我在我的应用程序中做了一些数据库工作，我想从我的网络数据库中提取所有位置并在我的应用程序列表视图中显示它。我创建了＆＃34; API＆＃34;责任在哪里Json。
json所在的链接：http://000100023.host56.com/db_all.php
使用本教程：http://www.androidhive.info/2012/05/how-to-connect-android-with-php-mysql/
Logcat：
11-14 16:50:21.508: E/AndroidRuntime(22809): FATAL EXCEPTION: AsyncTask #1
11-14 16:50:21.508: E/AndroidRuntime(22809): Process: com.spxc.nightclubratings, PID: 22809
11-14 16:50:21.508: E/AndroidRuntime(22809): java.lang.RuntimeException: An error occured while executing doInBackground()
11-14 16:50:21.508: E/AndroidRuntime(22809): at android.os.AsyncTask$3.done(AsyncTask.java:300)
11-14 16:50:21.508: E/AndroidRuntime(22809): at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
11-14 16:50:21.508: E/AndroidRuntime(22809): at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
11-14 16:50:21.508: E/AndroidRuntime(22809): at java.util.concurrent.FutureTask.run(FutureTask.java:242)
11-14 16:50:21.508: E/AndroidRuntime(22809): at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:231)
11-14 16:50:21.508: E/AndroidRuntime(22809): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
11-14 16:50:21.508: E/AndroidRuntime(22809): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
11-14 16:50:21.508: E/AndroidRuntime(22809): at java.lang.Thread.run(Thread.java:841)
11-14 16:50:21.508: E/AndroidRuntime(22809): Caused by: java.lang.NullPointerException
11-14 16:50:21.508: E/AndroidRuntime(22809): at com.spxc.nightclubratings.SearchLocationActivity$LoadAllProducts.doInBackground(SearchLocationActivity.java:132)
11-14 16:50:21.508: E/AndroidRuntime(22809): at com.spxc.nightclubratings.SearchLocationActivity$LoadAllProducts.doInBackground(SearchLocationActivity.java:1)
11-14 16:50:21.508: E/AndroidRuntime(22809): at android.os.AsyncTask$2.call(AsyncTask.java:288)
11-14 16:50:21.508: E/AndroidRuntime(22809): at java.util.concurrent.FutureTask.run(FutureTask.java:237)
11-14 16:50:21.508: E/AndroidRuntime(22809): ... 4 more
11-14 16:50:22.199: E/WindowManager(22809): android.view.WindowLeaked: Activity com.spxc.nightclubratings.SearchLocationActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView{42313208 V.E..... R......D 0,0-729,192} that was originally added here
11-14 16:50:22.199: E/WindowManager(22809): at android.view.ViewRootImpl.<init>(ViewRootImpl.java:346)
11-14 16:50:22.199: E/WindowManager(22809): at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:248)
11-14 16:50:22.199: E/WindowManager(22809): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:69)
11-14 16:50:22.199: E/WindowManager(22809): at android.app.Dialog.show(Dialog.java:286)
11-14 16:50:22.199: E/WindowManager(22809): at com.spxc.nightclubratings.SearchLocationActivity$LoadAllProducts.onPreExecute(SearchLocationActivity.java:119)
11-14 16:50:22.199: E/WindowManager(22809): at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:587)
11-14 16:50:22.199: E/WindowManager(22809): at android.os.AsyncTask.execute(AsyncTask.java:535)
11-14 16:50:22.199: E/WindowManager(22809): at com.spxc.nightclubratings.SearchLocationActivity.onCreate(SearchLocationActivity.java:59)
11-14 16:50:22.199: E/WindowManager(22809): at android.app.Activity.performCreate(Activity.java:5243)
11-14 16:50:22.199: E/WindowManager(22809): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
11-14 16:50:22.199: E/WindowManager(22809): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2140)
11-14 16:50:22.199: E/WindowManager(22809): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2226)
11-14 16:50:22.199: E/WindowManager(22809): at android.app.ActivityThread.access$700(ActivityThread.java:135)
11-14 16:50:22.199: E/WindowManager(22809): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1397)
11-14 16:50:22.199: E/WindowManager(22809): at android.os.Handler.dispatchMessage(Handler.java:102)
**11-14 16:50:22.199: E/WindowManager(22809): at android.os.Looper.loop(Looper.java:137)
11-14 16:50:22.199: E/WindowManager(22809): at android.app.ActivityThread.main(ActivityThread.java:4998)
11-14 16:50:22.199: E/WindowManager(22809): at java.lang.reflect.Method.invokeNative(Native Method)
