小吃店中的空对象引用

Question

我有一个片段视图，检查互联网连接代码。在showSnack函数的else部分中获取错误如下。

错误：尝试调用虚方法＆＃39; android.content.Context android.view.ViewGroup.getContext（）＆＃39;在空对象引用上

以下是我的代码

public class LatestNews extends Fragment implements SwipeRefreshLayout.OnRefreshListener, ConnectivityReceiver.ConnectivityReceiverListener {
//declare variables
 @Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View v = inflater.inflate(R.layout.list_view,container,false);
    // Manually checking internet connection
    checkConnection();
    return v;
});

private void checkConnection() {
    boolean isConnected = ConnectivityReceiver.isConnected();
    showSnack(isConnected);
}

private void showSnack(boolean isConnected) {
    String message;
    int color;
    if (isConnected) {
        new DownloadJSON().execute();
    } else {
        swipeRefreshLayout.setRefreshing(false);
        mProgressBar.setVisibility(View.GONE);
        message = "Sorry! Not connected to internet";
        color = Color.RED;
        Snackbar snackbar = Snackbar.make(getActivity().findViewById(R.id.fab), message, Snackbar.LENGTH_LONG);
        View sbView = snackbar.getView();
        TextView textView = (TextView) sbView.findViewById(android.support.design.R.id.snackbar_text);
        textView.setTextColor(color);
        snackbar.show();
    }
}
@Override
public void onNetworkConnectionChanged(boolean isConnected) {
    showSnack(isConnected);
}