搜索結果的時候，當我的應用程序嘗試顯示搜索結果的應用程序被關閉，應用程序被關閉是這樣的：http://i.imgur.com/YPl4Bfw.jpg?1安卓：顯示ListView中
這裏是logcat的信息顯示
E/Buffer Error（784）：轉換結果java.lang.NullPointerException的錯誤：lock == null
E/JSON解析器（784）：解析數據時出錯org.json.JSONException：字符0處的輸入結束
W/dalvikvm（784）：線程ID = 15：螺紋與未捕獲的異常退出（組= 0x40a71930）
E/AndroidRuntime（784）：致命異常：的AsyncTask＃4
E/AndroidRuntime（784） ：了java.lang.RuntimeException：執行doInBackground發生錯誤（）
E/AndroidRuntime（784）：在android.os.AsyncTask $ 3.done（AsyncTask.java:299）
E/AndroidRuntime（ 784）：在java.util.concurrent.FutureTask.finishCompletion（FutureTask.java:352）
E/AndroidRuntime（784）：在 java.util.concurrent.FutureTask.setException（FutureTask.java:219）
E/AndroidRuntime（784）：在 java.util.concurrent.FutureTask.run （FutureTask.java:239）
E/AndroidRuntime（784）：在android.os.AsyncTask $ SerialExecutor $ 1.run（AsyncTask.java:230）
E/AndroidRuntime（784）：在java中。 util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1080）
E/AndroidRuntime（784）：在java.util.concurrent.ThreadPoolExecutor $ Worker.run（ThreadPoolExecutor.java:573）
E/AndroidRuntime（784）：at java.lang.Thread.run（Thread.java： 856）
E/AndroidRuntime（784）：產生的原因：顯示java.lang.NullPointerException
E/AndroidRuntime（784）：在com.example.qrandrary.SearchResultDisplay $ LoadAllBooks.doInBackground（SearchResultDisplay.java:82 ）
E/AndroidRuntime（784）：at com.example.qrandrary.SearchResultDisplay $ LoadAllBooks.doInBackground（SearchResultDisplay.java:1）
E/AndroidRuntime（784）：在android.os.AsyncTask $ 2.call（AsyncTask.java:287）
E/AndroidRuntime（784）：在java.util.concurrent.FutureTask.run（FutureTask的.java：234）
E/AndroidRuntime（784）：... 4更 11-23 14：24：49.267：W/EGL_emulation（784）：eglSurfaceAttrib沒有實現
E /窗口管理（784 ）：Activity com.example.qrandrary.SearchResultDisplay泄露了窗口com.android.internal.policy.impl.PhoneWindow $ DecorView {40dec338 VE .... R ......D 0,0-470,144}這是最初添加在這裏
E/WindowManager（784）：android.view.WindowLeaked：Activity com.example.qrandrary.SearchResultDisplay已泄露窗口com.android.internal.policy.impl。 PhoneWindow $ DecorView {40dec338 VE .... R ...... D 0,0-470,144}原來在這裏添加的
E/WindowManager（784）：at android.view.ViewRootImpl。（ViewRootImpl。的java：354）
E /窗口管理（784）：在android.view.WindowManagerGlobal.addView（WindowManagerGlobal.java:216）
E /窗口管理（784）：在android.view.WindowMana gerImpl.addView（WindowManagerImpl.java:69）
E /窗口管理（784）：在android.app.Dialog.show（Dialog.java:281）
E /窗口管理（784）：在COM。 example.qrandrary.SearchResultDisplay $ LoadAllBooks.onPreExecute（SearchResultDisplay.java:68）
E /窗口管理器（784）：在android.os.AsyncTask.executeOnExecutor（AsyncTask.java:586）
E /窗口管理器（ 784）：at android.os.AsyncTask.execute（AsyncTask.java:534）
E/WindowManager（784）：at com.example.qrandrary.SearchResultDisplay.onCreate（SearchResultDisplay.java:53）
E/WindowManager（784）：at android.app.Activity.performCreate（Activity.java:5104）
E /窗口管理（784）：在android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1080）
E /窗口管理（784）：在android.app.ActivityThread.performLaunchActivity（ActivityThread.java： 2144）
E/WindowManager（784）：at android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2230）
E /窗口管理器（784）：在android.app.ActivityThread.access $ 600（ActivityThread.java:141）
E /窗口管理器（784）：在android.app.ActivityThread $ H.handleMessage（ActivityThread的.java：1234）
E /窗口管理（784）：在android.os.Handler.dispatchMessage（Handler.java:99）
E /窗口管理（784）：在android.os.Looper.loop （Looper.java:137）
E/WindowManager（784）：at ndroid.app.ActivityThread.main（A ctivityThread.java:5041）
E /窗口管理（784）：在java.lang.reflect.Method.invokeNative（本機方法）
E /窗口管理（784）：在java.lang.reflect.Method中.invoke（Method.java:511）
E /窗口管理器（784）：在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:793）
E /窗口管理器（784 ）：在com.android.internal.os.ZygoteInit.main（ZygoteInit。Java的：560）
E /窗口管理器（784）：在dalvik.system.NativeStart.main（本機方法）
這裏是代碼：
public class SearchResultDisplay extends ListActivity {
// Progress Dialog
private ProgressDialog pDialog;
// Creating JSON Parser object
JSONParser jParser = new JSONParser();
ArrayList<HashMap<String, String>> booksList;
// url to get all products list
private static String url_all_books = "http://127.0.0.1/qrandrary/quickSearch.php";
// JSON Node names
private static final String TAG_SUCCESS = "success";
private static final String TAG_BOOKS = "books";
private static final String TAG_BID = "bid";
private static final String TAG_BNAME = "bname";
private static final String TAG_AUTHORS = "authors";
private static final String TAG_STATUS = "status";