11-14 16:50:22.199: E/WindowManager(22809): at java.lang.reflect.Method.invoke(Method.java:515)
11-14 16:50:22.199: E/WindowManager(22809): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
11-14 16:50:22.199: E/WindowManager(22809): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
11-14 16:50:22.199: E/WindowManager(22809): at dalvik.system.NativeStart.main(Native Method)
JsonParser： 公共类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;
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;
}
}
SearchLocationAcitivity：
public class SearchLocationActivity extends ListActivity {
// Progress Dialog
private ProgressDialog pDialog;
// Creating JSON Parser object
JSONParser jParser = new JSONParser();
ArrayList<HashMap<String, String>> productsList;
// url to get all products list
private static String url_all_products = "http://http://000100023.host56.com/db_all.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_PRODUCTS = "locations";
private static final String TAG_PID = "id";
private static final String TAG_NAME = "name";
// products JSONArray
JSONArray products = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_search_location);
// Hashmap for ListView
productsList = new ArrayList<HashMap<String, String>>();
// Loading products in Background Thread
new LoadAllProducts().execute();
// Get listview
ListView lv = getListView();
// on seleting single product
// launching Edit Product Screen
lv.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
// getting values from selected ListItem
String pid = ((TextView) view.findViewById(R.id.pid)).getText()
.toString();
// Starting new intent
//Intent in = new Intent(getApplicationContext(),
// EditProductActivity.class);
// sending pid to next activity
//in.putExtra(TAG_PID, pid);
// starting new activity and expecting some response back
//startActivityForResult(in, 100);
}
});
}
// Response from Edit Product Activity
@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 Load all product by making HTTP Request
* */
class LoadAllProducts extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(SearchLocationActivity.this);
pDialog.setMessage("Loading locations. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting All products from url
* */
protected String doInBackground(String... args) {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
// getting JSON string from URL
JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);
// Check your log cat for JSON reponse
Log.d("All Products: ", json.toString());
try {
// Checking for SUCCESS TAG
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// products found
// Getting Array of Products
products = json.getJSONArray(TAG_PRODUCTS);
// looping through All Products
for (int i = 0; i < products.length(); i++) {
JSONObject c = products.getJSONObject(i);
// Storing each json item in variable
String id = c.getString(TAG_PID);
String name = c.getString(TAG_NAME);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_PID, id);
map.put(TAG_NAME, name);
// adding HashList to ArrayList
productsList.add(map);
}
} else {
// no products found
// Launch Add New product Activity
//Intent i = new Intent(getApplicationContext(),
// NewProductActivity.class);
// Closing all previous activities
//i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
//startActivity(i);
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismiss the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog after getting all products
pDialog.dismiss();
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(
SearchLocationActivity.this, productsList,
R.layout.list_item, new String[] { TAG_PID,
TAG_NAME},
new int[] { R.id.pid, R.id.name });
// updating listview
setListAdapter(adapter);
}
});
}
}
}
非常感谢任何帮助！
答案 0 :(得分：0)
您的网址字符串错误，您写道：
Private static String url_all_products = "http://http://000100023.host56.com/db_all.php";
它应该是：
Private static String url_all_products = "http://000100023.host56.com/db_all.php";
一个http://就够了;）
答案 1 :(得分：-1)
在onCreate
JSONParser jParser;
onCreate 中的
jParser = new JSONParser();