To do this, you need to add the classes-full-debug.jar user library (from the aosp or cm assembly) BEFORE android.jar (there is a panel in the build path to sort the banners) or StorageManager will not allow registerListener() You will also need android.permission.MOUNT_UNMOUNT_FILESYSTEMS
package xyz; import android.app.Activity; import android.content.Context; import android.os.Bundle; import android.os.Environment; import android.os.IBinder; import android.os.RemoteException; import android.os.storage.IMountService; import android.os.storage.StorageEventListener; import android.os.storage.StorageManager; import android.os.ServiceManager; import android.widget.TextView; public class MyActivity extends Activity { private static final String MOUNTPOINT = "/mnt/sdcard"; private IMountService mMountService; private StorageManager mStorageManager; private TextView mText; private final StorageEventListener mStorageListener = new StorageEventListener() { @Override public void onStorageStateChanged(String path, String oldState, String newState) { String text = mText.getText() + "\n"; text += "state changed notification that " + path + " changed state from " + oldState + " to " + newState; mText.setText(text); } }; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mText = (TextView) findViewById(R.id.textView); if (mMountService == null) { IBinder service = ServiceManager.getService("mount"); mMountService = IMountService.Stub.asInterface(service); } if (mStorageManager == null) { mStorageManager = (StorageManager) getSystemService(Context.STORAGE_SERVICE); mStorageManager.registerListener(mStorageListener); } try { String state = mMountService.getVolumeState(MOUNTPOINT); mText.setText("Media state " + state); if (state.equals(Environment.MEDIA_MOUNTED)) mMountService.unmountVolume(MOUNTPOINT, false); else if (state.equals(Environment.MEDIA_UNMOUNTED)) mMountService.mountVolume(MOUNTPOINT); } catch (RemoteException e) { e.printStackTrace(); } } @Override protected void onDestroy() { if (mStorageManager != null && mStorageListener != null) mStorageManager.unregisterListener(mStorageListener); super.onDestroy(); } }