对话框无法获取上下文

Question

我有一个对话框，当我首先调用它时一切正常，但是当我第二次调用时，我得到以下输出：“试图调用虚拟方法'android.content.res.Resources $ Theme android.content.Context.getTheme（ ）”上的空对象引用”

  

这是我的代码

    final Dialog dialog = new Dialog(getActivity());
    dialog.requestWindowFeature(Window.FEATURE_NO_TITLE); // before
    dialog.setContentView(R.layout.dialog_metka_aims);
    dialog.setCancelable(true);

    WindowManager.LayoutParams lp = new WindowManager.LayoutParams();
    lp.copyFrom(dialog.getWindow().getAttributes());
    lp.width = WindowManager.LayoutParams.WRAP_CONTENT;
    lp.height = WindowManager.LayoutParams.WRAP_CONTENT;

    dialog.getWindow().setBackgroundDrawable(new ColorDrawable(android.graphics.Color.TRANSPARENT));
    dialog.show();
    dialog.getWindow().setAttributes(lp);