MediaRecorder錄制音頻及代碼的抽取封裝
阿新 • • 發佈：2018-04-27
復雜 PE 音頻 reset environ star prot enable lse
1、背景
android提供了MediaRecorder類，通過MediaRecorder錄制音頻的過程很簡單，按步驟進行即可；在很多開發項目中，我們見到代碼的封裝很好；常常感覺這才是大牛寫出的代碼，其實我們也是可以寫出來的，今天就通過一個MediaRecorder錄制音頻的實例，進行代碼的抽取實現封裝；
2、MediaRecorder錄制音頻的步驟（來自瘋狂Androud講義）
1：創建MediaRecorder對象；
2：調用MediaRecorder對象的setAudioSource()方法設置聲音來源，一般傳入MediaRecorder.AudioSource.MIC參數，指定錄制來自麥克風的聲音；
3：調用MediaRecorder對象的setOutputFormat()設置所錄制的音頻文件的格式；
4：調用MediaRecorder對象的setAudioEncoder()、setAudioEncodingBitRate(int bitRate)、setAudioSamplingRate(int samplingRate)設置所錄制的聲音的編碼格式、編碼位率、采樣率等；這些參數將控制所錄制音頻的頻率，文件的大小；一般來說，聲音品質越好，文件越大；
5：調用MediaRedorder的setOutputFile(String path)方法，設置錄制的音頻文件的保存位置；
6：調用MediaRecorder的prepare()方法，準備錄制；
7：調用MdiaRecorder的start()方法，開始錄制；
8：錄制完成，調用MediaRecorder對象的stop(）方法停止錄制，並調用release(）方法釋放資源；
註意：上面的第3 和第4 兩個步驟，千萬不能搞反；否則程序將會拋出 IllegalStateException 異常；
3、MediaPlayer的狀態圖
我們參考MediaRecorder的狀態圖就可以明白MediaRecorder錄制音頻的步驟：
4、實例代碼：
沒抽取MediaRecorder之前的代碼：
1、布局文件
<LinearLayout 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:orientation="vertical"
tools:context=".MainActivity" >
<Button
android:id="@+id/openRecord"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Open Record"
android:textSize="20sp"
/>
<Button
android:id="@+id/closeRecord"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Close Record"
android:textSize="20sp"
/>
<Button
android:id="@+id/playSound"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Play Sound"
android:textSize="20sp"
/>
<Button
android:id="@+id/stopSound"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Stop Sound"
android:textSize="20sp"
/>
</LinearLayout>
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四個按鈕作用分別是：開始錄制音頻、停止錄制音頻、開始播放音頻、停止播放音頻
2、MainActivity代碼：
public class MyActivity extends Activity implements OnClickListener{
private Button bt_start;
private Button bt_stop;
private Button bt_play;
private Button bt_stopSound;
private MediaRecorder mRecorder;
private MediaPlayer mPlayer;
private File soundFile;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
}
private void initView() {
bt_start = (Button) this.findViewById(R.id.openRecord);
bt_stop = (Button) this.findViewById(R.id.closeRecord);
bt_play = (Button) this.findViewById(R.id.playSound);
bt_stopSound = (Button) this.findViewById(R.id.stopSound);
bt_start.setOnClickListener(this);
bt_stop.setOnClickListener(this);
bt_play.setOnClickListener(this);
bt_stopSound.setOnClickListener(this);
bt_play.setEnabled(false);
bt_stopSound.setEnabled(false);
mRecorder = new MediaRecorder();
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.openRecord:
startRecord();
break;
case R.id.closeRecord:
stopRecord();
break;
case R.id.playSound:
playSound();
break;
case R.id.stopSound:
stopSound();
break;
default:
break;
}
}
private void stopSound() {
if(mPlayer.isPlaying()){
mPlayer.stop();
mPlayer.release();
mPlayer = null;
}
}
private void stopRecord() {
if(null != mRecorder){
mRecorder.stop();
mRecorder.release();
bt_play.setEnabled(true);
bt_stopSound.setEnabled(true);
}
}
private void playSound() {
if(soundFile != null && soundFile.exists()){
try {
mPlayer = new MediaPlayer();
mPlayer.reset();
mPlayer.setDataSource(soundFile.getAbsolutePath());
mPlayer.prepare();
mPlayer.start();
} catch (Exception e) {
e.printStackTrace();
}
}
}
private void startRecord() {
if(!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
//Toast.makeText(MainActivity.this, "SD卡不存在，請插入SD卡！", Toast.LENGTH_LONG).show();
