在執行ASyncTask時加載ProgressBar

Question

我正在完成一個應用程序，現在我想添加一個進度條或類似於Material Design Loading圓圈的內容。
我要在用戶登錄時使用它。
LoginActivity的工作原理如下：當用戶點擊確定按鈕時，ASyncTask從我的API獲取一些數據。我想要的是在ASyncTask對我的API進行查詢並接收數據時顯示progressBar。
我嘗試了一些庫和一些教程，但沒有得到任何結果。
這是我LoginActivity：

package com.tumta.henrique.teste.view; 

import android.app.AlertDialog; 
import android.app.Dialog; 
import android.app.ProgressDialog; 
import android.content.DialogInterface; 
import android.content.Intent; 
import android.graphics.Color; 
import android.os.Build; 
import android.support.v7.app.ActionBar; 
import android.support.v7.app.ActionBarActivity; 
import android.os.Bundle; 
import android.view.KeyEvent; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.view.Window; 
import android.view.WindowManager; 
import android.view.inputmethod.EditorInfo; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.ProgressBar; 
import android.widget.TextView; 

import com.tumta.henrique.teste.R; 
import com.tumta.henrique.teste.model.ConsultaLogin; 
import com.tumta.henrique.teste.util.Connectivity; 

import java.util.List; 

public class LoginActivity extends ActionBarActivity implements ConsultaLogin.ConsultaConcluidaLoginListener { 

    EditText txtUsuario, txtSenha; 
    ActionBar actionbar; 
    Button btnOk, btnCancelar; 
    private AlertDialog alerta; 
    String login, senha; 
    Connectivity conn = new Connectivity(); 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     if (Build.VERSION.SDK_INT >= 21) { 
      Window window = this.getWindow(); 
      window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS); 
      window.clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS); 
      window.setStatusBarColor(this.getResources().getColor(R.color.azul_nav)); 
     } 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_login); 
     txtUsuario = (EditText) findViewById(R.id.edit_usuario); 
     txtSenha = (EditText) findViewById(R.id.edit_senha); 
     txtUsuario.setOnEditorActionListener(new TextView.OnEditorActionListener() { 
      public boolean onEditorAction(TextView v, int actionId, 
              KeyEvent event) { 
       if (actionId == EditorInfo.IME_ACTION_GO) { 
        txtSenha.requestFocus(); 
        return true; 
       } 
       return false; 
      } 
     }); 
     txtSenha.setOnEditorActionListener(new TextView.OnEditorActionListener() { 
      public boolean onEditorAction(TextView v, int actionId, 
              KeyEvent event) { 
       if (actionId == EditorInfo.IME_ACTION_GO) { 
        onClickOk(v); 
        return true; 
       } 
       return false; 
      } 
     }); 
     actionbar = getSupportActionBar(); 
     actionbar.hide(); 
     btnOk = (Button) findViewById(R.id.button_ok); 
     btnCancelar = (Button) findViewById(R.id.button_cancelar); 
     boolean isConnected = conn.isConnected(this); 
     if(isConnected == false){ 
      AlertDialog.Builder builder = new AlertDialog.Builder(this); 
      builder.setTitle("Erro"); 
      builder.setMessage(R.string.aviso_rede); 
      builder.setPositiveButton(R.string.config, new DialogInterface.OnClickListener() { 
       @Override 
       public void onClick(DialogInterface dialog, int which) { 
        startActivityForResult(new Intent(android.provider.Settings.ACTION_SETTINGS), 0); 
       } 
      }); 
      builder.setNegativeButton("Sair", new DialogInterface.OnClickListener() { 
       @Override 
       public void onClick(DialogInterface dialog, int which) { 
        finish(); 
       } 
      }); 
      alerta = builder.create(); 
      alerta.show(); 
     } 
    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.menu_login, menu); 
     return true; 
    } 

    @Override 
    public boolean onOptionsItemSelected(MenuItem item) { 
     // Handle action bar item clicks here. The action bar will 
     // automatically handle clicks on the Home/Up button, so long 
     // as you specify a parent activity in AndroidManifest.xml. 
     int id = item.getItemId(); 

     //noinspection SimplifiableIfStatement 
     if (id == R.id.action_settings) { 
      return true; 
     } 

     return super.onOptionsItemSelected(item); 
    } 

    public void onClickOk(View view) { 
     try { 
      if (txtUsuario.getText().toString().equals("") || txtSenha.getText().toString().equals("")) { 
       AlertDialog.Builder builder = new AlertDialog.Builder(this); 
       builder.setTitle("Erro"); 
       builder.setMessage("Preencha todos os campos!"); 
       builder.setNeutralButton("Ok", new DialogInterface.OnClickListener() { 
        @Override 
        public void onClick(DialogInterface dialog, int which) { 
         login = ""; 
         senha = ""; 
         txtSenha.getText().clear(); 
         txtUsuario.requestFocus(); 
        } 
       }); 
       alerta = builder.create(); 
       alerta.show(); 
      } else { 
       login = txtUsuario.getText().toString(); 
       senha = txtSenha.getText().toString(); 
       ConsultaLogin.URL_STRING = "http://186.207.85.205:7001/com.henrique.rest/api/v1/status/login?usu_login=" 
         + login + "&usu_senha=" + senha; 
       new ConsultaLogin(this).execute(); 
      } 
     } catch (Exception e) { 
      AlertDialog.Builder builder = new AlertDialog.Builder(this); 
      builder.setTitle("Erro"); 
      builder.setMessage("Ocorreu um erro inesperado! \nTente novamente."); 
      builder.setNeutralButton("Ok", new DialogInterface.OnClickListener() { 
       @Override 
       public void onClick(DialogInterface dialog, int which) { 
        login = ""; 
        senha = ""; 
        txtUsuario.getText().clear(); 
        txtSenha.getText().clear(); 
        txtUsuario.requestFocus(); 
       } 
      }); 
      alerta = builder.create(); 
      alerta.show(); 
     } 
    } 

