ggplot2：带有facet_wrap的顶部图的x轴

Question

我正在制作一个多图图形，用于使用facet_wrap()与ggplot2发布。 x轴标签仅显示在底部图上，这很好，但顶部图上甚至没有轴。这降低了imo的可读性，我敢肯定大多数发布者都不会这样。

如何在没有标签的情况下获得x轴？

我的身材（带有一些快速的示例代码）：

代码：

library(ggplot2)

# theme settings (just to get the exact same example plot)
theme_set(theme_bw()) 
font <- "serif"
theme_update(axis.line = element_line(colour = "black"),
             axis.title.x = element_text(size = 16, colour = 'black', family = font),
             axis.title.y = element_text(size = 16, colour = 'black', family = font, angle = 90),
             axis.text.x = element_text(size = 14, colour = 'black', family = font),
             axis.text.y = element_text(size = 14, colour = 'black', family = font),
             legend.text = element_text(size = 12, colour = 'black', family = font),
             legend.title = element_blank(),
             legend.position = c(0.95,0.9),
             legend.box = "vertical",
             strip.text.x = element_text(size = 14, colour = 'black', family = font),
             strip.text.y = element_text(size = 14, colour = 'black', family = font, angle = -90),
             strip.text = element_text(hjust = 1),
             strip.background = element_blank(),
             panel.background = element_rect(fill = "white"),
             panel.grid.minor = element_blank(),
             panel.grid.major = element_blank(),
             panel.border = element_blank(),
             plot.title = element_text(size = 15, face = "bold", family = font, vjust = 1, hjust = 0.5))

# example data
count <- c(10,5,6,9,2,4,8,3,1,12,5,3)
stage <- rep(c("AD","NY"),6)
treat <- rep(c("A","B","C","D"),3)
days <- c(0,7,14,21,28,35,42,49,56,63,70,77)
df1 <- data.frame(count,stage,treat,days)

# example plot
ggplot(data=df1, aes(days,count,fill=stage)) +
  facet_wrap(~treat) +
  geom_col(position = "dodge",color="black") +
  #expand = put 0 on intersection
  scale_y_continuous(expand = c(0,0), limits = c(0,15)) + 
  scale_x_continuous(expand = c(0,0), limits = c(0,80)) +
  ylab("# per plant") +
  xlab("Days after release")