java - Pocketsphinx Demo 中空指针异常切换到搜索

Question

我想在 android 中开发一个语音识别器。我用过 this thread和 this video在 Android 设备中使用语音识别。
这是我的代码:
MainActivity.java:

package com.example.pocket_sphinx;

import edu.cmu.pocketsphinx.Hypothesis;
import edu.cmu.pocketsphinx.RecognitionListener;
import android.os.Bundle;
import android.app.Activity;
import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import static android.widget.Toast.makeText;
import static edu.cmu.pocketsphinx.SpeechRecognizerSetup.defaultSetup;
import android.os.AsyncTask;
import android.util.Log;
import android.widget.TextView;
import android.widget.Toast;
import edu.cmu.pocketsphinx.Assets;
import edu.cmu.pocketsphinx.SpeechRecognizer;

public class MainActivity extends Activity implements RecognitionListener {

       private static final String KWS_SEARCH = "wakeup";
        private static final String DICTATION_SEARCH = "digits";

        private static final String KEYPHRASE = "oh mighty computer";

        private SpeechRecognizer recognizer;
        private HashMap<String, Integer> captions;

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

            // Prepare the data for UI
            captions = new HashMap<String, Integer>();

            setContentView(R.layout.activity_main);
            ((TextView) findViewById(R.id.caption_text))
                    .setText("Preparing the recognizer");

            // Recognizer initialization is a time-consuming and it involves IO,
            // so we execute it in async task

            new AsyncTask<Void, Void, Exception>() {
                @Override
                protected Exception doInBackground(Void... params) {
                    try {
                        Assets assets = new Assets(MainActivity.this);

                        File assetDir = assets.syncAssets();

                        setupRecognizer(assetDir);

                        recognizer.startListening(KWS_SEARCH);

                    } catch (IOException e) {
                        return e;
                    }
                    return null;
                }

                @Override
                protected void onPostExecute(Exception result) {
                    if (result != null) {
                        ((TextView) findViewById(R.id.caption_text))
                                .setText("Failed to init recognizer " + result);
                    } else {
                        switchSearch(KWS_SEARCH);
                    }
                }
            }.execute();
        }

        @Override
        public void onPartialResult(Hypothesis hypothesis) {
            String text = hypothesis.getHypstr();
            Log.d("Spoken text",text);

            if (text.equals(KEYPHRASE))
                switchSearch(DICTATION_SEARCH);

            else
                ((TextView) findViewById(R.id.result_text)).setText(text);
        }

        @Override
        public void onResult(Hypothesis hypothesis) {
            ((TextView) findViewById(R.id.result_text)).setText("");
            if (hypothesis != null) {
                String text = hypothesis.getHypstr();
                makeText(getApplicationContext(), text, Toast.LENGTH_SHORT).show();
            }
        }

        @Override
        public void onBeginningOfSpeech() {
        }

        @Override
        public void onEndOfSpeech() {
            Log.d("end","In end of speech");
            if (DICTATION_SEARCH.equals(recognizer.getSearchName()))
                switchSearch(KWS_SEARCH);
        }

        private void switchSearch(String searchName) {
            recognizer.stop();
            recognizer.startListening(searchName);
            String caption = getResources().getString(captions.get(searchName));
            ((TextView) findViewById(R.id.caption_text)).setText(caption);
        }

        private void setupRecognizer(File assetsDir) {
            File modelsDir = new File(assetsDir, "models");
            recognizer = defaultSetup()
                    .setAcousticModel(new File(modelsDir, "hmm/en-us"))
                    .setDictionary(new File(modelsDir, "dict/cmu07a.dic"))
                    .setRawLogDir(assetsDir).setKeywordThreshold(1e-20f)
                    //.setFloat("-beam", 1e-30f)
                    .getRecognizer();
            recognizer.addListener(this);

            // Create keyword-activation search.
            recognizer.addKeyphraseSearch(KWS_SEARCH, KEYPHRASE);

            // Create language model search.
            File languageModel = new File(modelsDir, "lm/weather.dmp");
            recognizer.addNgramSearch(DICTATION_SEARCH, languageModel);
        }
    }

其实我不知道如何使用它。
运行后，它抛出运行时异常。我已经发布了我的代码的 logcat:

