Android錯誤：必須從UI線程調用方法gettext當前推斷的線程正在工作

Question

嗨我所有新來的Android和我正在建立一個英語到德語翻譯器的應用程序，我得到上述錯誤的代碼行： 可以請幫助我如何解決這個問題。

package com.exmaple.android.lang_trans; 

import java.util.Locale; 

import android.app.Activity; 

import android.os.AsyncTask; 

import android.os.Bundle; 

import android.speech.tts.TextToSpeech; 

import android.speech.tts.TextToSpeech.OnInitListener; 

import android.util.Log; 

import android.view.View; 

import android.view.View.OnClickListener; 

import android.widget.Button; 

import android.widget.EditText; 

import android.widget.TextView; 

import com.exmaple.android.lang_trans.R; 

import com.memetix.mst.language.Language; 

import com.memetix.mst.translate.Translate; 

public class MainActivity extends Activity implements OnInitListener { 

    private TextToSpeech tts; 

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

     tts = new TextToSpeech(this, this); 
     ((Button) findViewById(R.id.bSpeak)).setOnClickListener(new OnClickListener() { 

      @Override 
      public void onClick(View v) { 
       // TODO Auto-generated method stub 
       speakOut(((TextView) findViewById(R.id.tvTranslatedText)).getText().toString()); 
      } 
     }); 

     ((Button) findViewById(R.id.bTranslate)).setOnClickListener(new OnClickListener() { 

      @Override 
      public void onClick(View v) { 
       // TODO Auto-generated method stub 


       class bgStuff extends AsyncTask<Void, Void, Void> { 

        String translatedText = ""; 

        @Override 
        protected Void doInBackground(Void... params) { 
         // TODO Auto-generated method stub 
         try { 
          //below line is throwing the error 
          String text = ((EditText) findViewById(R.id.etUserText)).getText().toString(); 
          translatedText = translate(text); 
         } catch (Exception e) { 
          // TODO Auto-generated catch block 
          e.printStackTrace(); 
          translatedText = e.toString(); 
         } 

         return null; 
        } 

        @Override 
        protected void onPostExecute(Void result) { 
         // TODO Auto-generated method stub 
         ((TextView) findViewById(R.id.tvTranslatedText)).setText(translatedText); 
         super.onPostExecute(result); 
        } 

       } 

       new bgStuff().execute(); 
      } 
     }); 
    } 

    public String translate(String text) throws Exception { 


     // Set the Client ID/Client Secret once per JVM. It is set statically and applies to all services 
     Translate.setClientId("CLIENT ID"); //Change this 
     Translate.setClientSecret("CLIENT SECRET"); //change 


     String translatedText = ""; 

     translatedText = Translate.execute(text, Language.GERMAN); 

     return translatedText; 
    } 

    @Override 
    public void onInit(int status) { 
     // TODO Auto-generated method stub 
     if (status == TextToSpeech.SUCCESS) { 

      int result = tts.setLanguage(Locale.GERMAN); 

      if (result == TextToSpeech.LANG_MISSING_DATA 
        || result == TextToSpeech.LANG_NOT_SUPPORTED) { 
       Log.e("TTS", "This Language is not supported"); 
      } else { 

       //speakOut("Ich"); 
      } 

     } else { 
      Log.e("TTS", "Initilization Failed!"); 
     } 
    } 

    private void speakOut(String text) { 
     tts.speak(text, TextToSpeech.QUEUE_FLUSH, null); 
    } 

} 

Answer 1

你的問題是，你正在訪問的UI元素在比UI線程的線程上的Android系統不允許

you cannot update the UI from any thread other than the UI thread or the "main" thread.

https://developer.android.com/guide/components/processes-and-threads.html#WorkerThreads

所以，你可以改變你的onClick功能以下內容：

((Button) findViewById(R.id.bTranslate)).setOnClickListener(new OnClickListener() { 

    @Override 
    public void onClick(View v) { 
     class bgStuff extends AsyncTask<String, Void, String> { 
      @Override 
      protected String doInBackground(String... params) { 
       // TODO Auto-generated method stub 
       try { 
        if (params.length > 0) { 
         return translate(params[0]); 
        } 
       } catch (Exception e) { 
        e.printStackTrace(); 
        return e.toString(); 
       } 
       return null; 
      } 

      @Override 
      protected void onPostExecute(String result) { 
       ((TextView) findViewById(R.id.tvTranslatedText)).setText(result); 
      } 
     } 

     new bgStuff().execute(((EditText) findViewById(R.id.etUserText)).getText().toString()); 
    } 
});