Async DoInBackground Listview에서 충돌이 발생했습니다.

Question

동료의 stackflower 코드가 생겨서 어떤 이유로 응용 프로그램이 비정상적으로 작동하고 Async에 익숙하지 않아 많은 디버깅 경험이 없습니다. HttPost를 통해 데이터를 다운로드하고 간단한 목록보기로 데이터를 나열하려고합니다.

이

코드 :

public class ChatService extends ListActivity { 
    /** Called when the activity is first created. */ 

    BufferedReader in = null; 
    String data = null; 
    List headlines; 
    List links; 
    String GotPass; 
    ArrayAdapter adapter; 
    String GotUname; 
    public static final String PREFS_NAME ="MyPregs"; 
    private GetTask getTask; 
    public ListView fList; 

    @Override 
    public void onCreate(Bundle savedInstanceState) 
    { 
     super.onCreate(savedInstanceState); 
     getTask = new GetTask(); 
     getTask.execute(); 

     ArrayAdapter adapter = new ArrayAdapter(this, 
       android.R.layout.simple_list_item_1, headlines); 
    } 

    public class GetTask extends AsyncTask<Void, Void, List> 
    { 
     @Override 
     protected List doInBackground(Void... params) { 
     return load(); 
     }  

     @Override 
     protected void onPostExecute(List result) { 


     fList.setAdapter(adapter); 
     } 
    } 

    private List load() { 
     // get your data from http 
     // add to your list, probably you can use model. 
     BufferedReader in = null; 
     String data = null; 
     Bundle gotData = getIntent().getExtras(); 
     if(gotData != null) 
     { 
      GotPass = gotData.getString("key!"); 
      GotUname = gotData.getString("key!!"); 
     } 
     SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0); 
     String username = settings.getString("key1", null); 
     String password = settings.getString("key2", null); 
     if(username.equals("irock97")) { 
      Toast.makeText(getApplicationContext(), "yaya", Toast.LENGTH_SHORT).show(); 
     } else { 
      Toast.makeText(getApplicationContext(), "fail", Toast.LENGTH_SHORT).show(); 
     } 

     HttpClient httpclient = new DefaultHttpClient(); 

     /* login.php returns true if username and password is equal to saranga */ 
     HttpPost httppost = new HttpPost("http://gta5news.com/login.php"); 

     try { 
      // Add user name and password 
      List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2); 
      nameValuePairs.add(new BasicNameValuePair("username", username)); 
      nameValuePairs.add(new BasicNameValuePair("password", password)); 
      httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs)); 

      // Execute HTTP Post Request 
      Log.w("HttpPost", "Execute HTTP Post Request"); 
      HttpResponse response = httpclient.execute(httppost); 
      in = new BufferedReader(new InputStreamReader(response.getEntity() 
        .getContent())); 
      StringBuffer sb = new StringBuffer(""); 
      String l =""; 
      String nl =""; 
      while ((l =in.readLine()) !=null) { 
       sb.append(l + nl); 
      } 
      in.close(); 
      data = sb.toString(); 

      ListView lv = getListView(); 
      lv.setTextFilterEnabled(true); 

      headlines.add(data); 




      ArrayAdapter adapter = new ArrayAdapter(this, 
        android.R.layout.simple_list_item_1, headlines); 

      setListAdapter(adapter); 


     } catch (ClientProtocolException e) { 
      e.printStackTrace(); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
     return headlines; 
    } 

    private StringBuilder inputStreamToString1(InputStream is) { 
     String line = ""; 
     StringBuilder total = new StringBuilder(); 
     // Wrap a BufferedReader around the InputStream 
     BufferedReader rd = new BufferedReader(new InputStreamReader(is)); 
     // Read response until the end 
     try { 
      while ((line = rd.readLine()) != null) { 
       total.append(line); 
      } 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
     // Return full string 
     return total; 
    } 




