为什么 tts 不更改 Android 片段中的语言但在 Activity 中工作正常？

Question

所以我一直在尝试更改片段内的 TTS 语言，但它不起作用，但相同的代码在 MainActivity 内工作正常。我不明白为什么。我检查了其他解决方案，但 none 对我有用。我尝试了不同的 solution , solution，但即使这样也行不通。

public class HomeFragment extends Fragment  implements TextToSpeech.OnInitListener{
    private static final int TTS_DATA_CHECK = 1;
    private TextToSpeech engine;
    private SettingsViewModel settingsViewModel;
    private EditText textMsg;
    private Button button;

    public View onCreateView(@NonNull LayoutInflater inflater,
                             ViewGroup container, Bundle savedInstanceState) {
        engine = new TextToSpeech(getContext(),this);
        settingsViewModel = new ViewModelProvider(getActivity()).get(SettingsViewModel.class);
        return inflater.inflate(R.layout.fragment_home, container, false);
    }

    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        textMsg = view.findViewById(R.id.textMsg);
        button = view.findViewById(R.id.playButton);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                engine.speak(textMsg.getText().toString(), TextToSpeech.QUEUE_FLUSH, null,null);
            }
        });
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        settingsViewModel.getLanguage().observe(getViewLifecycleOwner(), new Observer<String>() {
            @Override
            public void onChanged(String s) {
                Log.d("LANGUAGE_SELECTED",s);
                switch (s){
                    case "ENGLISH":
                        engine.setLanguage(Locale.ENGLISH);
                        break;
                    case "FRENCH":
                        engine.setLanguage(Locale.FRENCH);
                        break;
                }
            }
        });
    }

    @Override
    public void onInit(int status) {
        if(status==TextToSpeech.SUCCESS){
            int result = engine.setLanguage(Locale.ENGLISH);
            if(result == TextToSpeech.LANG_MISSING_DATA
                    || result== TextToSpeech.LANG_NOT_SUPPORTED){
                Toast.makeText(getContext(),"Not supported",Toast.LENGTH_LONG).show();
            }
        }else{
            Toast.makeText(getContext(),"TTS is missing",Toast.LENGTH_LONG).show();
        }
    }

}

Answer 1

首先你需要像这样在mainactivity中初始化TTS -

public class MainActivity extends AppCompatActivity implements TextToSpeech.OnInitListener {
 
    private static final int TTS_DATA_CHECK = 101;
    static TextToSpeech engine;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        engine = new TextToSpeech(this,this);
    }

    
    @Override
    public final void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == 101)
        {
            if (resultCode != TextToSpeech.Engine.CHECK_VOICE_DATA_PASS)
            {
                final Intent tnt = new Intent(TextToSpeech.Engine.ACTION_INSTALL_TTS_DATA);
                startActivity(tnt);
            }
        }
    }

    @Override
    public void onInit(int status) {
        if(status==TextToSpeech.SUCCESS){
            if(TTS_DATA_CHECK == TextToSpeech.LANG_MISSING_DATA
              || TTS_DATA_CHECK== TextToSpeech.LANG_NOT_SUPPORTED){
                Toast.makeText(this,"Not supported",Toast.LENGTH_LONG).show();
            }
        }
    }

    static public TextToSpeech getInstance() {
        return engine;
    }

}

然后你必须像这样在Fragment中调用TTS实例。请注意，MainActivity 是给定 Fragment 的父 activity。

现在将您的 Fragment 中的以下代码替换为此代码 -

@Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        Log.d("VMA","OnActivityCreated");
        settingsViewModel.getLanguage().observe(getViewLifecycleOwner(), new Observer<String>() {
            @Override
            public void onChanged(String s) {
                Log.d("VMA","LANGUAGE_SELECTED " + s);
                switch (s){
                    case "FRENCH":
                        MainActivity.getInstance().setLanguage(Locale.FRENCH);
                        break;
                    case "ENGLISH":
                        MainActivity.getInstance().setLanguage(Locale.ENGLISH);
                        break;
                }
            }
        });
    }  

另外，您可以从 Fragment 中删除其余的 TTS 代码。你不再那样了。