03-08 14:02:53.040: I/cmusphinx(17309): INFO: ngram_search_fwdtree.c(99): 788 unique initial diphones
03-08 14:02:53.230: I/cmusphinx(17309): INFO: ngram_search_fwdtree.c(148): 0 root, 0 non-root channels, 58 single-phone words
03-08 14:02:53.250: I/cmusphinx(17309): INFO: ngram_search_fwdtree.c(186): Creating search tree
03-08 14:02:53.470: I/cmusphinx(17309): INFO: ngram_search_fwdtree.c(192): before: 0 root, 0 non-root channels, 58 single-phone words
03-08 14:02:55.630: I/cmusphinx(17309): INFO: ngram_search_fwdtree.c(326): after: max nonroot chan increased to 2230
03-08 14:02:55.630: I/cmusphinx(17309): INFO: ngram_search_fwdtree.c(339): after: 253 root, 2102 non-root channels, 13 single-phone words
03-08 14:02:55.630: I/cmusphinx(17309): INFO: ngram_search_fwdflat.c(157): fwdflat: min_ef_width = 4, max_sf_win = 25
03-08 14:02:57.130: W/dalvikvm(17309): threadid=2: spin on suspend #1 threadid=11 (pcf=0)
03-08 14:02:57.140: W/dalvikvm(17309): threadid=2: spin on suspend resolved in 1010 msec
03-08 14:02:57.150: D/-heap(17309): GC_CONCURRENT freed 417K, 8% free 7863K/8455K, paused 14ms+1015ms, total 1597ms
03-08 14:02:57.210: I/SpeechRecognizer(17309): Start recognition "wakeup"
03-08 14:02:57.390: I/cmusphinx(17309): INFO: pocketsphinx.c(863): Writing raw audio log file: /mnt/sdcard/Android/data/com.example.pocket_sphinx/files/sync/000000000.raw
03-08 14:02:57.890: I/SpeechRecognizer(17309): Stop recognition
03-08 14:02:57.890: I/SpeechRecognizer(17309): Start recognition "wakeup"
03-08 14:02:57.890: W/dalvikvm(17309): threadid=1: thread exiting with uncaught exception (group=0x41ab9450)
03-08 14:02:57.930: E/AndroidRuntime(17309): FATAL EXCEPTION: main
03-08 14:02:57.930: E/AndroidRuntime(17309): java.lang.NullPointerException
03-08 14:02:57.930: E/AndroidRuntime(17309):    at com.example.pocket_sphinx.MainActivity.switchSearch(MainActivity.java:108)
03-08 14:02:57.930: E/AndroidRuntime(17309):    at com.example.pocket_sphinx.MainActivity.access$2(MainActivity.java:105)
03-08 14:02:57.930: E/AndroidRuntime(17309):    at com.example.pocket_sphinx.MainActivity$1.onPostExecute(MainActivity.java:67)
03-08 14:02:57.930: E/AndroidRuntime(17309):    at com.example.pocket_sphinx.MainActivity$1.onPostExecute(MainActivity.java:1)
03-08 14:02:57.930: E/AndroidRuntime(17309):    at android.os.AsyncTask.finish(AsyncTask.java:631)
03-08 14:02:57.930: E/AndroidRuntime(17309):    at android.os.AsyncTask.access$600(AsyncTask.java:177)
03-08 14:02:57.930: E/AndroidRuntime(17309):    at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
03-08 14:02:57.930: E/AndroidRuntime(17309):    at android.os.Handler.dispatchMessage(Handler.java:99)
03-08 14:02:57.930: E/AndroidRuntime(17309):    at android.os.Looper.loop(Looper.java:137)
03-08 14:02:57.930: E/AndroidRuntime(17309):    at android.app.ActivityThread.main(ActivityThread.java:4802)
03-08 14:02:57.930: E/AndroidRuntime(17309):    at java.lang.reflect.Method.invokeNative(Native Method)
03-08 14:02:57.930: E/AndroidRuntime(17309):    at java.lang.reflect.Method.invoke(Method.java:511)
03-08 14:02:57.930: E/AndroidRuntime(17309):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:813)
03-08 14:02:57.930: E/AndroidRuntime(17309):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:580)
03-08 14:02:57.930: E/AndroidRuntime(17309):    at dalvik.system.NativeStart.main(Native Method)
03-08 14:02:57.940: I/cmusphinx(17309): INFO: pocketsphinx.c(863): Writing raw audio log file: /mnt/sdcard/Android/data/com.example.pocket_sphinx/files/sync/000000001.raw

Answer 1

您的代码有两个问题:

1)在doInBackground中开始搜索，在onPostExecute中再次开始同样的搜索，在onPostExecute中调用switchSearch就可以了

2) 您不填充字幕数组，而是在 switchSearch 方法中使用它。所以你得到空指针异常。可以注释掉

        String caption = getResources().getString(captions.get(searchName));
        ((TextView) findViewById(R.id.caption_text)).setText(caption);

如果您不打算使用字幕，请在 switchSearch 中