Trigger onitemselected event when using reflection to let spinner select the same option

Look at the source code, spinner judge whether to trigger Onitemselected, is in its base class Adapterview inside Do:

    void Checkselectionchanged () {        if (mselectedposition! = moldselectedposition) | | (Mselectedrowid! = Moldselectedrowid)) {            selectionchanged ();            Moldselectedposition = mselectedposition;            Moldselectedrowid = Mselectedrowid;        }    }

methods checkselectionchanged and variable moldselectedposition are adapterview private, and we cannot inherit spinner overrides. However, using Java 's reflection, we can violently modify the value of moldselectedposition:

New Onitemselectedlistener () {@Overridepublic void onitemselected (adapterview<?> arg0, View arg1,int arg2, long ARG3) {//TODO auto-generated method Stubtry {//The following three lines of code is the solution to the problem field field = AdapterView.class.getDeclaredField (" Moldselectedposition "); Field.setaccessible (true);//Set Moldselectedposition accessible Field.setint (spinner, Adapterview.invalid_position); Set the value of Moldselectedposition} catch (Exception e) {e.printstacktrace ();}} @Overridepublic void onnothingselected (adapterview<?> arg0) {//TODO auto-generated Method stub}};

Every time we choose, we change the value of moldselectedposition so that every time mselectedposition! = Moldselectedposition is judged to be true, Then the onitemselected will always be triggeredto achieve our goal.

To implement spinner selected events through code:

Spinner.performitemclick (Suborderslistview.getchildat (ordermenuposition), Ordermenuposition,
Suborderslistview.getitemidatposition (ordermenuposition));

Trigger onitemselected event when using reflection to let spinner select the same option