Resolve dialog disappear when switching between portrait and screen

Taking Alertdialog as an example

First, the Alertdialog view is encapsulated in an instance of Dialogfragment (Fragmentdealertdialog subclass)

Package com.example.t;

Import Android.app.AlertDialog;
Import Android.app.Dialog;
Import Android.os.Bundle;
Import Android.widget.DatePicker;

public class Dialogpickerfragment extends Android.support.v4.app.DialogFragment {
@Override
Public Dialog Oncreatedialog (Bundle savedinstancestate) {
DatePicker DP = new DatePicker (getactivity ());
return new Alertdialog.builder (Getactivity ())
. Setview (DP)
. Settitle ("Dialog")
. Setpositivebutton ("OK", NULL)
. Create ();
}
}

Second, call in activity

public void Dialogpicker (View v) {
Fragmentmanager fm = Getsupportfragmentmanager ();
Dialogpickerfragment dialog = new Dialogpickerfragment ();
DIALOG.SHOW (FM, "date");
}

Resolve dialog disappear when switching between portrait and screen