add examples

README.md

@@ -31,8 +31,18 @@
 
 LTUI is a cross-platform terminal ui library based on Lua. 
 
+## Build
+
+We need install the cross-platform build utility [xmake](https://github.com/tboox/xmake) first.
+
+```console
+$ xmake
+```
+
 ## Examples
 
+#### Window
+
 ```lua
 --  requires
 local ltui        = require("ltui")
@@ -61,6 +71,42 @@ end
 demo:run()
 ```
 
+#### Input dialog
+
+```lua
+--  requires
+local ltui        = require("ltui")
+local label       = ltui.label
+local button      = ltui.button
+local application = ltui.application
+local event       = ltui.event
+local rect        = ltui.rect
+local inputdialog = ltui.inputdialog
+
+-- the demo application
+local demo = application()
+
+-- init demo
+function demo:init()
+
+    -- init name 
+    application.init(self, "demo")
+
+    -- init background
+    self:background_set("blue")
+
+    -- init input dialog
+    local dialog_input = inputdialog:new("dialog.input", rect {0, 0, 50, 8})
+    dialog_input:text():text_set("please input text:")
+    dialog_input:button_add("no", "< No >", function (v) dialog_input:quit() end)
+    dialog_input:button_add("yes", "< Yes >", function (v) dialog_input:quit() end)
+    self:insert(dialog_input, {centerx = true, centery = true})
+end
+
+-- run demo
+demo:run()
+```
+
 ## Snapshot
 
 #### Menu configuation