--- /dev/null
+
+usage of onscreenapp
+===
+
+## dependence
+
+- Onscreenapp depend on libhomescreen add agl-service-homescreen as below:
+ - libhomescreen must have 'showWindow/hideWindow/replyShowWindow' event
+ and 'showWindow/hideWindow/replyShowWindow' interface.
+ - agl-service-homescreen must have 'showWindow/hideWindow/replyShowWindow' verbs.
+
+## sequence
+
+show/hide onscreen sequence.
+- ![showOnscreen.svg](parts/showOnscreen.svg)
+
+## about sample 'onstestapp'
+onstestapp is a sample to use onscreenapp.
+
+### compile & install
+- compile
+ - when onscreenapp is compiled, this app's wgt file will exist at "onscreenapp/sample/package" which called onstestapp.wgt.
+
+- install
+ `afm-util install onstestapp.wgt;sync`
+
+### onstestapp usage
+- start onstestapp in launcher
+- select onscreen type in groupbox
+- press "Post" button
+
+After clicked onscreen's button,you will see reply information at top area of onstestapp.