support shift+click to select mutiple rows

[shrektan]

closes #305

[shrektan]

Here's my testing code.

library(shiny)

server <- function(input, output) {
  output$data <- DT::renderDT(
    DT::datatable(iris), server = F
  )
  output$data_sel <- renderText(input$data_rows_selected)
}
ui <- fluidPage(
  tagList(
    DT::DTOutput("data"),
    textOutput("data_sel")
  )
)

shinyApp(ui, server, options = list(port = 7995))

[yihui]

Overall this looks great! We need to prevent the text selection when holding Shift. I'll merge it and see if I can change it (presumably using https://api.jquery.com/event.preventdefault/).

[yihui]

I have fixed the text selection issue. The other thing is that this probably does not work in the server-processing mode (which is always tricky in DT)...

[shrektan]

Well, just confirm that there's indeed a small issue (not that small...), which is the selection range will be different between the server-processing mode and the client side mode.

1. select first row in page 1, let's assume it's row no 1;
2. press shift
3. select another row in another page, let's assume it's row no 20, and every page displays 5 row

In the client side mode, the row selection will be 1 to 20, while in the server-processing mode, it's 1, 16 to 20...

[yihui]

You need to use the vector DT_rows_current to convert the local row index to the index on the server side. You can see how I did it in changeInput('rows_selected') and changeInput('row_last_clicked'). Let me know if you are able to fix it. Thanks!

[shrektan]

I guess I should be able to fix it based on your current code, some ideas on server-processing mode:

• lastClickedRow and currentClickedRow (i.e., thisRow.index()) should be converted to the index on server side;
• shiftSelRows() should return the indexes on server side as well. Since on client side, the browser itself doesn't know what the real underlying data is, we can only convert the indexes relying on DT_rows_current.
• Select the rows based on server side indexes. Here's the tricky part, how can I be able to select rows that hasn't been loaded to the browsers yet? By looking at your implementation for selection = list(mode = "multiple", selected = c(1, 3, 8) I think it can be done by changing the value of selected1.

Will try to fix it tonight or tomorrow~

[yihui]

Sounds great!

[yihui]

我的 0.3 版本计划的事项现在还剩下两项：https://github.com/rstudio/DT/issues?q=is%3Aopen+is%3Aissue+milestone%3Av0.3 我先做 #28 去了，你这个事项需要比较细心的考虑，所以你慢慢来不着急，下周之前能捣鼓出来最好，捣鼓不出来也没事。多谢！

[shrektan]

恩恩，白天上班没什么时间 👨‍💼

昨天稍微鼓捣了下，要是没有幺蛾子的话，感觉应该可以弄出来。因为没有测试嘛，代码有无其他坏的影响，姑且只能由你来把关啦，哈哈哈。

[yihui]

嗯，我也只能用意念力在脑子里“测试”。