我正在尝试使用MediaRecorder在我的一个活动中录制音频。部分代码如下所示。
File file = new File(AppConstants.MSGS_DIR, filename);
MediaRecorder recorder = new MediaRecorder();
recorder.setAudioSource(AudioSource.MIC);
recorder.setOutputFormat(OutputFormat.THREE_GPP);
recorder.setAudioEncoder(AudioEncoder.AMR_WB);
recorder.setOutputFile(file.getAbsolutePath());
try {
recorder.prepare();
recorder.start();
} catch (IOException e) {
System.out.println("Exception: " + e.getMessage());
}
我在清单文件中提供了以下权限。
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_SETTINGS" />
但是在 recorder.start（）这一行我得到了运行时异常。 Logcat显示以下错误消息。
09-23 15:47:54.462: E/AndroidRuntime(8697): FATAL EXCEPTION: main
09-23 15:47:54.462: E/AndroidRuntime(8697): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mypackage/com.mypackage.RecordingActivity}: java.lang.RuntimeException: start failed.
09-23 15:47:54.462: E/AndroidRuntime(8697): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2250)
09-23 15:47:54.462: E/AndroidRuntime(8697): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2300)
09-23 15:47:54.462: E/AndroidRuntime(8697): at android.app.ActivityThread.access$600(ActivityThread.java:144)
09-23 15:47:54.462: E/AndroidRuntime(8697): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1295)
09-23 15:47:54.462: E/AndroidRuntime(8697): at android.os.Handler.dispatchMessage(Handler.java:99)
09-23 15:47:54.462: E/AndroidRuntime(8697): at android.os.Looper.loop(Looper.java:150)
09-23 15:47:54.462: E/AndroidRuntime(8697): at android.app.ActivityThread.main(ActivityThread.java:5162)
09-23 15:47:54.462: E/AndroidRuntime(8697): at java.lang.reflect.Method.invokeNative(Native Method)
09-23 15:47:54.462: E/AndroidRuntime(8697): at java.lang.reflect.Method.invoke(Method.java:525)
09-23 15:47:54.462: E/AndroidRuntime(8697): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:744)
09-23 15:47:54.462: E/AndroidRuntime(8697): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
09-23 15:47:54.462: E/AndroidRuntime(8697): at dalvik.system.NativeStart.main(Native Method)
09-23 15:47:54.462: E/AndroidRuntime(8697): Caused by: java.lang.RuntimeException: start failed.
09-23 15:47:54.462: E/AndroidRuntime(8697): at android.media.MediaRecorder.start(Native Method)
09-23 15:47:54.462: E/AndroidRuntime(8697): at com.mypackage.RecordingActivity.startRecording(RecordingActivity.java:169)
09-23 15:47:54.462: E/AndroidRuntime(8697): at com.mypackage.RecordingActivity.onCreate(RecordingActivity.java:107)
09-23 15:47:54.462: E/AndroidRuntime(8697): at android.app.Activity.performCreate(Activity.java:5288)
09-23 15:47:54.462: E/AndroidRuntime(8697): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
09-23 15:47:54.462: E/AndroidRuntime(8697): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2214)
尝试了与stackoverflow中的错误相对应的问题，但无法从中得出有效的答案。请检查一下，并帮助我解决代码中出错的问题。
FYI＆GT;这段代码仅在特定设备中失败。我错过了任何其他权限吗？
答案 0 :(得分：3)
很少有设备不支持，因为它们不支持3GP格式以及AudioEncoder.AMR_WB编码。点击here查看支持的格式。
请使用以下代码，以支持最大数量的设备。
recorder.setOutputFormat(OutputFormat.MPEG_4);
recorder.setAudioEncoder(AudioEncoder.AAC);
答案 1 :(得分：-1)
如果您使用的是Api 23，则首先获得许可，然后开始录制
private boolean checkAndRequestPermissions() {
int permissionSendMessage = ContextCompat.checkSelfPermission(this,
Manifest.permission.WRITE_EXTERNAL_STORAGE);
int locationPermission = ContextCompat.checkSelfPermission(this, Manifest.permission.RECORD_AUDIO);
List<String> listPermissionsNeeded = new ArrayList<>();
if (locationPermission != PackageManager.PERMISSION_GRANTED) {
listPermissionsNeeded.add(Manifest.permission.RECORD_AUDIO);
}
if (permissionSendMessage != PackageManager.PERMISSION_GRANTED) {
listPermissionsNeeded.add(Manifest.permission.WRITE_EXTERNAL_STORAGE);
}
if (!listPermissionsNeeded.isEmpty()) {
ActivityCompat.requestPermissions(this, listPermissionsNeeded.toArray(new String[listPermissionsNeeded.size()]),REQUEST_ID_MULTIPLE_PERMISSIONS);
return false;
}
return true;
}
@Override
public void onRequestPermissionsResult(int requestCode,
String permissions[], int[] grantResults) {
Log.d("TAG", "Permission callback called-------");
switch (requestCode) {
case REQUEST_ID_MULTIPLE_PERMISSIONS: {
Map<String, Integer> perms = new HashMap<>();
// Initialize the map with both permissions
perms.put(Manifest.permission.WRITE_EXTERNAL_STORAGE, PackageManager.PERMISSION_GRANTED);
perms.put(Manifest.permission.RECORD_AUDIO, PackageManager.PERMISSION_GRANTED);
// Fill with actual results from user
if (grantResults.length > 0) {
for (int i = 0; i < permissions.length; i++)
perms.put(permissions[i], grantResults[i]);
// Check for both permissions
if (perms.get(Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED
&& perms.get(Manifest.permission.RECORD_AUDIO) == PackageManager.PERMISSION_GRANTED) {
Log.d("TAG", "sms & location services permission granted");
// process the normal flow
pager = (ViewPager) findViewById(R.id.pager);
pager.setAdapter(new MyAdapter(getSupportFragmentManager()));
tabs = (PagerSlidingTabStrip) findViewById(R.id.tabs);
tabs.setViewPager(pager);
//else any one or both the permissions are not granted
} else {
Log.d("TAG", "Some permissions are not granted ask again ");
//permission is denied (this is the first time, when "never ask again" is not checked) so ask again explaining the usage of permission
// // shouldShowRequestPermissionRationale will return true
//show the dialog or snackbar saying its necessary and try again otherwise proceed with setup.
if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) ||
ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.RECORD_AUDIO)) {
showDialogOK("SMS and Location Services Permission required for this app",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
switch (which) {
case DialogInterface.BUTTON_POSITIVE:
checkAndRequestPermissions();
break;
case DialogInterface.BUTTON_NEGATIVE:
// proceed with logic by disabling the related features or quit the app.
break;
}
}
});
}
//permission is denied (and never ask again is checked)
//shouldShowRequestPermissionRationale will return false
else {
Toast.makeText(this, "Go to settings and enable permissions", Toast.LENGTH_LONG)
.show();
// //proceed with logic by disabling the related features or quit the app.
}
}
}
}
}
}
private void showDialogOK(String message, DialogInterface.OnClickListener okListener) {
new AlertDialog.Builder(this)
.setMessage(message)
.setPositiveButton("OK", okListener)
.setNegativeButton("Cancel", okListener)
.create()
.show();
}