return;
}
try {
//創建保存錄制音頻的文件
soundFile = new File(Environment.getExternalStorageDirectory().getCanonicalFile(),"/sound.amr");
mRecorder.reset();
mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
mRecorder.setOutputFile(soundFile.getAbsolutePath());
mRecorder.prepare();
mRecorder.start();
} catch (Exception e) {
e.printStackTrace();
}
}
@Override
protected void onDestroy() {
if(null != mRecorder){
mRecorder.stop();
mRecorder.release();
mRecorder = null;
}
if(mPlayer != null){
mPlayer.stop();
mPlayer.release();
mPlayer = null;
}
super.onDestroy();
}
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在上面的MainActivity代碼中，我們可以看到雖然我們對代碼進行了很好的模塊化，但感覺如果我們把MediaRecorder 重新封裝，MainActivity的代碼量會更簡介；好了，現在我們就開始通過自定義一個MyMediaRecorder來封裝MediaRecorder，在MainActivity中我們只需通過MyMediaRecorder的封裝來調用MediaRecorder，可以簡化MainActivity中的代碼量；
3、MediaRecorder的封裝
public class MyMediaRecorder {
private MediaRecorder mRecorder;
private Context context;
public MyMediaRecorder(Context context){
mRecorder = new MediaRecorder();
this.context = context;
}
public void startRecord(File soundFile){
if(!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
Toast.makeText(context, "SD卡不存在，請插入SD卡！", Toast.LENGTH_LONG).show();
return;
}
try {
mRecorder.reset();
mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
mRecorder.setOutputFile(soundFile.getAbsolutePath());
mRecorder.prepare();
mRecorder.start();
} catch (Exception e) {
e.printStackTrace();
}
}
public void stopRecord(){
if(null != mRecorder){
mRecorder.stop();
mRecorder.release();
}
}
public void onDestroy(){
if(null != mRecorder){
mRecorder.stop();
mRecorder.release();
mRecorder = null;
}
}
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4、MediaPlayer的封裝
同樣我們也可以把MediaPlayer進行封裝：
public class MyMediaPlayer {
private MediaPlayer mPlayer;
public MyMediaPlayer(){
mPlayer = new MediaPlayer();
}
public void playSound(File soundFile){
try {
mPlayer.reset();
mPlayer.setDataSource(soundFile.getAbsolutePath());
mPlayer.prepare();
mPlayer.start();
} catch (Exception e) {
e.printStackTrace();
}
}
public void stopSound(){
if(mPlayer.isPlaying()){
mPlayer.stop();
mPlayer.release();
mPlayer = null;
}
}
public void onDestroy(){
if(mPlayer != null){
mPlayer.stop();
mPlayer.release();
mPlayer = null;
}
}
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5、封裝之後的MainActivity 代碼：
public class MyActivity02 extends Activity implements OnClickListener{
private Button bt_start;
private Button bt_stop;
private Button bt_play;
private Button bt_stopSound;
private MyMediaRecorder myMediaRecorder;
private MyMediaPlayer myMediaPlayer;
private File soundFile;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
}
private void initView() {
bt_start = (Button) this.findViewById(R.id.openRecord);
bt_stop = (Button) this.findViewById(R.id.closeRecord);
bt_play = (Button) this.findViewById(R.id.playSound);
bt_stopSound = (Button) this.findViewById(R.id.stopSound);
bt_start.setOnClickListener(this);
bt_stop.setOnClickListener(this);
bt_play.setOnClickListener(this);
bt_stopSound.setOnClickListener(this);
bt_play.setEnabled(false);
bt_stopSound.setEnabled(false);
//myMediaRecorder = new MyMediaRecorder(MainActivity.this);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.openRecord:
startRecord();
break;
case R.id.closeRecord:
stopRecord();
break;
case R.id.playSound:
playSound();
break;
case R.id.stopSound:
stopSound();
break;
default:
break;
}
}
public void stopSound() {
myMediaPlayer.stopSound();
}
public void playSound() {
if(soundFile != null && soundFile.exists()){
myMediaPlayer = new MyMediaPlayer();
myMediaPlayer.playSound(soundFile);
}
}
public void stopRecord() {
myMediaRecorder.stopRecord();
bt_play.setEnabled(true);
bt_stopSound.setEnabled(true);
}
public void startRecord() {
try {
soundFile = new File(Environment.getExternalStorageDirectory().getCanonicalFile(),"/sound.amr");
if(soundFile != null && soundFile.exists()){
myMediaRecorder.startRecord(soundFile);
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public void onDestroy() {
myMediaRecorder.onDestroy();
myMediaPlayer.onDestroy();
}
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現在，我們在MainActivity中只需要通過封裝好的MyMediaRecorder、MyMediaPlayer可以實現音頻的錄制；復雜的代碼都被我們封裝起來了，所以在我們的MainActivity中，代碼看上去更精煉；
現在我們看一下我們的MainActivity 還能更進一步封裝嗎？
其實代碼的封裝就是把有共性的給抽取出來，放到另一個類中；現在我們可以看到在我們的MainActivity中，各種視圖控件看上去占據了大部分代碼量，很繁瑣；由於視圖控件是一個界面，主要是與用戶進行交互的；看到他們的共性點，所以我們也是可以進行抽取的；
6、MainActivity的進一步抽取視圖控件
我把所有在MainActivity中出現的視圖控件，去不都抽取到MyManager中：
public class MyManager implements OnClickListener{
private Button bt_start;
private Button bt_stop;
private Button bt_play;
private Button bt_stopSound;
private MyMediaRecorder myMediaRecorder;
private MyMediaPlayer myMediaPlayer;
private File soundFile;
private MainActivity context;
public MyManager(Context context){
this.context = (MainActivity) context;
}
public void initView(){
bt_start = (Button) context.findViewById(R.id.openRecord);
bt_stop = (Button) context.findViewById(R.id.closeRecord);
bt_play = (Button) context.findViewById(R.id.playSound);
bt_stopSound = (Button) context.findViewById(R.id.stopSound);
bt_start.setOnClickListener(this);
bt_stop.setOnClickListener(this);
bt_play.setOnClickListener(this);
bt_stopSound.setOnClickListener(this);
bt_play.setEnabled(false);
bt_stopSound.setEnabled(false);
myMediaRecorder = new MyMediaRecorder(context);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.openRecord:
startRecord();
break;
case R.id.closeRecord:
stopRecord();
break;
case R.id.playSound:
playSound();
break;
case R.id.stopSound:
stopSound();
break;
default:
break;
}
}
public void stopSound() {
myMediaPlayer.stopSound();
}
public void playSound() {
if(soundFile != null && soundFile.exists()){
mhuachengj1980.comyMediaPlayer = new MyMediaPlayer();
myMediaPlayer.playSound(soundFile);
}
}
public vo078881.cnid stopRecord() {
myMediaRecorder.stopRecord();
bt_play.setEnabled(true);
bt_sto2636666.cnpSound.setEnabled(true);
}
public void startRecord() {
try {
soundFile = new File(Environment.getExternalStorageDirectory().getCanonicalFile(),"/sound.amr");
if(soundFile != null && soundFile.exists()){
myMediaRecorder.startRecord(soundFile);
}
} catch (IOException e) {
//mhylpt.com TODO Auto-generated catch block
e.printStackTrace();
}
}
public void onDestroy() {
myMediaRecorder.onDestroy();
myMediaPlayer.onDestroy();
}
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現在讓我們再看一下MainActivity 的代碼：
public class MainActivity extends Activity {
private MyManager manager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
}
private void initView() {
manager = new MyManager(MainActivity.this);
manager.initView();
}
@Override
protected void onDestroy() {
manager.onDestroy();
}
}
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是不是很驚訝，簡簡單單的4行代碼；對！！！這就是抽取、封裝的重要性，它能把我們的代碼進行提煉，讓代碼更精煉，更方便閱讀；
MediaRecorder錄制音頻及代碼的抽取封裝