对于API＆lt; android mediaRecorder.setAudioSource失败了23

Question

我正在尝试为分贝计应用录制声音。我的AndroidManifest具有以下权限：

    <uses-permission android:name="android.permission.RECORD_AUDIO" />

当我的记录器在Noise.java（记录发生的地方）

开始时，我也会检查它

    public void startRecorder() {
        if (ActivityCompat.checkSelfPermission(Noise.this, Manifest.permission.RECORD_AUDIO) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(Noise.this, new String[]{Manifest.permission.RECORD_AUDIO}, RECORD_AUDIO);
        }  else {
             if (Recorder == null) {
                 Recorder = new MediaRecorder();
                 Recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
                 Recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
                 Recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
                 Recorder.setOutputFile("/dev/null");
                try {
                    Recorder.prepare();
                } catch (java.io.IOException ioe) {
                    android.util.Log.e(LOG_TAG, "IOException: " + android.util.Log.getStackTraceString(ioe));
                } catch (java.lang.SecurityException e) {
                    android.util.Log.e(LOG_TAG, "SecurityException: " + android.util.Log.getStackTraceString(e));
                }
                try {
                    Recorder.start();
                } catch (java.lang.SecurityException e) {
                    android.util.Log.e(LOG_TAG, "SecurityException: " + android.util.Log.getStackTraceString(e));
                }
            }
        }
    }

它完美适用于API＆gt; 23，但在较老的那些我得到了

    java.lang.RuntimeException: Unable to resume activity {com.mycompany.audiorecorder/com.mycompany.audiorecorder.Noise}: java.lang.RuntimeException: setAudioSource failed.
                                                                         at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3645)
                                                                         at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:3685)
                                                                         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2898)
                                                                         at android.app.ActivityThread.-wrap11(Unknown Source:0)
                                                                         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1593)
                                                                         at android.os.Handler.dispatchMessage(Handler.java:105)
                                                                         at android.os.Looper.loop(Looper.java:164)
                                                                         at android.app.ActivityThread.main(ActivityThread.java:6541)
                                                                         at java.lang.reflect.Method.invoke(Native Method)
                                                                         at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
                                                                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
                                                                      Caused by: java.lang.RuntimeException: setAudioSource failed.
                                                                         at android.media.MediaRecorder.setAudioSource(Native Method)
                                                                         at com.mycompany.audiorecorder.Noise.startRecorder(Noise.java:111)
                                                                         at com.mycompany.audiorecorder.Noise.onResume(Noise.java:92)
                                                                         at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1354)
                                                                         at android.app.Activity.performResume(Activity.java:7079)
                                                                         at android.app.ActivityThread.performResumeActivity(ActivityThread.java:3620)

我选中了“设置＆gt;应用＆gt; MyApp＆gt;权限”，并启用了麦克风权限。

我该怎么做才能解决问题？