在下面的代码中，我的audioRecord对象未初始化。我尝试将其移至onCreate方法并使其成为全局方法。我已记录状态，并返回值1，这意味着可以使用。调试器表示正在对未初始化的对象调用startRecording。它也说无法获得音频源。
为什么我会收到这些错误？
package com.tecmark;
import java.io.BufferedOutputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import android.app.Activity;
import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.View;
import android.widget.TextView;
public class recorder extends Activity {
private Thread thread;
private boolean isRecording;
private AudioRecord recorder;
private FileOutputStream os;
private BufferedOutputStream bos;
private DataOutputStream dos;
private TextView text;
private int audioSource = MediaRecorder.AudioSource.MIC;
private int sampleRate = 22050;
private int channel = AudioFormat.CHANNEL_CONFIGURATION_MONO;
private int encoding = AudioFormat.ENCODING_PCM_16BIT;
private int result = 0;
private int bufferSize;
private byte[] buffer;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Log.v("onCreate", "layout set, about to init audiorec obj");
text = (TextView)findViewById(R.id.TextView01);
bufferSize = AudioRecord.getMinBufferSize(sampleRate,channel,encoding);
buffer = new byte[bufferSize];
recorder = new AudioRecord(audioSource, sampleRate,channel,encoding,
AudioRecord.getMinBufferSize(sampleRate, channel,encoding));
Log.i("recorder obj state",""+recorder.getRecordingState());
}
public void onClickPlay(View v){
}
public void record(){
Log.i("inside record method", "******");
File path = Environment.getExternalStorageDirectory();
Log.v("file path", ""+path.getAbsolutePath());
File file = new File(path, "test.wav");
if(file.exists()){
file.delete();
}
path.mkdirs();
Log.v("file path", ""+file.getAbsolutePath());
try {
os = new FileOutputStream(file);
bos = new BufferedOutputStream(os);
dos = new DataOutputStream(bos);
} catch (Exception e1) {
e1.printStackTrace();
}
int bufferSize = AudioRecord.getMinBufferSize(sampleRate,channel,encoding);
byte[] buffer = new byte[bufferSize];
recorder.startRecording();
isRecording = true;
try{
while (isRecording){
result = recorder.read(buffer, 0, bufferSize);
for(int a=0; a<result;a++){
dos.write(buffer[a]);
if(!isRecording){
recorder.stop();
break;
}
}
}
dos.flush();
dos.close();
}catch(Exception e){
e.printStackTrace();
}
}// end of record method
public void onClickStop(View v){
Log.v("onClickStop", "stop clicked");
isRecording=false;
}
public void onClickReverse(View v){
Log.v("onClickReverse", "reverse clicked");
}
public void onClickRecord(View v){
Log.v("onClickRecourd", "record clicked, thread gona start");
text.setText("recording");
thread = new Thread(new Runnable() {
public void run() {
isRecording = true;
record();
}
});
thread.start();
isRecording = false;
}
}//end of class
logcat的
01-30 15:23:16.724: ERROR/AudioRecord(12817): Could not get audio input for record source 1 01-30 15:23:16.729:
ERROR/AudioRecord-JNI(12817): Error creating AudioRecord instance: initialization check failed. 01-30 15:23:16.729:
ERROR/AudioRecord-Java(12817): [ android.media.AudioRecord ] Error code
-20 when initializing native AudioRecord object. 01-30 15:23:16.729: INFO/recorder obj state(12817): 1 01-30 15:23:16.729:
WARN/dalvikvm(12817): threadid=13: thread exiting with uncaught exception (group=0x4001b180) 01-30 15:23:16.729:
ERROR/AndroidRuntime(12817): Uncaught handler: thread Thread-7 exiting due to uncaught exception 01-30 15:23:16.739:
ERROR/AndroidRuntime(12817): java.lang.IllegalStateException: startRecording() called on an uninitialized AudioRecord. 01-30 15:23:16.739:
ERROR/AndroidRuntime(12817): at android.media.AudioRecord.startRecording(AudioRecord.java:495) 01-30 15:23:16.739:
ERROR/AndroidRuntime(12817): at com.tecmark.recorder.record(recorder.java:114) 01-30 15:23:16.739:
