四：语音识别
最后更新于：2022-04-01 06:42:14
Google的语音识别是有目共睹的，所以Android上面也是沾了大光了，用起来简单至极。
过程如下：
1、启动语音识别Activity
2、这里处理语音（传到google服务器处理）
3、结果以Acitivity的结果返回（onActivityResult）
主要用到的类为[android.speech.RecognizerIntent](http://developer.android.com/reference/android/speech/RecognizerIntent.html)
下面的例子参考了API Demo。
~~~
package com.linc;
import java.util.ArrayList;
import java.util.List;
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.Button;
import android.widget.TextView;
public class VoiceRecognitionDemoActivity extends Activity {
private static final String TAG = "VoiceRecognition";
private static final int VOICE_RECOGNITION_REQUEST_CODE = 1234;
private TextView textView;
private Button button;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
initWidget();
// Check to see if a recognition activity is present
PackageManager pm = getPackageManager();
List activities = pm.queryIntentActivities(
new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH), 0);
if (activities.size() != 0) {
button.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
startVoiceRecognitionActivity();
}
});
} else {
button.setEnabled(false);
button.setText("Recognizer not present");
}
}
private void initWidget()
{
textView = (TextView)findViewById(R.id.tv);
button = (Button)findViewById(R.id.btn);
}
/**
* Fire an intent to start the speech recognition activity.
*/
private void startVoiceRecognitionActivity() {
Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
// Display an hint to the user about what he should say.
intent.putExtra(RecognizerIntent.EXTRA_PROMPT, "请说标准普通话");//注意不要硬编码
// Given an hint to the recognizer about what the user is going to say
intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,
RecognizerIntent.LANGUAGE_MODEL_FREE_FORM);
// Specify how many results you want to receive. The results will be sorted
// where the first result is the one with higher confidence.
intent.putExtra(RecognizerIntent.EXTRA_MAX_RESULTS, 5);//通常情况下，第一个结果是最准确的。
startActivityForResult(intent, VOICE_RECOGNITION_REQUEST_CODE);
}
@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 matches = data.getStringArrayListExtra(
RecognizerIntent.EXTRA_RESULTS);
StringBuilder stringBuilder = new StringBuilder();
int Size = matches.size();
for(int i=0;i
{
stringBuilder.append(matches.get(i));
stringBuilder.append("\n");
}
textView.setText(stringBuilder);
}
super.onActivityResult(requestCode, resultCode, data);
}
}
~~~
结论：
在wifi（家里的，1兆带宽）状态下，识别速度飞快。
语音包是买手机时预装好的。
识别率很高。中文、英文、数字都能很好的识别。
用手机的gprs，效果不尽如人意。几次识别都用了30秒左右的时间，体验很糟。