Android教程之Android自带的语音识别例子初探

主题：Android教程之Android自带的语音识别例子初探

版权申明：http://yarin.javaeye.com/blog/453262   

语音识别技术是在Android SDK1.5中才加入的（RecognizerIntent），这里我们简单的分析一下自带的api例子，其实它就是通过一个Intent的Action动作来完成的。主要有以下两种模式:

ACTION_RECOGNIZE_SPEECH：一般语音识别，在这种模式下我们可以捕捉到语音的处理后的文字列。

ACTION_WEB_SEARCH：网络搜索

该例子同样是使用ACTION_RECOGNIZE_SPEECH模式，我们需要实现onActivityResult方法，当语音识别结束之后的回调函数。

好了，废话不多说，看下面的代码，我加入了注释，重要的本来就不多几行。

package com.example.android.apis.app;

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;

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);

        setContentView(R.layout.voice_recognition);

        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");
        }
    }


    public void onClick(View v)
    {
        if (v.getId() == R.id.btn_speak)
        {
            startVoiceRecognitionActivity();
        }
    }

    private void startVoiceRecognitionActivity()
    {
        //通过Intent传递语音识别的模式
        Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
        //语言模式和自由形式的语音识别
        intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL, RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
        //提示语音开始
        intent.putExtra(RecognizerIntent.EXTRA_PROMPT, "Speech recognition demo");
        //开始执行我们的Intent、语音识别
        startActivityForResult(intent, VOICE_RECOGNITION_REQUEST_CODE);
    }


    //当语音结束时的回调函数onActivityResult
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data)
    {
        if (requestCode == VOICE_RECOGNITION_REQUEST_CODE && resultCode == RESULT_OK)
        {
            // 取得语音的字符
            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);
    }
}

package com.example.android.apis.app;

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;

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);

        setContentView(R.layout.voice_recognition);

        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");
		}
    }


    public void onClick(View v)
	{
		if (v.getId() == R.id.btn_speak)
		{
			startVoiceRecognitionActivity();
		}
	}

    private void startVoiceRecognitionActivity()
	{
    	//通过Intent传递语音识别的模式
		Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
		//语言模式和自由形式的语音识别
		intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL, RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
		//提示语音开始
		intent.putExtra(RecognizerIntent.EXTRA_PROMPT, "Speech recognition demo");
		//开始执行我们的Intent、语音识别
		startActivityForResult(intent, VOICE_RECOGNITION_REQUEST_CODE);
	}


    //当语音结束时的回调函数onActivityResult
    @Override
	protected void onActivityResult(int requestCode, int resultCode, Intent data)
	{
		if (requestCode == VOICE_RECOGNITION_REQUEST_CODE && resultCode == RESULT_OK)
		{
			// 取得语音的字符
			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);
	}
} 

当然这里需要设备的支持，所以模拟器是没有效果的！

实际上在没有设备时会跑出ActivityNotFoundException异常。

这个例子很简单，到此为止，谢谢！