    public void onClickCancelar(View view) { 
     finish(); 
    } 

    @Override 
    public void onConsultaConcluida(List<String> result) { 
     if (result.isEmpty()) { 
      AlertDialog.Builder builder = new AlertDialog.Builder(this); 
      builder.setTitle("Erro"); 
      builder.setMessage("Usuario ou Senha Incorreto!"); 
      builder.setNeutralButton("Ok", new DialogInterface.OnClickListener() { 
       @Override 
       public void onClick(DialogInterface dialog, int which) { 
        login = ""; 
        senha = ""; 
        txtSenha.getText().clear(); 
        txtUsuario.requestFocus(); 
       } 
      }); 
      alerta = builder.create(); 
      alerta.show(); 
     } else { 
      Intent intent = new Intent(this, MainActivity.class); 
      startActivity(intent); 
     } 
    } 
} 

，這是我的AsyncTask：

package com.tumta.henrique.teste.model; 

import android.os.AsyncTask; 
import android.util.Log; 

import org.json.JSONArray; 
import org.json.JSONException; 
import org.json.JSONObject; 

import java.io.IOException; 
import java.io.InputStream; 
import java.io.InputStreamReader; 
import java.io.Reader; 
import java.net.HttpURLConnection; 
import java.net.URL; 
import java.util.ArrayList; 
import java.util.List; 

/** 
* Created by Henrique on 16/06/2015. 
*/ 
public class ConsultaLogin extends AsyncTask<Void, Void, List<String>> { 

    private ConsultaConcluidaLoginListener listener; 

    //public static String login, senha; 
    public static String URL_STRING = ""; 


    public ConsultaLogin(ConsultaConcluidaLoginListener listener) { 
     this.listener = listener; 
    } 

    @Override 
    protected List<String> doInBackground(Void... arg0) { 
     try { 
      String resultado = ConsultaServidor(); 
      return InterpretaResultado(resultado); 
     } catch (IOException e) { 
      Log.e("Erro", "Ocorreu um erro na consulta ao servidor!", e); 
     } catch (JSONException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
     return null; 
    } 

    private List<String> InterpretaResultado(String resultado) throws JSONException { 
     JSONObject object = new JSONObject(resultado); 
     JSONArray jsonArray = object.getJSONArray("login"); 
     List<String> listaLogin = new ArrayList<>(); 
     for (int i = 0; i < jsonArray.length(); i++) { 
      JSONObject jsonLogin = jsonArray.getJSONObject(i); 
      if (jsonLogin.has("usu_nome")) { 
       String nome = jsonLogin.getString("usu_nome"); 
       listaLogin.add(i, nome); 
      } else listaLogin.clear(); 
     } 
     return listaLogin; 
    } 

    private String ConsultaServidor() throws IOException { 
     InputStream is = null; 

     try { 
      URL url = new URL(URL_STRING); 
      HttpURLConnection conn = (HttpURLConnection) url.openConnection(); 
      conn.setConnectTimeout(10000); 
      conn.setReadTimeout(15000); 
      conn.setRequestMethod("GET"); 
      conn.setDoInput(true); 
      conn.connect(); 
      conn.getResponseCode(); 

      is = conn.getInputStream(); 

      Reader reader = null; 
      reader = new InputStreamReader(is); 
      char[] buffer = new char[2048]; 
      reader.read(buffer); 
      return new String(buffer); 
     } finally { 
      if (is != null) { 
       is.close(); 
      } 
     } 
    } 

    @Override 
    protected void onPostExecute(List<String> result) { 
     super.onPostExecute(result); 

    } 

    public interface ConsultaConcluidaLoginListener { 
     void onConsultaConcluida(List<String> result); 
    } 
} 

如果您需要更多的細節，請詢問。

Answer 1

將進度條添加到佈局（不確定），並在初始化異步任務時切換可見性。在異步的回調中，關閉可見性。

根據要求：

login = txtUsuario.getText().toString(); 
senha = txtSenha.getText().toString(); 
yourProgressBar.setVisibility(View.VISIBLE); 
ConsultaLogin.URL_STRING = "http://186.207.85.205:7001/com.henrique.rest/api/v1/status/login?usu_login=" + login + "&usu_senha=" + senha; 
new ConsultaLogin(this).execute(); 

論結果：

@Override 
public void onConsultaConcluida(List<String> result) { 
    if (result.isEmpty()) { 
     AlertDialog.Builder builder = new AlertDialog.Builder(this); 
     builder.setTitle("Erro"); 
     builder.setMessage("Usuario ou Senha Incorreto!"); 
     builder.setNeutralButton("Ok", new DialogInterface.OnClickListener() { 
      @Override 
      public void onClick(DialogInterface dialog, int which) { 
       login = ""; 
       senha = ""; 
       txtSenha.getText().clear(); 
       txtUsuario.requestFocus(); 
      } 
     }); 
     alerta = builder.create(); 
     alerta.show(); 
    } else { 
     yourProgressBar.setVisibility(View.GONE); 
     Intent intent = new Intent(this, MainActivity.class); 
     startActivity(intent); 
    } 
}