android相关错误

1. Emulator: emulator: ERROR: GPU emulation is disabled.

http://blog.youkuaiyun.com/computerheart/article/details/73739577

这时需要检查一下 虚拟设备的设置，编辑设置时，将Graphics 修改为 Hardware-GLES2.0  后，保存设置，重新开启虚拟机即可正常打开。

2. javah生成jni头文件 

http://blog.youkuaiyun.com/jiuyueguang/article/details/9404237

两者结合，相当好用～

Error: cannot access android.app.Activity
  class file for android.app.Activity not found

The native methods declared in your java class is enough for generating JNI header. In your example, the command javah's option -classpath is not very useful. Suppose com/test/prueba/ACK.java is the class you process to generate JNI header. You can change the working directory to {project_dir}\src, execute the command

javah com.test.prueba.ACK

the corresponding JNI header file com_test_prueba_ACK.h will be created in the current directory.

3.  JNI项目提示“Unresolved inclusion: <jni.h>”的解决方案：

主要是这个target一开始为android-26，但是ndk里面最高到android-24，所以怎么改都不对。。

主要参考这个，其他的改过android target后没试过，不知道对不对

http://blog.youkuaiyun.com/songyuc/article/details/51339711

4.  Symbol 'NULL' could not be resolved

https://www.crifan.com/ubuntu_eclipse_cross_compile_symbol_null_could_not_be_resolved/

关键点：找到NULL的定义文件，将其加入c/c++  include中

5. 关于android某些手机java.lang.UnsatisfiedLinkError: No implementation found for ......的问题
关键点：libs不对应，建所有.so的libs

http://blog.youkuaiyun.com/xulike1990/article/details/54848323