我有问题。我目前正在开发一个应用程序，它只记录我的声音，而不是来自手机的声音。我读过＆＃34; MediaRecorder.AudioSource.VOICE_UPLINK ＆＃34;可以做这个任务。
这是我的java代码。
package com.khagendra.zip_it;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import java.io.IOException;
public class Settings extends Fragment {
Button start,stop;
boolean fingerDown = false;
private Thread thread;
private int lastLevel;
public Settings(){
}
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.settings_activity,container,false);
}
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
start = (Button) view.findViewById(R.id.bstart);
stop = (Button) view.findViewById(R.id.bstop);
stop.setEnabled(false);
final SoundMeter sm = new SoundMeter();
start.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Log.d("level","started");
sm.start();
sm.getAmplitude();
}
});
stop.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
v.setSelected(false);
start.setEnabled(true);
stop.setEnabled(false);
Log.d("level","stopped");
sm.stop();
}
});
}
public class SoundMeter {
private MediaRecorder mRecorder = null;
public void start() {
if (mRecorder == null) {
mRecorder = new MediaRecorder();
mRecorder.setAudioSource(MediaRecorder.AudioSource.VOICE_UPLINK);
mRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
mRecorder.setOutputFile("/dev/null");
try {
mRecorder.prepare();
} catch (IOException e) {
e.printStackTrace();
}
try {
mRecorder.start();
}catch (Throwable t){
t.printStackTrace();
Log.d("level_error",""+t);
}
}
}
public void stop() {
thread.interrupt();
thread = null;
if (mRecorder != null) {
mRecorder.stop();
mRecorder.release();
mRecorder = null;
}
}
public void getAmplitude() {
thread = new Thread(new Runnable() {
public void run() {
while(thread != null && !thread.isInterrupted()){
//Let's make the thread sleep for a the approximate sampling time
try{Thread.sleep(75);}catch(InterruptedException ie){ie.printStackTrace();}
//readAudioBuffer();//After this call we can get the last value assigned to the lastLevel variable
getActivity().runOnUiThread(new Runnable() {
@Override
public void run() {
if (mRecorder != null) {
lastLevel = mRecorder.getMaxAmplitude();
if(lastLevel>2000)
Log.d("level", "medium:" + lastLevel);
}
}
});
}
}
});
thread.start();
}
}
}
这是我的logcat输出：
06-17 18:52:37.994 12129-12129/com.khagendra.zip_it D/level﹕ started
06-17 18:52:38.034 12129-12129/com.khagendra.zip_it E/MediaRecorder﹕ start failed: -2147483648
06-17 18:52:38.054 12129-12129/com.khagendra.zip_it W/System.err﹕ java.lang.RuntimeException: start failed.
06-17 18:52:38.064 12129-12129/com.khagendra.zip_it W/System.err﹕ at android.media.MediaRecorder.start(Native Method)
06-17 18:52:38.064 12129-12129/com.khagendra.zip_it W/System.err﹕ at com.khagendra.zip_it.Settings$SoundMeter.start(Settings.java:103)
06-17 18:52:38.064 12129-12129/com.khagendra.zip_it W/System.err﹕ at com.khagendra.zip_it.Settings$1.onClick(Settings.java:69)
06-17 18:52:38.064 12129-12129/com.khagendra.zip_it W/System.err﹕ at android.view.View.performClick(View.java:4432)
06-17 18:52:38.064 12129-12129/com.khagendra.zip_it W/System.err﹕ at android.view.View$PerformClick.run(View.java:18338)
06-17 18:52:38.064 12129-12129/com.khagendra.zip_it W/System.err﹕ at android.os.Handler.handleCallback(Handler.java:725)
06-17 18:52:38.064 12129-12129/com.khagendra.zip_it W/System.err﹕ at android.os.Handler.dispatchMessage(Handler.java:92)
06-17 18:52:38.064 12129-12129/com.khagendra.zip_it W/System.err﹕ at android.os.Looper.loop(Looper.java:137)
06-17 18:52:38.064 12129-12129/com.khagendra.zip_it W/System.err﹕ at android.app.ActivityThread.main(ActivityThread.java:5283)
06-17 18:52:38.064 12129-12129/com.khagendra.zip_it W/System.err﹕ at java.lang.reflect.Method.invokeNative(Native Method)
06-17 18:52:38.074 12129-12129/com.khagendra.zip_it W/System.err﹕ at java.lang.reflect.Method.invoke(Method.java:511)
06-17 18:52:38.074 12129-12129/com.khagendra.zip_it W/System.err﹕ at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1102)
06-17 18:52:38.074 12129-12129/com.khagendra.zip_it W/System.err﹕ at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:869)
06-17 18:52:38.074 12129-12129/com.khagendra.zip_it W/System.err﹕ at dalvik.system.NativeStart.main(Native Method)
06-17 18:52:38.074 12129-12129/com.khagendra.zip_it D/level_error﹕ java.lang.RuntimeException: start failed.
我知道有人建议使用＆＃34; MediaRecorder.AudioSource.MIC ＆＃34;。所以，我试过了。它的工作正常，但我想＆＃34; VOICE_UPLINK ＆＃34;或＆＃34; VOICE_DOWNLINK ＆＃34;上班。 任何形式的帮助都将受到高度赞赏。
附加信息：我正在考虑在通话期间实施相同的操作，以便我只能录制我的声音。但是现在我想要这个工作。
答案 0 :(得分：1)
此功能需要权限CAPTURE_AUDIO_OUTPUT。但此权限仅保留给系统应用程序，不能由第三方应用程序使用。这意味着，只要您的应用程序不是系统应用程序，就无法使用它。使您的应用程序成为系统应用程序将需要一些复杂的东西和root设备/仅适用于root设备。
来自文档：
VOICE_DOWNLINK
从VOICE_DOWNLINK源捕获需要CAPTURE_AUDIO_OUTPUT权限。此权限保留供系统组件使用，不可用于第三方应用程序。
VOICE_UPLINK
从VOICE_UPLINK源捕获需要CAPTURE_AUDIO_OUTPUT权限。此权限保留供系统组件使用，不可用于第三方应用程序。