小编rua*_*mem的帖子

我正在使用 DialogFragment 并使用 Volley 将数据插入 mysql。数据已成功插入数据库，但之后总是崩溃。我总是在 logcat java.lang.NullPointerException 中收到此错误：尝试在空对象引用上调用虚拟方法 'java.lang.String android.content.Context.getPackageName()' 错误出现在我的 Toast 中。请帮忙

public class ExpensesLeisureDialog extends DialogFragment {
EditText name, amount, details;
String nameHolder, amountHolder, detailsHolder;
Boolean CheckEditText;
RequestQueue requestQueue;

HashMap<String,String> hashMap = new HashMap<>();
String finalResult;
HttpParse httpParse = new HttpParse();
String HttpURL = "http://10.0.2.2:63343/TheMoneyger/api/add-leisure.php";

@Override
public Dialog onCreateDialog (Bundle savedInstanceState) {
    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    LayoutInflater inflater = getActivity().getLayoutInflater();
    builder.setView(inflater.inflate(R.layout.fragment_add_expenses_dialog, null));
    requestQueue = Volley.newRequestQueue(getActivity().getApplicationContext());
    builder.setTitle("Add leisure expense")
            .setPositiveButton("Add", new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface …