sit(a, "action", "android.intent.action.SEND")
sit(a, "type", "application/vnd.android.package-archive")
sit(a, "extra", "android.intent.extra.STREAM","/sdcard/iapp.apk")
.这个是软件路径"/sdcard/iapp.apk"，
uit(a, "chooser", "分享软件")