为什么Intent.ACTION_SEND对话有第二次延迟？

Question

ProgressDialog progressDialog = new ProgressDialog(context);
progressDialog.setMessage("Waitting...");
progressDialog.show();
//sharing implementation
Intent sharingIntent = new Intent(android.content.Intent.ACTION_SEND);
// what type of data needs to be send by sharing
sharingIntent.setType("text/plain");
// package names
PackageManager pm = context.getPackageManager();
// list package
List<ResolveInfo> activityList = pm.queryIntentActivities(sharingIntent, 0);
List<ResolveInfo> newActivityList = new ArrayList<>();

以上是我的代码。问题是ProgressDialog有第二次延迟显示。谁能告诉我为什么？