AsyncTask，HttpClient和ProgressDialog

我正在创建一个AsyncTask来将用户登录到服务器。登录工作正常，但ProgressDialog直到进程结束才显示。只要用户点击按钮，UI就会冻结，而我的对话框不会显示出来。AsyncTask，HttpClient和ProgressDialog

我很感激任何帮助。这是我的代码。

public class MyApp extends Activity { 
    private ProgressDialog dialogo = null; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.main); 

     Button loginButton = (Button) findViewById(R.id.btnLogin); 
     loginButton.setOnClickListener(new View.OnClickListener() { 

      public void onClick(View v) { 
       SharedPreferences preferencias = PreferenceManager.getDefaultSharedPreferences(getBaseContext()); 
       String webAddress = preferencias.getString("webAddress", ""); 

       if (webAddress.isEmpty()) { 
        Toast.makeText(getBaseContext(), "Please, configure a Web Address.", Toast.LENGTH_LONG).show(); 
       } else { 
        EditText edtUsername = (EditText) findViewById(R.id.edtUsername); 
        EditText edtPassword = (EditText) findViewById(R.id.edtPassword); 

        HashMap<String, String> parametros = new HashMap<String, String>(); 
        parametros.put("username", edtUsername.getText().toString()); 
        parametros.put("password", edtPassword.getText().toString()); 

        Requisicao requisicao = new Requisicao(parametros); 
        AsyncTask<String, Void, String> resposta = requisicao.execute(webAddress + "/login"); 

        try { 
         Toast.makeText(getBaseContext(), resposta.get(), Toast.LENGTH_LONG).show(); 
        } catch (InterruptedException e) { 
         Toast.makeText(getBaseContext(), "InterruptedException (login)", Toast.LENGTH_LONG).show(); 
        } catch (ExecutionException e) { 
         Toast.makeText(getBaseContext(), "ExecutionException (login)", Toast.LENGTH_LONG).show(); 
        } 
       } 
      } 
     }); 

     ImageView engrenagem = (ImageView) findViewById(R.id.imgEngrenagem); 
     engrenagem.setOnClickListener(new View.OnClickListener() { 

      public void onClick(View v) { 
       Intent preferenciasActivity = new Intent(getBaseContext(), Preferencias.class); 
       startActivity(preferenciasActivity); 
      } 
     }); 
    } 



    public class Requisicao extends AsyncTask<String, Void, String> { 
     private final HttpClient clienteHttp = new DefaultHttpClient(); 
     private String resposta; 
     private HashMap<String, String> parametros = null; 

     public Requisicao(HashMap<String, String> params) { 
      parametros = params; 
     } 

     @Override 
     protected void onPreExecute() { 
      dialogo = new ProgressDialog(MyApp.this); 
      dialogo.setMessage("Aguarde..."); 
      dialogo.setTitle("Comunicando com o servidor"); 
      dialogo.setIndeterminate(true); 
      dialogo.setCancelable(false); 
      dialogo.show(); 
     } 

     @Override 
     protected String doInBackground(String... urls) { 
      byte[] resultado = null; 
       HttpPost post = new HttpPost(urls[0]); 
      try { 
       ArrayList<NameValuePair> paresNomeValor = new ArrayList<NameValuePair>(); 
       Iterator<String> iterator = parametros.keySet().iterator(); 
       while (iterator.hasNext()) { 
        String chave = iterator.next(); 
        paresNomeValor.add(new BasicNameValuePair(chave, parametros.get(chave))); 
       } 

       post.setEntity(new UrlEncodedFormEntity(paresNomeValor, "UTF-8")); 

       HttpResponse respostaRequisicao = clienteHttp.execute(post); 
       StatusLine statusRequisicao = respostaRequisicao.getStatusLine(); 
       if (statusRequisicao.getStatusCode() == HttpURLConnection.HTTP_OK) { 
        resultado = EntityUtils.toByteArray(respostaRequisicao.getEntity()); 
        resposta = new String(resultado, "UTF-8"); 
       } 
      } catch (UnsupportedEncodingException e) { 
      } catch (Exception e) { 
      } 
      return resposta; 
     } 

     @Override 
     protected void onPostExecute(String param) { 
      dialogo.dismiss(); 
     } 
    } 
}

来源

2012-01-27 Felsangom

尝试将按钮侦听器中的resposta.get()调用注释掉。我想它只是阻止主UI线程，直到任务完成。

来源

2012-01-27 16:14:45

@Felsangom：如果有帮助，那么只需在onPostExecute（）中移动任务结果处理即可。 – 2012-01-27 16:18:03

它的工作原理。谢谢！ – Felsangom 2012-01-27 16:23:03

为您提供了HTTPClient做到了

移动你的

private ProgressDialog dialogo = null;

到的AsyncTask的领域，因为你不似乎在任何地方使用它做，尝试在构造函数来创建你的对话框

public Requisicao(HashMap<String, String> params) { 
      parametros = params; 
      dialogo = new ProgressDialog(MyApp.this); 
     }

in postExecute

if (dialogo .isShowing()) { 
       dialogo .dismiss(); 
}

希望它有帮助。

来源

2012-01-27 16:08:03

没有。仍在冻结UI。 – Felsangom 2012-01-27 16:12:45

哪个按钮被点击？它冻结后？ – 2012-01-27 16:20:14

夫妇的事情。首先，不要为ASyncClass创建实例，因为根据android文档，您只能调用它一次。所以执行是这样的：new Requisicao().execute(webAddress + "/login");

此外，而不是调用requisicao.get()，这会，再根据文件（也称为阻塞）“为计算完成，然后获取其结果如有必要，等待”，从内部的异步类中添加替代：

protected void onProgressUpdate(Long... progress) { 
    CallBack(progress[0]); // for example 
}

如果回调是在你的UI线程的功能，这将处理处理你的进步长，或字符串，或者其他任何你想扔回去。请注意，您的ASync类必须在UI类中定义，而不是单独定义。

来源

2012-01-27 16:13:39

感谢您的提示。 – Felsangom 2012-01-27 16:23:22

AsyncTask，HttpClient和ProgressDialog

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