Android Studio錯誤：“必須從UI線程調用方法getText，當前推斷的線程為worker

Question

我有一個關於gettext（）的問題，Android Studio說“必須從UI線程調用方法getText，當前推斷的線程是worker”。 有人可以幫助我解決這個問題嗎？ 謝謝！

package com.ibm.watsonvoicetts;

import android.os.AsyncTask;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

import com.ibm.watson.developer_cloud.android.library.audio.StreamPlayer;
import com.ibm.watson.developer_cloud.text_to_speech.v1.TextToSpeech;
import com.ibm.watson.developer_cloud.text_to_speech.v1.model.Voice;

public class MainActivity extends AppCompatActivity {

TextView textView;
EditText editText;
Button button;

StreamPlayer streamPlayer;


private TextToSpeech initTextToSpeechService(){
    TextToSpeech service = new TextToSpeech();
    String username = "";
    String password = "";
    service.setUsernameAndPassword(username, password);
    return service;
}

private class WatsonTask extends AsyncTask<String, Void, String> {
    @Override
    protected String doInBackground(String... textToSpeak) {
        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                textView.setText("running the Watson thread");
            }
        });

        TextToSpeech textToSpeech = initTextToSpeechService();
        streamPlayer = new StreamPlayer();
        streamPlayer.playStream(textToSpeech.synthesize(
                String.valueOf(editText.getText()),【**here is the problem**】
                Voice.EN_MICHAEL).execute());

        return "text to speech done";
    }

    @Override
    protected void onPostExecute(String result) {
        textView.setText("TTS status: " + result);
    }

}

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

    editText = (EditText) findViewById(R.id.editText);
    button = (Button) findViewById(R.id.button);
    textView = (TextView) findViewById(R.id.textView);

    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            System.out.println("the text to speech: " + editText.getText());
            textView.setText("TTS: " + editText.getText());

            WatsonTask task = new WatsonTask();
            task.execute(new String[]{});


        }
    });
}

}

Answer 1

您不應像這樣做那樣從AsyncTask調用getText 。 解決方案是將值傳遞到任務的構造函數中。

更改

WatsonTask task = new WatsonTask(editText.getText());

和

private class WatsonTask extends AsyncTask<String, Void, String> {
    private final String text;
    public WatsonTask(String text) {
        super();
        this.text = text;
    }

和

streamPlayer.playStream(textToSpeech.synthesize(
            String.valueOf(text),
            Voice.EN_MICHAEL).execute());

Answer 2

doInBackground（）方法在UI線程中以外的其他線程上運行。

streamPlayer.playStream(textToSpeech.synthesize(
                String.valueOf(editText.getText()),【**here is the problem**】
                Voice.EN_MICHAEL).execute());

您正在此doInBackground（）方法中調用edittext的getText（）方法。 這就是為什么會出錯。 任何與視圖相關的工作，我們都必須在UI線程中完成。

您可以做的一件事，就是將這段代碼放在runOnUiThread中。