Android录音与播放

本文转自:http://www.2cto.com/kf/201207/144738.html

 

Android多媒体框架包含获取和编码多种音频格式的支持,所以你可以轻松地把音频合并到你的应用中.如果设备支持,你可以使用MediaRecorder APIs 进行录音.

本章向你展示如何写一个应用从设备上的microphone获取音频,然后保存并回放.

注:Android模拟器不具有录音的能力,但是真实的设备一般都具有此功能.

 

执行音频获取
从设备获取音频比回放音频或视频要复杂一点,但是也还算简单:


创建一个android.media.MediaRecorder的新实例.
使用MediaRecorder.setAudioSource()设置音频源,一般要使用MediaRecorder.AudioSource.MIC.
使用MediaRecorder.setOutputFormat()设置输出文件的格式.
使用MediaRecorder.setOutputFile()设置输出文件的名字.
使用MediaRecorder.setAudioEncoder()设置音频编码.
调用MediaRecorder 实例的MediaRecorder.prepare().
MediaRecorder.start()开始获取音频.
调用MediaRecorder.stop().停止.
当你用完MediaRecorder实例后,调用MediaRecorder.release(),就会立即释放资源.

 


示例:录音并回放录音

下面的例子演示了如何设置,开始以及停止音频获取,以及回放录制的文件.

 

 

[java]
/*
 * 如果输出文件被写入外部存储,
 * 本应用需要具有写外部存储的权限, 
 * 还要具有录音的权限.这些权限必须
 * 在AndroidManifest.xml 文件中声明,像这样:
 *
 * <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
 * <uses-permission android:name="android.permission.RECORD_AUDIO" />
 *
 */ 
package com.android.audiorecordtest; 
 
import android.app.Activity; 
import android.widget.LinearLayout; 
import android.os.Bundle; 
import android.os.Environment; 
import android.view.ViewGroup; 
import android.widget.Button; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.content.Context; 
import android.util.Log; 
import android.media.MediaRecorder; 
import android.media.MediaPlayer; 
 
import java.io.IOException; 
 
 
public class AudioRecordTest extends Activity 

    private static final String LOG_TAG = "AudioRecordTest"; 
    private static String mFileName = null; 
   //录音按钮  
    private RecordButton mRecordButton = null; 
    private MediaRecorder mRecorder = null; 
   //回放按钮  
    private PlayButton   mPlayButton = null; 
    private MediaPlayer   mPlayer = null; 
 
   //当录音按钮被click时调用此方法,开始或停止录音  
    private void onRecord(boolean start) { 
        if (start) { 
            startRecording(); 
        } else { 
            stopRecording(); 
        } 
    } 
 
   //当播放按钮被click时调用此方法,开始或停止播放  
    private void onPlay(boolean start) { 
        if (start) { 
            startPlaying(); 
        } else { 
            stopPlaying(); 
        } 
    } 
 
    private void startPlaying() { 
        mPlayer = new MediaPlayer(); 
        try { 
    //设置要播放的文件  
            mPlayer.setDataSource(mFileName); 
            mPlayer.prepare(); 
    //播放之  
            mPlayer.start(); 
        } catch (IOException e) { 
            Log.e(LOG_TAG, "prepare() failed"); 
        } 
    } 
 
    //停止播放  
    private void stopPlaying() { 
        mPlayer.release(); 
        mPlayer = null; 
    } 
 
    private void startRecording() { 
        mRecorder = new MediaRecorder(); 
        //设置音源为Micphone  
        mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC); 
        //设置封装格式  
        mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP); 
        mRecorder.setOutputFile(mFileName); 
        //设置编码格式  
        mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB); 
 
        try { 
            mRecorder.prepare(); 
        } catch (IOException e) { 
            Log.e(LOG_TAG, "prepare() failed"); 
        } 
 
        mRecorder.start(); 
    } 
 
    private void stopRecording() { 
        mRecorder.stop(); 
        mRecorder.release(); 
        mRecorder = null; 
    } 
 
    //定义录音按钮  
    class RecordButton extends Button { 
        boolean mStartRecording = true; 
 
        OnClickListener clicker = new OnClickListener() { 
            public void onClick(View v) { 
                onRecord(mStartRecording); 
                if (mStartRecording) { 
                    setText("Stop recording"); 
                } else { 
                    setText("Start recording"); 
                } 
                mStartRecording = !mStartRecording; 
            } 
        }; 
 
        public RecordButton(Context ctx) { 
            super(ctx); 
            setText("Start recording"); 
            setOnClickListener(clicker); 
        } 
    } 
 
    //定义播放按钮  
    class PlayButton extends Button { 
        boolean mStartPlaying = true; 
 
        OnClickListener clicker = new OnClickListener() { 
            public void onClick(View v) { 
                onPlay(mStartPlaying); 
                if (mStartPlaying) { 
                    setText("Stop playing"); 
                } else { 
                    setText("Start playing"); 
                } 
                mStartPlaying = !mStartPlaying; 
            } 
        }; 
 
        public PlayButton(Context ctx) { 
            super(ctx); 
            setText("Start playing"); 
            setOnClickListener(clicker); 
        } 
    } 
 
    //构造方法  
    public AudioRecordTest() { 
        mFileName = Environment.getExternalStorageDirectory().getAbsolutePath(); 
        mFileName += "/audiorecordtest.3gp"; 
    } 
 
    @Override 
    public void onCreate(Bundle icicle) { 
        super.onCreate(icicle); 
        //构造界面  
        LinearLayout ll = new LinearLayout(this); 
        mRecordButton = new RecordButton(this); 
        ll.addView(mRecordButton, 
            new LinearLayout.LayoutParams( 
                ViewGroup.LayoutParams.WRAP_CONTENT, 
                ViewGroup.LayoutParams.WRAP_CONTENT, 
                0)); 
        mPlayButton = new PlayButton(this); 
        ll.addView(mPlayButton, 
            new LinearLayout.LayoutParams( 
                ViewGroup.LayoutParams.WRAP_CONTENT, 
                ViewGroup.LayoutParams.WRAP_CONTENT, 
                0)); 
        setContentView(ll); 
    } 
 
    @Override 
    public void onPause() { 
        super.onPause(); 
        //Activity暂停时释放录音和播放对象  
        if (mRecorder != null) { 
            mRecorder.release(); 
            mRecorder = null; 
        } www.2cto.com
 
        if (mPlayer != null) { 
            mPlayer.release(); 
            mPlayer = null; 
        } 
    } 


作者:nkmnkm

 

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