如何找出在一个GWT网格画布中选择了哪条线？

Question

I'm working on one GWT grid Canvas like this in the fiddle

My gridCanvas Object has horizontal lines represent paths. Also the object has vertical lines that represent sections.

I want to know how I could get the user's selection, for example, if the user has selected a route or a section and which route or section is selected.

Here a screenshot of case.

Answer 1

Add the event you want to listen to like gridCanvas.addClickHandler(ClickHandler) and use the ClickEvent to obtain the mouse position and calculate the cell the user clicked on.

gridCanvas.addClickHandler(new ClickHandler() {
   @Override
   public void onClick(ClickEvent event) {
       int row = event.getY() / getCellHeight();
       int col = event.getX() / getCellWidth();
   }
});

With getX() and getY() , you obtain the position of the mouse. Since you constructed the grid, you should also have the width and height of a cell. With this information, it is then easy to get the row and/or column.

I made a full sample that you can find here .

The sample is deployed here .