Nice! I see this when the app loads "Error: a character vector argument expected". but doesn't affect it working at all

Yeah, I think that happens on startup because the plot gets called before you've even had a chance to load a shapefile. There should be some test conditions checked first - its why you see a lot of req(foo$bar) in shiny code...

Hi, I have this error when i try to upload a shapefile : "Error in xy.coords: 'x' and 'y' lenghts differ"

Do you know any solution ? thanks a lot !

Can you read the shapefile correctly using st_read? Are you uploading all four shapefile components (ie the .shp, .shx, .dbf and .prj files)? I just tested this snippet and it still works for me.

I can read the shapefile :

*Listening on http://127.0.0.1:7786
Upload dir is/tmp/RtmptMVO68/984dcb00eb9da2996c5a8eac
Reading layer `mmr_polbnda_adm0_250k_mimu' from data source `/tmp/RtmptMVO68/984dcb00eb9da2996c5a8eac/mmr_polbnda_adm0_250k_mimu.shp' using driver `ESRI Shapefile'
Simple feature collection with 1 feature and 6 fields
geometry type:  MULTIPOLYGON
dimension:      XY
bbox:           xmin: 92.17275 ymin: 9.671252 xmax: 101.1699 ymax: 28.54554
epsg (SRID):    4326
proj4string:    +proj=longlat +datum=WGS84 +no_defs
Warning: Error in xy.coords: 'x' and 'y' lengths differ*

I'm uploading just the four shapefile components yes. What I changed from your code is the position of the "plot(st_geometry(inShp()))".

It's now here :

leaflet() %>%
      addProviderTiles("Esri.WorldImagery", group = "Esri World Imagery", options = providerTileOptions(minZoom = 2, maxZoom = 17)) %>%
      addTiles(group = "OSM", options = providerTileOptions(minZoom = 2, maxZoom = 17)) %>%
      setView(lng = 96.221,lat = 20.792, zoom = 6 ) %>%
     ** plot(st_geometry(inShp()))**
      addLayersControl(baseGroups = c("Esri World Imagery", "OSM"))
  })

Is that the problem ?

Yes, that's not how the leaflet function works. You need to add a layer to it with one of the addSomething functions. Get it working outside of shiny before adding that complexity. Test it at the command line. Much faster turnaround.

Do you think that is possible ? To browse a shapefile on a Shiny app, and display it on Leaflet ? Because, i have some trouble finding good examples.