Question

我成功地可以使用AsyncTask连接到我的servlet服务器，但现在我决定我想有一个进度对话框，让用户知道正在进行网络操作。（使用2G，有时3G我可以注意到取得结果的延迟）。当AsyncTask在尝试执行此操作时崩溃时，我的问题就出现了：

private class GetQinfo extends AsyncTask<String, Void,String> {
            ProgressDialog progDailog ;
             protected void onPreExecute() {
                    super.onPreExecute();
                    progDailog= new ProgressDialog(GetTicket.this);
                    progDailog.setMessage("pls wait");
                    progDailog.setIndeterminate(false);
                    progDailog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
                    progDailog.setCancelable(true);
                    progDailog.show();
                }    
        protected String doInBackground(String... arg0) {...}
        protected void onPostExecute(String branchQ){
         ...
         progDailog.dismiss();
        }
}

但这给了我一个例外

 java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()

所以我决定停止使用AsyncTask，因为我真的不需要它（我想）。由于我不允许用户在UI上做任何事情，使用AsyncTask是否有意义？我选择了线程解决方案：

        new Thread(new Runnable() {
            public void run() {
             String line=null;
             try {
                    List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
                nameValuePairs.add(new BasicNameValuePair("command", "GetQ"));
                 nameValuePairs.add(new BasicNameValuePair("city", city));
                 nameValuePairs.add(new BasicNameValuePair("type", type));
                 nameValuePairs.add(new BasicNameValuePair("org", org));
                 nameValuePairs.add(new BasicNameValuePair("branch", spinner.getSelectedItem().toString()));
                httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs,"utf-8"));

                 // Execute HTTP Post Request
                HttpResponse response = httpclient.execute(httppost);
                HttpEntity ht = response.getEntity();
                BufferedHttpEntity buf = new BufferedHttpEntity(ht);
                InputStream is = buf.getContent();
                BufferedReader r = new BufferedReader(new InputStreamReader(is));

              line = r.readLine();
               nameValuePairs.clear();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
                line="-1";
            }

            String[] info=line.split(";");
            if(info[1].equals("-1")){
                Toast.makeText(getApplicationContext(), "Some msg", Toast.LENGTH_LONG).show();
            }
            else{
                 ....
                //Update the UI
                 }
          }
          }).start();

但由于某种原因，这引发了一个java.net.SocketException：Socket在此行上关闭 HttpResponse response = httpclient.execute（httppost）; 有任何想法吗？感谢

编辑： @Ahmad Dwaik'术士' 我从主线程调用它，我有一个微调器和一个方法

public void onItemSelected(AdapterView<?> arg0, View arg1,
             int arg2, long arg3) {
       if(arg2==0){
            //no selection
            }
        else{
new GetQinfo().execute(city,type,org,spinner.getSelectedItem().toString());
}

通过执行此操作，我得到java.lang.RuntimeException：无法在未调用Looper.prepare（）错误的线程内创建处理程序。日志是

java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
12-07 10:16:19.285: E/AndroidRuntime(1929):     at android.os.Handler.<init>(Handler.java:200)
12-07 10:16:19.285: E/AndroidRuntime(1929):     at android.os.Handler.<init>(Handler.java:114)
12-07 10:16:19.285: E/AndroidRuntime(1929):     at android.app.Dialog.<init>(Dialog.java:109)
12-07 10:16:19.285: E/AndroidRuntime(1929):     at android.app.AlertDialog.<init>(AlertDialog.java:114)
12-07 10:16:19.285: E/AndroidRuntime(1929):     at android.app.AlertDialog.<init>(AlertDialog.java:98)
12-07 10:16:19.285: E/AndroidRuntime(1929):     at android.app.ProgressDialog.<init>(ProgressDialog.java:77)
12-07 10:16:19.285: E/AndroidRuntime(1929):     at com.example.quecustomer.GetTicket$GetQinfo.onPreExecute(GetTicket.java:872)
12-07 10:16:19.285: E/AndroidRuntime(1929):     at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:587)
12-07 10:16:19.285: E/AndroidRuntime(1929):     at android.os.AsyncTask.execute(AsyncTask.java:535)
12-07 10:16:19.285: E/AndroidRuntime(1929):     at com.example.quecustomer.GetTicket$1.run(GetTicket.java:781)
12-07 10:16:19.285: E/AndroidRuntime(1929):     at java.lang.Thread.run(Thread.java:841)

GetTicket.java:872指的是这一行：

 progDailog= new ProgressDialog(GetTicket.this);

我的doInBackground： @

Override
            protected String doInBackground(String... arg0) {
                try {
                        List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
                    nameValuePairs.add(new BasicNameValuePair("command", "GetQ"));
                    nameValuePairs.add(new BasicNameValuePair("city", arg0[0]));
                    nameValuePairs.add(new BasicNameValuePair("type", arg0[1]));
                    nameValuePairs.add(new BasicNameValuePair("org", arg0[2]));
                    nameValuePairs.add(new BasicNameValuePair("branch", arg0[3]));
                    httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs,"utf-8"));
                    // Execute HTTP Post Request
                    HttpResponse response = httpclient.execute(httppost);
                    HttpEntity ht = response.getEntity();
                    BufferedHttpEntity buf = new BufferedHttpEntity(ht);
                    InputStream is = buf.getContent();
                    BufferedReader r = new BufferedReader(new InputStreamReader(is));
                   String line = r.readLine();
                   nameValuePairs.clear();
                   return line;
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                return null;
            }

编辑2 事实证明我发现了一种方法，但不确定它是否正确。它有效，所以必须是：）

我使用onProgressUpdate（Void ... none）来创建ProgressDialog并在onPostExecute（）上将其关闭。你是怎么做到的？

Answer 1

关于此错误，您没有提供太多详细信息

java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()

您似乎无法在Main＆＃34; UI＆＃34;中调用您的AsyncTask new GetQinfo().execute(args);。线程。

再次考虑使用AsyncTask，实现它并直接从主线程中调用它。如果那没有帮助显示你的完整AsyncTask子类和完整的logcat

Answer 2

您的堆栈跟踪显示您从另一个AsyncTask呼叫Thread：

12-07 10:16:19.285: E/AndroidRuntime(1929):     at com.example.quecustomer.GetTicket$1.run(GetTicket.java:781)
12-07 10:16:19.285: E/AndroidRuntime(1929):     at java.lang.Thread.run(Thread.java:841)

查看GetTicket的第781行。在那里你可能会调用new GetQinfo.execute()来带你去：

12-07 10:16:19.285: E/AndroidRuntime(1929):     at com.example.quecustomer.GetTicket$GetQinfo.onPreExecute(GetTicket.java:872)

Android中没有asyncTask的网络操作

2 个答案: