Not working context menu item in fragment

public class ThreeFragment extends Fragment {

public View ThreeFragmentView = null;
public static TextView internalMemoryInfo;
public static Button IntBtn;

public ThreeFragment() {
// Required empty public constructor
}

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}

@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
if (ThreeFragmentView == null) ThreeFragmentView = inflater.inflate(R.layout.fragment_three, container, false);
internalMemoryInfo = (TextView) ThreeFragmentView.findViewById(R.id.textViewInternalMemoryInfo);
IntBtn = (Button) ThreeFragmentView.findViewById(R.id.InternalBtn);
return ThreeFragmentView;
}

public static void showText(String text) {
internalMemoryInfo.setText(text);
}

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
registerForContextMenu(IntBtn);
}

@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
switch (v.getId()){
case R.id.InternalBtn:
menu.setHeaderTitle("Internal Memory Menu");
menu.add(0, ClearCacheMet, 0, "Clear Cache");
menu.add(0, Common, 0, "Go to Common Tab");
menu.add(0, ITEM_CANCEL, 0, "Cancel");
break;
}
}

@Override
public boolean onContextItemSelected(MenuItem item) {
switch (item.getItemId()) {
case ClearCacheMet:
ClearCache(); <-------This not working
break;
case Common:
tabLayout.getTabAt(0).select(); <-------This working
break;
case ITEM_CANCEL:
ins.closeContextMenu(); <-------This working
break;
}
return true;
}

public static boolean deleteDir(File dir){
if (dir != null && dir.isDirectory()) {
String[] children = dir.list();
for (int i = 0; i < children.length; i++) {
boolean success = deleteDir(new File(dir, children[i]));
if (!success) {
return false;
}
}
}
return dir.delete();
}

public static void ClearCache() {
File cache = ins.getCacheDir();
File appDir = new File(cache.getParent());
if (appDir.exists()) {
String[] children = appDir.list();
for (String s : children) {
if (!s.equals("lib")) {
deleteDir(new File(appDir, s));
}
}
}

try{
    /*if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
        ((ActivityManager) ins.getSystemService(Context.ACTIVITY_SERVICE)).clearApplicationUserData();
    } else {*/
        File externalcache = ins.getExternalCacheDir();
        File externalappDir = new File(externalcache.getParent());
        if (externalappDir.exists()) {
            String[] children = externalappDir.list();
            for (String s : children) {
                if (!s.equals("lib")) {
                    deleteDir(new File(externalappDir, s));
                }
            }
        } else {
            Log.d(TAG, "No externalappDir");
        }
    /*}*/
} catch (Exception e) {
    Log.d(TAG, "MainActivity in ClearCache");
}

}

I have fragment(ThreeFragment) with button(InternalBtn) that have a context menu. Context menu registered with registerForContextMenu(IntBtn); Menu item ClearCacheMet not working. I cannot see neither Toast.makeText().show(); nor Log.d(TAG, "ClearCache"); Common and ITEM_CANCEL items working. I cannot understand why? Please help me.
Toast.makeText(getActivity(), "Called !", Toast.LENGTH_SHORT).show(); not called in ClearCache() function. ClearCacheMet and Common were initialized in other fragment.

public class OneFragment extends Fragment {
public View OneFragmentView = null;
public static final int Common = 25;
public static final int ClearCacheMet = 50;