Boxplot and xyplot overlapped

Question

I've done a conditional boxplot with my data, with the bwplot function of the lattice library.

    A1 <- bwplot(measure ~ month | plot , data = prueba,
              strip = strip.custom(bg = 'white'),   
              cex = .8, layout = c(2, 2),
              xlab = "Month", ylab = "Total",
              par.settings = list(
                box.rectangle = list(col = 1),
                box.umbrella  = list(col = 1),
                plot.symbol   = list(cex = .8, col = 1)),
              scales = list(x = list(relation = "same"),
                            y = list(relation = "same")))

Then, I've done a xyplot because I want to add the precipitation data to the previous graph, using xyplot from lattice library also.

    B1 <- xyplot(precip ~ month | plot, data=prueba,
   type="b",
   ylab = '% precip',
   xlab = 'month',
   strip = function(bg = 'white', ...)
     strip.default(bg = 'white', ...),
   scales = list(alternating = F,
                 x=list(relation = 'same'),
                 y=list(relation = 'same')))

I've try to draw them on the same graph using grid.arrange from gridExtra library:

    grid.arrange(A1,B1)

But with this, I don't overlap the data, but the result is this

How could I draw the precipitacion data "inside" the boxplots conditioned by plot?

Thank you

Answer 1

Using the barley data as Andrie did, another approach with latticeExtra:

library(lattice)
library(latticeExtra)

bwplot(yield ~ year | variety , data = barley, fill = "grey") +
xyplot(yield ~ year | variety , data = barley, col = "red")