Android 轻松实现语音识别

/* 
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.example.android.apis.app;

import com.example.android.apis.R;

import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.os.Bundle;
import android.speech.RecognizerIntent;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;

import java.util.ArrayList;
import java.util.List;

/**
 * Sample code that invokes the speech recognition intent API.
 */
public class VoiceRecognition extends Activity implements OnClickListener {
    
    private static final int VOICE_RECOGNITION_REQUEST_CODE = 1234;
    
    private ListView mList;

    /**
     * Called with the activity is first created.
     */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Inflate our UI from its XML layout description.
        setContentView(R.layout.voice_recognition);

        // Get display items for later interaction
        Button speakButton = (Button) findViewById(R.id.btn_speak);
        
        mList = (ListView) findViewById(R.id.list);

        // Check to see if a recognition activity is present
        PackageManager pm = getPackageManager();
        List<ResolveInfo> activities = pm.queryIntentActivities(
                new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH), 0);
        if (activities.size() != 0) {
            speakButton.setOnClickListener(this);
        } else {
            speakButton.setEnabled(false);
            speakButton.setText("Recognizer not present");
        }
    }

    /**
     * Handle the click on the start recognition button.
     */
    public void onClick(View v) {
        if (v.getId() == R.id.btn_speak) {
            startVoiceRecognitionActivity();
        }
    }

    /**
     * Fire an intent to start the speech recognition activity.
     */
    private void startVoiceRecognitionActivity() {
        Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
        intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,
                RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
        intent.putExtra(RecognizerIntent.EXTRA_PROMPT, "Speech recognition demo");
        startActivityForResult(intent, VOICE_RECOGNITION_REQUEST_CODE);
    }

    /**
     * Handle the results from the recognition activity.
     */
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == VOICE_RECOGNITION_REQUEST_CODE && resultCode == RESULT_OK) {
            // Fill the list view with the strings the recognizer thought it could have heard
            ArrayList<String> matches = data.getStringArrayListExtra(
                    RecognizerIntent.EXTRA_RESULTS);
            mList.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,
                    matches));
        }

        super.onActivityResult(requestCode, resultCode, data);
    }
}