ERROR/AndroidRuntime(12817): at com.tecmark.recorder$1.run(recorder.java:175) 01-30 15:23:16.739:
ERROR/AndroidRuntime(12817): at java.lang.Thread.run(Thread.java:1096)
答案 0 :(得分：92)
使用AudioRecord的技巧是每个设备可能有不同的初始化设置，因此您必须创建一个循环所有可能的比特率，编码等组合的方法。
private static int[] mSampleRates = new int[] { 8000, 11025, 22050, 44100 };
public AudioRecord findAudioRecord() {
for (int rate : mSampleRates) {
for (short audioFormat : new short[] { AudioFormat.ENCODING_PCM_8BIT, AudioFormat.ENCODING_PCM_16BIT }) {
for (short channelConfig : new short[] { AudioFormat.CHANNEL_IN_MONO, AudioFormat.CHANNEL_IN_STEREO }) {
try {
Log.d(C.TAG, "Attempting rate " + rate + "Hz, bits: " + audioFormat + ", channel: "
+ channelConfig);
int bufferSize = AudioRecord.getMinBufferSize(rate, channelConfig, audioFormat);
if (bufferSize != AudioRecord.ERROR_BAD_VALUE) {
// check if we can instantiate and have a success
AudioRecord recorder = new AudioRecord(AudioSource.DEFAULT, rate, channelConfig, audioFormat, bufferSize);
if (recorder.getState() == AudioRecord.STATE_INITIALIZED)
return recorder;
}
} catch (Exception e) {
Log.e(C.TAG, rate + "Exception, keep trying.",e);
}
}
}
}
return null;
}
AudioRecord recorder = findAudioRecord();
recorder.release();
答案 1 :(得分：91)
我有同样的问题，它是通过放
来解决的<uses-permission android:name="android.permission.RECORD_AUDIO"></uses-permission>
进入清单。
自Lollipop以来，您还需要具体询问用户每个权限。因为他们可能已经撤销了他们。确保授予权限。
答案 2 :(得分：9)
根据javadocs，所有设备都保证支持这种格式（用于录制）：
44100，AudioFormat.CHANNEL_IN_MONO，AudioFormat.ENCODING_PCM_16BIT。
更改为CHANNEL_OUT_MONO进行播放。
答案 3 :(得分：4)
现在，使用棒棒糖，您需要专门询问用户是否有权限。确保授予权限。
答案 4 :(得分：4)
即使在完成上述所有步骤后，我也遇到了同样的问题，对我来说有用的是我的操作系统是棉花糖，我不得不要求获得许可。
答案 5 :(得分：3)
初始化少数AudioRecord对象的问题可以通过在创建下一个对象之前使用audioRecord.release();来修复...
更多信息：Android AudioRecord - Won't Initialize 2nd time
答案 6 :(得分：2)
刚遇到同样的问题。 解决方案是重启设备。在播放代码时，我没有发布AudioRecord对象，这显然导致音频设备卡住了。 为了测试音频设备是否有效，我从Google Play下载了Audalyzer。
答案 7 :(得分：2)
如果您的手机系统是Android M或更高版本，则可能需要在Android M中应用录制音频权限。http://developer.android.com/guide/topics/security/permissions.html
答案 8 :(得分：2)
在我的情况下，我必须手动允许android 7中的麦克风权限，正如肖恩珠所评论的那样。
答案 9 :(得分：1)
我注意到当我运行的avd上的SDCard变满时，AudioRecord构造函数返回null。您是否尝试过清除SD卡？
答案 10 :(得分：0)
我认为这与线程有关，不知道你已经暂停了主要活动，并且在你停止录制后仍然试图录制。
我通过更改onResume（）和onPause（）方法来解决它，以修改isRecording boolean。
public void onResume() {
...
isRecording = true;
}
public void onPause() {
...
isRecording = false;
}
然后在你的主题中，使用if-statements检查isRecording：{/ 1>} startRecording()和stop()。
if(isRecording)
recorder.startRecording();
...
if(isRecording)
recorder.stop(); // which you've done
答案 11 :(得分：0)
我重写了@DustinB对任何使用Xamarin Android AudioRecord和C＃的人的回答。
int[] sampleRates = new int[] { 44100, 22050, 11025, 8000 };
Encoding[] encodings = new Encoding[] { Encoding.Pcm8bit, Encoding.Pcm16bit };
ChannelIn[] channelConfigs = new ChannelIn[]{ ChannelIn.Mono, ChannelIn.Stereo };
//Not all of the formats are supported on each device
foreach (int sampleRate in sampleRates)
{
foreach (Encoding encoding in encodings)
{
foreach (ChannelIn channelConfig in channelConfigs)
{
try
{
Console.WriteLine("Attempting rate " + sampleRate + "Hz, bits: " + encoding + ", channel: " + channelConfig);
int bufferSize = AudioRecord.GetMinBufferSize(sampleRate, channelConfig, encoding);
if (bufferSize > 0)
{
// check if we can instantiate and have a success
AudioRecord recorder = new AudioRecord(AudioSource.Mic, sampleRate, channelConfig, encoding, bufferSize);
if (recorder.State == State.Initialized)
{
mBufferSize = bufferSize;
mSampleRate = sampleRate;
mChannelConfig = channelConfig;
mEncoding = encoding;
recorder.Release();
recorder = null;
return true;
}
}
}
catch (Exception ex)
{
Console.WriteLine(sampleRate + "Exception, keep trying." + ex.Message);
}
}
}
}