在旋转器中显示TTS可用语言

Question

我最近开始编写android程序，我想看看有哪些语言的文本到语音可用在设备上，并显示在一个旋转器，但我遇到了一个非常奇怪的问题。

下面是代码的相关部分：

package com.example.dshawn.ttsapp;

import android.speech.tts.TextToSpeech;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.Toast;

import java.util.*;

public class MainActivity extends AppCompatActivity implements

        AdapterView.OnItemSelectedListener {
    private TextToSpeech mTTS;
    Locale[] locales = Locale.getAvailableLocales();
    List<Locale> localeList = new ArrayList<Locale>();
    List<String> country=  new ArrayList<String>();
    List<String> asdf=  new ArrayList<String>();


    int sum=0;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mTTS = new TextToSpeech(this, new TextToSpeech.OnInitListener() {
            @Override
            public void onInit(int i) {
                if (i==TextToSpeech.SUCCESS){
                    for (Locale locale : locales) {
                        int res = mTTS.isLanguageAvailable(locale);
                        if (res == TextToSpeech.LANG_COUNTRY_AVAILABLE) {
                            sum++;
                            localeList.add(locale);
                            country.add(locale.getDisplayName());
                        }
                    }
                    asdf.add(Integer.toString(sum));


                }

            }
        });
        //Getting the instance of Spinner and applying OnItemSelectedListener on it

        Spinner spin = (Spinner) findViewById(R.id.spinner);
        spin.setOnItemSelectedListener(this);

        //Creating the ArrayAdapter instance having the country list
        ArrayAdapter<String> aa = new  ArrayAdapter<String>(this,android.R.layout.simple_spinner_item,country);
        aa.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        //Setting the ArrayAdapter data on the Spinner
        spin.setAdapter(aa);

    }

    //Performing action onItemSelected and onNothing selected
    @Override
    public void onItemSelected(AdapterView<?> arg0, View arg1, int position, long id) {
        Toast.makeText(getApplicationContext(),country.get(position) , Toast.LENGTH_LONG).show();
    }
    @Override
    public void onNothingSelected(AdapterView<?> arg0) {
        // TODO Auto-generated method stub
    }
}

在这个TTS初始化之后，我尝试并打印sum，它显示为0。我尝试通过执行类似String=country.get(1)的操作来访问localeList和country中的元素；它会在编译器中给出一个错误，说我试图访问的索引不存在，列表中有0个元素。在这一点上，设备上似乎没有可用的语言，但奇怪的是，当我通过ArrayAdapter将国家数组列表放入我的旋转器下拉菜单时，我设备上实际可用的国家确实会显示在旋转器菜单中，但它是坏的，这里是我的意思的gif：

旋转器永远不会进入我的onItemSelected侦听器，并且项在单击后不会显示在旋转器中。我进入了设备的设置，那些显示的确实是该设备上TTS的可用区域设置。当我删除代码中似乎从未访问过的“if(res==TextToSpeech.lang_Country_Available)”部分时，旋转器下拉菜单中就没有任何内容了。所以它明显地以某种方式抓取了可用的区域设置，但当我试图访问arraylist时，它的行为就像它是空的，但它以某种方式使用“空的”arraylist并将正确的国家/地区放入旋转框中，但旋转框被破坏了，大概是因为arraylist被破坏了，因为我对手工填充的arraylist尝试了同样的操作，元素正常显示，我可以正常选择它。

这里有什么问题？我已经尝试了我能想到的一切，我只知道问题出在TTS初始化部分。

基本上，我无法访问在TTS的“oninit”方法中设置或添加的任何项，这也会导致我的旋转器中断。

Answer 1

我认为问题是您在列表填充之前（因为TTS还没有初始化）创建适配器（使用国家列表）。

public class MainActivity extends AppCompatActivity implements AdapterView.OnItemSelectedListener {

    private TextToSpeech mTTS;
    Locale[] locales = Locale.getAvailableLocales();
    List<Locale> localeList = new ArrayList<Locale>();
    List<String> country = new ArrayList<String>();

    // * - Move these two variables out here
    ArrayAdapter<String> aa;
    Spinner spin;

    int sum = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        Log.i("XXX", "onCreate() was called");
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mTTS = new TextToSpeech(this, new TextToSpeech.OnInitListener() {
            @Override
            public void onInit(int i) {
                if (i == TextToSpeech.SUCCESS) {
                    // * - delay important tasks until TTS is initialized
                    startWhenTTSIsInitialized();
                }
            }
        });

        //Getting the instance of Spinner and applying OnItemSelectedListener on it
        spin = (Spinner) findViewById(R.id.spinner);

    }

    private void startWhenTTSIsInitialized() {

        Log.i("XXX", "startWhenTTSIsInitialized() was called");
        for (Locale locale : locales) {
            int res = mTTS.isLanguageAvailable(locale);
            if (res == TextToSpeech.LANG_COUNTRY_AVAILABLE) {
                sum++;
                localeList.add(locale);
                // * - 'country' is used to populate the adapter, so
                // this line must come first
                country.add(locale.getDisplayName());
            }
        }

        //Creating the ArrayAdapter instance having the country list
        // * - now it's safe to set the adapter because the country list has been populated
        aa = new ArrayAdapter<String>(this, android.R.layout.simple_spinner_item, country);
        aa.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        //Setting the ArrayAdapter data on the Spinner
        spin.setAdapter(aa);
        spin.setOnItemSelectedListener(this);

    }

    //Performing action onItemSelected and onNothing selected
    @Override
    public void onItemSelected(AdapterView<?> arg0, View arg1, int position, long id) {

        Log.i("XXX", "onItemSelected() was called");
        Toast.makeText(getApplicationContext(), country.get(position), Toast.LENGTH_LONG).show();

    }

    @Override
    public void onNothingSelected(AdapterView<?> arg0) {

        // TODO Auto-generated method stub

    }

}