function NextFormFieldIndexForPage(FormHandle: FPDF_FORMHANDLE; Page: FPDF_PAGE; CurrentIndex: Integer; GoForward: Boolean): Integer;
| FormHandle | FPDF_FORMHANDLE |
| Page | FPDF_PAGE |
| CurrentIndex | Integer |
| GoForward | Boolean |
IntegerNextFormFieldIndexForPage 遍历一页的控件注释顺序,并返回相对于 CurrentIndex 的下一个候选索引
将 GoForward 设为 True 表示向前 Tab 导航,设为 False 表示反向导航
NextIndex := NextFormFieldIndexForPage(Pdf1.FormHandle, Pdf1.Page, Pdf1.FocusedFormFieldIndex, True);