $row["Price"];
$item["Picture"] = $row["Picture"];
$item["UserRating"] = $row["UserRating"];
$item["Category"] = $row["Category"];
// push single product into final response array
array_push($response["categoryItems"], $item);
}
// success
$response["success"] = 1;
// echoing JSON response
echo json_encode($response);
}else {
}
} else {
// no products found
$response["success"] = 0;
$response["message"] = "No products found";
// echo no users JSON
echo json_encode($response);
}
?>
我已多次查看代码并纠正了许多错误，但我似乎无法使其工作，我是编程的新手，这是我的高级项目
我在'makeHttpRequest'下添加了一个日志，结果如下： protected String doInBackground（String ... args）{
// sending category name to php
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair(TAG_CATEGORY, category));
// sending modified data through http request
// Notice that update product url accepts POST method
JSONObject json = jsonParser.makeHttpRequest(url_post_category_items,
"POST", params);
Log.d("category sent ", params.toString());
01-29 17:07:02.330: D/AbsListView(10360): Get MotionRecognitionManager
01-29 17:07:02.400: D/dalvikvm(10360): GC_CONCURRENT freed 1198K, 12% free 14691K/16583K, paused 13ms+14ms, total 46ms
*01-29 17:07:02.450: D/category sent(10360): [Category=Bread in oven]*
01-29 17:07:02.575: D/AndroidRuntime(10360): Shutting down VM
01-29 17:07:02.575: W/dalvikvm(10360): threadid=1: thread exiting with uncaught exception (group=0x4204b2a0)
01-29 17:07:02.585: E/AndroidRuntime(10360): FATAL EXCEPTION: main
01-29 17:07:02.585: E/AndroidRuntime(10360): android.os.NetworkOnMainThreadException
01-29 17:07:02.585: E/AndroidRuntime(10360): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1118)
01-29 17:07:02.585: E/AndroidRuntime(10360): at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
01-29 17:07:02.585: E/AndroidRuntime(10360): at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
01-29 17:07:02.585: E/AndroidRuntime(10360): at libcore.io.IoBridge.connect(IoBridge.java:112)
01-29 17:07:02.585: E/AndroidRuntime(10360): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
01-29 17:07:02.585: E/AndroidRuntime(10360): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
01-29 17:07:02.585: E/AndroidRuntime(10360): at java.net.Socket.connect(Socket.java:842)
01-29 17:07:02.585: E/AndroidRuntime(10360): at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119)
01-29 17:07:02.585: E/AndroidRuntime(10360): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:144)
01-29 17:07:02.585: E/AndroidRuntime(10360): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
01-29 17:07:02.585: E/AndroidRuntime(10360): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
01-29 17:07:02.585: E/AndroidRuntime(10360): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
01-29 17:07:02.585: E/AndroidRuntime(10360): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:670)
01-29 17:07:02.585: E/AndroidRuntime(10360): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:509)
01-29 17:07:02.585: E/AndroidRuntime(10360): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
01-29 17:07:02.585: E/AndroidRuntime(10360): at com.example.androidhive.JSONParser.makeHttpRequest(JSONParser.java:62)
01-29 17:07:02.585: E/AndroidRuntime(10360): at com.example.androidhive.CategoryItems$GetCategoryItems$1.run(CategoryItems.java:154)
01-29 17:07:02.585: E/AndroidRuntime(10360): at android.os.Handler.handleCallback(Handler.java:615)
01-29 17:07:02.585: E/AndroidRuntime(10360): at android.os.Handler.dispatchMessage(Handler.java:92)
01-29 17:07:02.585: E/AndroidRuntime(10360): at android.os.Looper.loop(Looper.java:137)
01-29 17:07:02.585: E/AndroidRuntime(10360): at android.app.ActivityThread.main(ActivityThread.java:4898)
01-29 17:07:02.585: E/AndroidRuntime(10360): at java.lang.reflect.Method.invokeNative(Native Method)
01-29 17:07:02.585: E/AndroidRuntime(10360): at java.lang.reflect.Method.invoke(Method.java:511)
01-29 17:07:02.585: E/AndroidRuntime(10360): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)
01-29 17:07:02.585: E/AndroidRuntime(10360): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)
01-29 17:07:02.585: E/AndroidRuntime(10360): at dalvik.system.NativeStart.main(Native Method)
01-29 17:12:11.110: I/Process(10360): Sending signal. PID: 10360 SIG: 9