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Android 音訊錄製(Audio Capture)

本文是 Android Developer 上官方文件的個人翻譯,囿於作者英文水平,可能比較粗糙,原文如下:

Android 多媒體框架包含了對錄製和編碼為多種音訊格式的支援,因此你可以很簡單地將音訊整合到自己的應用中。如果裝置支援的話,你可以使用 MediaRecorder APIs 來錄製音訊。

本文件向你展示如何編寫一個應用,可以從裝置的麥克風錄製音訊、儲存並播放。

注意:Android 模擬器沒有錄製音訊的能力,真機一般都會有這種功能。

執行音訊錄製(Performing Audio Capture)

音訊錄製相對音訊和視訊的播放來說稍微有一點複雜,但仍然相當簡單:

示例:錄製音訊並播放錄製的音訊

下面的示例類演示瞭如何建立、開始和停止音訊錄製,最後播放錄製的音訊檔案。

/*
 * The application needs to have the permission to write to external storage
 * if the output file is written to the external storage, and also the
 * permission to record audio. These permissions must be set in the
 * application's AndroidManifest.xml file, with something like:
 *
 * <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; private RecordButton mRecordButton = null; private MediaRecorder mRecorder = null; private PlayButton mPlayButton = null; private MediaPlayer mPlayer = null; private void onRecord(boolean start) { if (start) { startRecording(); } else { stopRecording(); } } private void onPlay(boolean start) { if (start) { startPlaying(); } else { stopPlaying(); } } private void startPlaying() { mPlayer = new MediaPlayer(); try { mPlayer.setDataSource(mFileName); mPlayer.prepare(); mPlayer.start(); } catch (IOException e) { Log.e(LOG_TAG, "prepare() failed"); } } private void stopPlaying() { mPlayer.release(); mPlayer = null; } private void startRecording() { mRecorder = new MediaRecorder(); mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC); mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP); mRecorder.setOutputFile(mFileName); 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; } 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); } } 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); } } public AudioRecordTest() { mFileName = Environment.getExternalStorageDirectory().getAbsolutePath(); mFileName += "/audiorecordtest.3gp"; } @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); 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(); if (mRecorder != null) { mRecorder.release(); mRecorder = null; } if (mPlayer != null) { mPlayer.release(); mPlayer = null; } } }