Android 使用ToneGenerator编写按键发声功能

package com.example.helloworld;

import android.media.AudioManager;
import android.media.ToneGenerator;
import android.os.Bundle;
import android.provider.Settings;
import android.app.Activity;
import android.content.Context;
import android.view.Menu;
import android.view.View;
import android.widget.Button;

public class MainActivity extends Activity {

    private Button btn1, btn2, btn3;
    private int value;
    private ToneGenerator mToneGenerator;
    private Object mToneGeneratorLock = new Object(); // 监视器对象锁
    private boolean mDTMFToneEnabled; // 按键操作音
    private static final int TONE_LENGTH_MS = 150; // 延迟时间
    private AudioManager mAudioManager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        btn1 = (Button) findViewById(R.id.button1);
        btn1.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                btn1.setText(value + "");
                playTone(value);
                value++;
                if (value > 9) {
                    value = 0;
                }
            }
        });

        btn2 = (Button) findViewById(R.id.button2);
        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                playTone(42); // *: 42
            }
        });

        btn3 = (Button) findViewById(R.id.button3);
        btn3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                playTone(35); // #: 35
            }
        });

        mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);

        mDTMFToneEnabled = Settings.System.getInt(getContentResolver(),
                Settings.System.DTMF_TONE_WHEN_DIALING, 1) == 1;

        synchronized (mToneGeneratorLock) {
            if (mToneGenerator == null) {
                try {
                    mToneGenerator = new ToneGenerator(
                            AudioManager.STREAM_MUSIC, 80);
                    setVolumeControlStream(AudioManager.STREAM_MUSIC);
                } catch (Exception e) {
                    e.printStackTrace();
                    mToneGenerator = null;
                }
            }
        }
    }

    // 播放按键声音
    void playTone(int tone) {
        if (!mDTMFToneEnabled) {
            return;
        }

        int ringerMode = mAudioManager.getRingerMode();
        if ((ringerMode == AudioManager.RINGER_MODE_SILENT)
                || (ringerMode == AudioManager.RINGER_MODE_VIBRATE)) {
            // 静音或者震动时不发出按键声音
            return;
        }

        synchronized (mToneGeneratorLock) {
            if (mToneGenerator == null) {
                return;
            }
            mToneGenerator.startTone(tone, TONE_LENGTH_MS); // 发声
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView1"
        android:layout_below="@+id/textView1"
        android:layout_marginTop="31dp"
        android:text="Button" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/button1"
        android:layout_alignBottom="@+id/button1"
        android:layout_centerHorizontal="true"
        android:text="Button" />

    <Button
        android:id="@+id/button3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/button2"
        android:layout_alignBottom="@+id/button2"
        android:layout_alignParentRight="true"
        android:text="Button" />

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.helloworld"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="19" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.helloworld.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>