private static final String TAG_PUBLISHER = "publisher";
ListView listView;
List<RowItem> rowItems;
// products JSONArray
JSONArray books = null;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.search_resultlist_view);
rowItems = new ArrayList<RowItem>();
listView = (ListView) findViewById(android.R.id.list);
new LoadAllBooks().execute();
}
class LoadAllBooks extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(SearchResultDisplay.this);
pDialog.setMessage("Loading Books. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
protected String doInBackground(String... args) {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
// getting JSON string from URL
Bundle extras = getIntent().getExtras();
String keyword = extras.getString("keyword");
url_all_books = url_all_books + "?keyword=" + keyword;
JSONObject json = jParser.makeHttpRequest(url_all_books, "GET",
params);
// Check your log cat for JSON reponse
Log.d("All Books: ", json.toString());
try {
// Checking for SUCCESS TAG
int success = json.getInt(TAG_SUCCESS);
if (success == 1) {
// products found
// Getting Array of Products
books = json.getJSONArray(TAG_BOOKS);
// looping through All Products
for (int i = 0; i < books.length(); i++) {
JSONObject c = books.getJSONObject(i);
// Storing each json item in variable
String bid = c.getString(TAG_BID);
String bName = c.getString(TAG_BNAME);
String authors = c.getString(TAG_AUTHORS);
String publisher = c.getString(TAG_PUBLISHER);
String status = c.getString(TAG_STATUS);
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put(TAG_BID, bid);
map.put(TAG_BNAME, bName);
map.put(TAG_AUTHORS, authors);
map.put(TAG_PUBLISHER, publisher);
map.put(TAG_STATUS, status);
// adding HashList to ArrayList
booksList.add(map);
}
}
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
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
* */
BookListViewAdapter adapter = new BookListViewAdapter(SearchResultDisplay.this,R.layout.search_result_item, rowItems);
listView.setAdapter(adapter);
}
});
}
}
}
public class BookListViewAdapter extends ArrayAdapter<RowItem> {
Context context;
public BookListViewAdapter(Context context, int resourceId,
List<RowItem> items) {
super(context, resourceId, items);
this.context = context;
}
/*private view holder class*/
private class ViewHolder {
TextView txtBid;
TextView txtBname;
TextView txtAuthors;
TextView txtPublisher;
TextView txtStatus;
}
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
RowItem rowItem = getItem(position);
LayoutInflater mInflater = (LayoutInflater) context
.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
if (convertView == null) {
convertView = mInflater.inflate(R.layout.search_result_item, null);
holder = new ViewHolder();
holder.txtBid = (TextView) convertView.findViewById(R.id.bid);
holder.txtBname = (TextView) convertView.findViewById(R.id.bName);
holder.txtAuthors = (TextView) convertView.findViewById(R.id.authors);
holder.txtPublisher = (TextView) convertView.findViewById(R.id.publisher);
holder.txtStatus = (TextView) convertView.findViewById(R.id.status);
convertView.setTag(holder);
} else
holder = (ViewHolder) convertView.getTag();
holder.txtBid.setText(rowItem.getbId());
holder.txtBname.setText(rowItem.getbName());
holder.txtAuthors.setText(rowItem.getAuthors());
holder.txtPublisher.setText(rowItem.getPublisher());
holder.txtStatus.setText(rowItem.getStatus());
return convertView;
}
}
public class RowItem {
private int bId;
private String bName;
private String authors;
private String status;
private String publisher;
public RowItem(int bId, String bName, String authors, String status,
String publisher) {
this.bId = bId;
this.bName = bName;
this.authors = authors;
this.status = status;
this.publisher = publisher;
}
public int getbId() {
return bId;
}
public void setbId(int bId) {
this.bId = bId;
}
public String getbName() {
return bName;
}
public void setbName(String bName) {
this.bName = bName;
}
public String getAuthors() {
return authors;
}
public void setAuthors(String authors) {
this.authors = authors;
}
public String getStatus() {
return status;
}
public void setStatus(String status) {
this.status = status;
}
public String getPublisher() {
return publisher;
}
public void setPublisher(String publisher) {
this.publisher = publisher;
}
}
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;
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;
}
}
中有什麼問題我的應用程序？