    } 

로그 캣 : doInbackground에서

04-10 20:47:18.526: E/AndroidRuntime(574): FATAL EXCEPTION: AsyncTask #1 
04-10 20:47:18.526: E/AndroidRuntime(574): java.lang.RuntimeException: An error occured while executing doInBackground() 
04-10 20:47:18.526: E/AndroidRuntime(574): at android.os.AsyncTask$3.done(AsyncTask.java:200) 
04-10 20:47:18.526: E/AndroidRuntime(574): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273) 
04-10 20:47:18.526: E/AndroidRuntime(574): at java.util.concurrent.FutureTask.setException(FutureTask.java:124) 
04-10 20:47:18.526: E/AndroidRuntime(574): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307) 
04-10 20:47:18.526: E/AndroidRuntime(574): at java.util.concurrent.FutureTask.run(FutureTask.java:137) 
04-10 20:47:18.526: E/AndroidRuntime(574): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1068) 
04-10 20:47:18.526: E/AndroidRuntime(574): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:561) 
04-10 20:47:18.526: E/AndroidRuntime(574): at java.lang.Thread.run(Thread.java:1096) 
04-10 20:47:18.526: E/AndroidRuntime(574): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare() 
04-10 20:47:18.526: E/AndroidRuntime(574): at android.os.Handler.<init>(Handler.java:121) 
04-10 20:47:18.526: E/AndroidRuntime(574): at android.widget.Toast.<init>(Toast.java:68) 
04-10 20:47:18.526: E/AndroidRuntime(574): at android.widget.Toast.makeText(Toast.java:231) 
04-10 20:47:18.526: E/AndroidRuntime(574): at com.gta5news.bananaphone.ChatService.load(ChatService.java:97) 
04-10 20:47:18.526: E/AndroidRuntime(574): at com.gta5news.bananaphone.ChatService.access$0(ChatService.java:82) 
04-10 20:47:18.526: E/AndroidRuntime(574): at com.gta5news.bananaphone.ChatService$GetTask.doInBackground(ChatService.java:71) 
04-10 20:47:18.526: E/AndroidRuntime(574): at com.gta5news.bananaphone.ChatService$GetTask.doInBackground(ChatService.java:1) 
04-10 20:47:18.526: E/AndroidRuntime(574): at android.os.AsyncTask$2.call(AsyncTask.java:185) 
04-10 20:47:18.526: E/AndroidRuntime(574): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305) 

Answer 1

You are calling Toast in load() function which is in DoInBackground. 
Toast messages touches UI thread which you can't do that. 

This line makes it crash. 
Toast.makeText(getApplicationContext(), "yaya", Toast.LENGTH_SHORT).show(); 

Change you load function signature: 
This is your function: 
private List load() { 

don't return a list, create a modal container and return it like: 
private ReturnModel load() { 

and create a modal like this, and set and get this modal: 
and in your load function,fill this returnmodal, set passworderror true or false instead of toast message, and onpostexecute function, check password error and do your toast message there. 




package com.nesim.test; 

import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.util.ArrayList; 
import java.util.List; 

import org.apache.http.HttpResponse; 
import org.apache.http.NameValuePair; 
import org.apache.http.client.ClientProtocolException; 
import org.apache.http.client.HttpClient; 
import org.apache.http.client.entity.UrlEncodedFormEntity; 
import org.apache.http.client.methods.HttpPost; 
import org.apache.http.impl.client.DefaultHttpClient; 
import org.apache.http.message.BasicNameValuePair; 

import android.app.ListActivity; 
import android.content.SharedPreferences; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.util.Log; 
import android.widget.ArrayAdapter; 
import android.widget.ListView; 
import android.widget.Toast; 

public class ChatService extends ListActivity { 
    String GotPass; 
    String GotUname; 
    public static final String PREFS_NAME = "MyPregs"; 
    private GetTask getTask; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    getTask = new GetTask(); 
    getTask.execute(); 
    } 

    public class GetTask extends AsyncTask<Void, Void, ReturnModel> { 
    @Override 
    protected ReturnModel doInBackground(Void... params) { 
     return load(); 
    } 

    @Override 
    protected void onPostExecute(ReturnModel result) { 

     if(result.passworderror == true) 
     { 
     Toast.makeText(getApplicationContext(), "fail", Toast.LENGTH_SHORT).show(); 
     } 
     else 
     { 
     Toast.makeText(getApplicationContext(), "yaya", Toast.LENGTH_SHORT).show(); 

