执行 ASyncTask 时加载 ProgressBar
Posted
技术标签:
【中文标题】执行 ASyncTask 时加载 ProgressBar【英文标题】：Load ProgressBar while executing ASyncTask 【发布时间】：2015-09-20 13:06:50 【问题描述】：我正在完成一个应用程序，现在我想添加一个进度条或类似 Material Design 加载圈的东西。 我将在用户登录时使用它。LoginActivity 的工作原理基本上是这样的：当用户点击确定按钮时，ASyncTask 从我的 API 获取一些数据。我想要的是在 ASyncTask 对我的 API 进行查询并接收数据时显示一个进度条。 我尝试了一些库和一些教程，但没有得到任何结果。这是我的 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);
这是我的 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);
如果您需要更多详细信息，请询问。
【问题讨论】：
AsyncTask 有一个很酷的名为 publishProgress 的方法，可用于在执行时更新 UI。对于您的需求来说，这可能有点矫枉过正，但它仍然很酷。 developer.android.com/reference/android/os/… 【参考方案1】：将进度条添加到您的布局中（不确定），并在您初始化异步任务时打开可见性。在异步回调中，关闭可见性。
根据要求：
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();
结果：
@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);
【讨论】：
我在哪里增加进度条的值？在doOnBackGround()?
你会使用一个不确定的进度条，这意味着它会一直旋转直到收到回调。
更多关于ProgressBar - “在不确定模式下，进度条显示一个没有进度指示的循环动画。此模式由应用程序在任务长度未知时使用。不确定进度bar 可以是旋转的***，也可以是单杠。”
其实成功了，我实现错了，我会做更多的测试，如果我有任何问题我会告诉你..以上是关于执行 ASyncTask 时加载 ProgressBar的主要内容，如果未能解决你的问题，请参考以下文章