By default, adding a checkbox into grid results in the checkbox being placed towards the left of the grid cell. One of the ways to position it towards the center is by using an additional grid layout of a single row and column inside the parent grid cell and then modifying grid layout to place the child grid accordingly. One possible layout configuration can be:
app.GridLayout2 = uigridlayout(app.GridLayout);
app.GridLayout2.ColumnWidth = {'1x'};
app.GridLayout2.RowHeight = {'1x'};
app.GridLayout2.Padding = [60 10 60 10];
Depending on padding values the single cell grid will be placed, and then adding a checkbox into this grid positions it into the center of parent grid cell. Kindly refer this documetation to understand more about grid layout properties.