     ListView lv = getListView(); 
     lv.setTextFilterEnabled(true); 

     ArrayAdapter<String> adapter = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1, result.getheadlines()); 
     setListAdapter(adapter); 
     } 
    } 
    } 

    private ReturnModel load() { 
    ReturnModel returnModel = new ReturnModel(); 

    BufferedReader in = null; 
    String data = null; 
    Bundle gotData = getIntent().getExtras(); 
    if (gotData != null) { 
     GotPass = gotData.getString("key!"); 
     GotUname = gotData.getString("key!!"); 
    } 

    SharedPreferences settings = getSharedPreferences(PREFS_NAME, 0); 
    String username = settings.getString("key1", null); 
    String password = settings.getString("key2", null); 
    // username = "irock97"; // unremark to test like you got username from prefs.. 
    if (username != null && username.equals("irock97")) { 
     returnModel.setPassworderror(false); 
    } 
    else 
    { 
     returnModel.setPassworderror(true); 
     return returnModel; 
    } 

    HttpClient httpclient = new DefaultHttpClient(); 

    /* login.php returns true if username and password is equal to saranga */ 
    HttpPost httppost = new HttpPost("http://gta5news.com/login.php"); 

    try { 
     // Add user name and password 
     List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2); 
     nameValuePairs.add(new BasicNameValuePair("username", username)); 
     nameValuePairs.add(new BasicNameValuePair("password", password)); 
     httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs)); 

     // Execute HTTP Post Request 
     Log.w("HttpPost", "Execute HTTP Post Request"); 
     HttpResponse response = httpclient.execute(httppost); 
     in = new BufferedReader(new InputStreamReader(response.getEntity().getContent())); 
     StringBuffer sb = new StringBuffer(""); 
     String l = ""; 
     String nl = ""; 
     while ((l = in.readLine()) != null) { 
     sb.append(l + nl); 
     } 
     in.close(); 
     data = sb.toString(); 


     List<String> headlines = new ArrayList<String>(); 
     headlines.add(data); 
     returnModel.setheadlines(headlines); 
    } 
    catch (ClientProtocolException e) { 
     e.printStackTrace(); 
    } 
    catch (IOException e) { 
     e.printStackTrace(); 
    } 

    return returnModel; 
    } 


    public class ReturnModel { 
    private List<String> headlines; 
    private boolean passworderror; 

    public List<String> getheadlines() { 
     return headlines; 
    } 

    public void setheadlines(List<String> headlines) { 
     this.headlines = headlines; 
    } 

    public boolean getPassworderror() { 
     return passworderror; 
    } 

    public void setPassworderror(boolean passworderror) { 
     this.passworderror = passworderror; 
    } 
    } 

} 

Answer 2

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

통화 Looper.Prepare()()

편집 : 어쨌든, 여기에 코드와 로그 캣입니다 또한 다른 모든 사람들이 알 수 있듯이 UI 스레드에서 Toast를 실행해야합니다.

Answer 3

이 오류는 일반적으로 UI 스레드 외부에서 UI를 수정하려고 할 때 발생합니다. 보고있는 오류는 Toast.makeText() 호출로 인해 발생합니다.

runOnUiThread(new Runnable() { 
    public void run() { 
     Toast.makeText(/* etc */).show(); 
    } 
} 

Answer 4

당신은하지 메인 UI 스레드에서 Toast.makeText을 요구하고있다 : 당신은 그것을 다시 쓸 수 있습니다. 이 스택 트레이스에 기록되면

:

Looper.prepare라고하지 스레드 내부 핸들러를 만들 수 없습니다(). 내부적으로 Toast.makeText는 자체적으로 사용하기 위해 처리기를 생성합니다.

테스트 목적으로 사용하는 경우 Log.v 또는 그와 유사한 것을 사용하는 것이 좋습니다. 당신이 정말로 토스트를 확인하려면

, 다음 runOnUIThread(), 또는 더 나은 사용하려고 :

publishProgress (...)를;

및

onProgressUpdate() AsyncTasks에서 사용할

.