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我正在分析这个 Voice Recognizer 类，需要帮助理解代码中的这一行。下面一行的作用是什么？它是否会创建设备上加载的 android 平台上所有活动的列表？我特别发现解决信息有点令人困惑......

列出活动 = pm.queryIntentActivities(new Intent(

这是上下文中使用的代码

package com.example.voicerecognitionactivity;

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

import android.app.Activity;
import android.app.SearchManager;
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.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Spinner;
import android.widget.Toast;

public class VoiceRecognitionActivity extends Activity {
    private static final int VOICE_RECOGNITION_REQUEST_CODE = 1001;

    private EditText metTextHint;
    private ListView mlvTextMatches;
    private Spinner msTextMatches;
    private Button mbtSpeak;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        metTextHint = (EditText) findViewById(R.id.etTextHint);
        mlvTextMatches = (ListView) findViewById(R.id.lvTextMatches);
        msTextMatches = (Spinner) findViewById(R.id.sNoOfMatches);
        mbtSpeak = (Button) findViewById(R.id.btSpeak);
    }

    public void checkVoiceRecognition() {
        // Check if voice recognition is present
        PackageManager pm = getPackageManager();
        List<ResolveInfo> activities = pm.queryIntentActivities(new Intent(
                RecognizerIntent.ACTION_RECOGNIZE_SPEECH), 0);
        if (activities.size() == 0) {
            mbtSpeak.setEnabled(false);
            Toast.makeText(this, "Voice recognizer not present",
                    Toast.LENGTH_SHORT).show();
        }
    }

    public void speak(View view) {
        Intent intent = new Intent(RecognizerIntent.ACTION_RECOGNIZE_SPEECH);
        // Specify the calling package to identify your application
        intent.putExtra(RecognizerIntent.EXTRA_CALLING_PACKAGE, getClass()
                .getPackage().getName());

        // Display an hint to the user about what he should say.
        intent.putExtra(RecognizerIntent.EXTRA_PROMPT, metTextHint.getText()
                .toString());

        // Given an hint to the recognizer about what the user is going to say
        intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL,
                RecognizerIntent.LANGUAGE_MODEL_WEB_SEARCH);

        // If number of Matches is not selected then return show toast message
        if (msTextMatches.getSelectedItemPosition() == AdapterView.INVALID_POSITION) {
            Toast.makeText(this, "Please select No. of Matches from spinner",
                    Toast.LENGTH_SHORT).show();
            return;
        }

        int noOfMatches = Integer.parseInt(msTextMatches.getSelectedItem()
                .toString());
        // 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, noOfMatches);

        startActivityForResult(intent, VOICE_RECOGNITION_REQUEST_CODE);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == VOICE_RECOGNITION_REQUEST_CODE)

            //If Voice recognition is successful then it returns RESULT_OK
            if(resultCode == RESULT_OK) {

                ArrayList<String> textMatchList = data
                .getStringArrayListExtra(RecognizerIntent.EXTRA_RESULTS);

                if (!textMatchList.isEmpty()) {
                    // If first Match contains the 'search' word
                    // Then start web search.
                    if (textMatchList.get(0).contains("search")) {

                        String searchQuery = textMatchList.get(0).replace("search",
                        " ");
                        Intent search = new Intent(Intent.ACTION_WEB_SEARCH);
                        search.putExtra(SearchManager.QUERY, searchQuery);
                        startActivity(search);
                    } else {
                        // populate the Matches
                        mlvTextMatches
                        .setAdapter(new ArrayAdapter<String>(this,
                                android.R.layout.simple_list_item_1,
                                textMatchList));
                    }

                }
            //Result code for various error.   
            }else if(resultCode == RecognizerIntent.RESULT_AUDIO_ERROR){
                showToastMessage("Audio Error");
            }else if(resultCode == RecognizerIntent.RESULT_CLIENT_ERROR){
                showToastMessage("Client Error");
            }else if(resultCode == RecognizerIntent.RESULT_NETWORK_ERROR){
                showToastMessage("Network Error");
            }else if(resultCode == RecognizerIntent.RESULT_NO_MATCH){
                showToastMessage("No Match");
            }else if(resultCode == RecognizerIntent.RESULT_SERVER_ERROR){
                showToastMessage("Server Error");
            }
        super.onActivityResult(requestCode, resultCode, data);
    }
    void showToastMessage(String message){
        Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
    }
}
4

1 回答 1

0

我认为，这是检查语音识别是否存在的最简单方法：

Intent intent = new Intent(
                        RecognizerIntent.ACTION_RECOGNIZE_SPEECH);

                intent.putExtra(RecognizerIntent.EXTRA_LANGUAGE_MODEL, "en-US");

                try {
                    startActivityForResult(intent, RESULT_SPEECH);
                } catch (ActivityNotFoundException a) {
                    Toast t = Toast.makeText(getApplicationContext(),
                            "Opps! Your device doesn't support Speech to Text",
                            Toast.LENGTH_LONG);
                    t.show();
                }

在那之后：

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        switch (requestCode) {
        case RESULT_SPEECH: {
            if (resultCode == RESULT_OK && null != data) {

                ArrayList<String> text = data
                        .getStringArrayListExtra(RecognizerIntent.EXTRA_RESULTS);

                    et_task_notes.setText(text.get(0));
            }
            break;
        }
        }
    }
于 2013-08-25T18:34:15.893 回答