如何在Android Java中访问/ dev目录？

Question

I'm trying to communicate with Android directly via serial port (but not via USB!)

Need to access /dev directory. But can't.

(I'm using Android Studio.)

File dir2 = new File("/dev");
dir2.listFiles(); ---> this is null !

I can connect via adb shell and then see all files , but can't do it in my app.

File dir0 = new File("/");
dir0.listFiles();  ----> this works fine and list all files.

I granted permissions in android_manifest.xml :

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
<uses-permission android:name="android.permission.MOUNT_FORMAT_FILESYSTEMS"/>

Also my device is rooted, and I check/ask root permissions with:

Process root = Runtime.getRuntime().exec("su");
txPrint1.append("\n \n root GRANTED \n \n");

Still can't access /dev files. What to do?

Answer 1

Solved. I used different device and it worked.