为什么我的Audio_Recorder可以在Samsung上运行而不能在Nexus手机上运行？

Question

I'm trying to record audio and save it in a new folder. In Samsung devices, it is working, but in a Nexus phone it gives some errors. I get two errors: One is in the first line of my public class & the second one is in the startRecording() line. Here is my code:

MainActivity.java:

public class MainActivity extends AppCompatActivity {

    @Override
    public void onCreate(Bundle savedInstanceState) {    
        super.onCreate(savedInstanceState);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_main);

         mRecordBtn.setOnTouchListener(new View.OnTouchListener()
         {
            @Override
            public boolean onTouch(View view, MotionEvent motionEvent)
            {
                if (motionEvent.getAction() == MotionEvent.ACTION_DOWN) {

                    startRecording();       //<<<<<<<<<<<<<<<<HERE AN ERROR
                    mRecordLabel.setText("GRAVANDO");
                    adp.notifyDataSetChanged();


                } else if (motionEvent.getAction() == MotionEvent.ACTION_UP) {

                    stopRecording();
                    mRecordLabel.setText("GRAVADO");

                    lv.setAdapter(adp);
                    adp.notifyDataSetChanged();
                }

                return false;
            }
         });
         ...
    }

    private void startRecording()
    {

    Long tsLong = System.currentTimeMillis()/1000;
    String ts = tsLong.toString();
    mRecorder = new MediaRecorder();
    mRecorder.reset();
    mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    mRecorder.setOutputFormat(MediaRecorder.OutputFormat.DEFAULT);
    mRecorder.setOutputFile(mFileName);
    mRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
    int permissionCheck = ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE);
    String sep = File.separator; // Use this instead of hardcoding the "/"
    String newFolder = "FolderName";
    String extStorageDirectory = Environment.getExternalStorageDirectory().toString();
    File myNewFolder = new File(extStorageDirectory + sep + newFolder);
    //myNewFolder.mkdir();
    myNewFolder.mkdirs();

    mFileName = Environment.getExternalStorageDirectory().toString()
            + sep + newFolder + sep + "Record."+ts+".mp3";
    ...
    }
...
}

Here is the errors from the logcat:

java.lang.RuntimeException: setAudioSource failed.
at org.usr.usr.musicplayer.MainActivity.startRecording(MainActivity.java:222) =   mRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
at org.usr.usr.musicplayer.MainActivity.access$000(MainActivity.java:72) = public class MainActivity extends AppCompatActivity { 
at org.usr.usr.musicplayer.MainActivity$3.onTouch(MainActivity.java:196) = startRecording();

Manifest

 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="org.usr.usr.musicplayer">

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.CHANGE_CONFIGURATION" />
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS" />


<application
    android:allowBackup="true"
    android:icon="@drawable/llama10"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/PlayerTheme">
    <activity android:name=".MainActivity"
        android:launchMode="singleTop"
        android:screenOrientation="portrait">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name=".Player"
        android:launchMode="singleTop"
        android:screenOrientation="portrait">
    </activity>
</application>

Answer 1

It is not device issue. It is an API Version issue. You must find out which API Version is crashing, then you should be able to narrow out your problem with little research.

Answer 2

Given you are targetting api 24 and lets say you are supporting API 16 and greater, you will have to request permission at runtime for READ_EXTERNAL_STORAGE, WRITE_EXTERNAL_STORAGE (I think this last one covers both read and write but I am listing both to be on the safe side), and RECORD_AUDIO as these are considered dangerous permissions.

You have todo this before starting to record and the app has to handle if the user does't provede the permissions when the app asks for them, or revokes them after having provided them some time before.

It is rather complex to implement it involves:

1. Checking if you have permission grantes.
2. If not, check if the user has stated not to be asked again
3. Check if you should provide some explanation about why the app needs those permissions.

If you find Android Dox are not helping checkout this tutorial Android 6.0 Runtime Permissions a CommonsWare Code Lab