## Android NDK: APP variable defined to unknown applications: hello-jni 在使用android-ndk-r4b用命令make APP=hello-jni編譯hello-jni例子的時候，出現了以下錯誤信息： ~~~ Android NDK: APP variable defined to unknown applications: hello-jni Android NDK: You might want to use one of the following: build/core/main.mk:81: *** Android NDK: Aborting . Stop. ~~~ 在查閱了OVERVIEW.TXT后，才發現r4b中編譯的時候是以下步驟： ~~~ 1/ Place your native sources under $PROJECT/jni/... 2/ Write $PROJECT/jni/Android.mk to describe your sources to the NDK build system 3/ Optional: write $PROJECT/jni/Application.mk to describe your project in more details to the build system. You don't need one to get started though, but this allows you to target more than one CPU or override compiler/linker flags (see docs/APPLICATION-MK.TXT for all details). 4/ Build your native code by running "$NDK/ndk-build" from your project directory, or any of its sub-directories. ~~~ 照著做就編譯成功了，如圖：  > 本文轉自： > [http://mp870601.blog.163.com/blog/static/13675745320107824850564/](http://mp870601.blog.163.com/blog/static/13675745320107824850564/) > linc注：在r5b中也是一樣，現在ndk的文章從網上一搜都是以前的，所以照著做會出現很多問題。希望大家還是以幫助文檔為主。這樣就能以不變應萬變。