JNI 无法确定Bitmap的签名

或者：

Error: Cannot determine signature for Bitmap

原因： javah 无法识别Android的bitmap

The Bitmap class belongs to the package "android.graphics.Bitmap", the javah tool does not recognize Android classes, so you must add the classpath option to javah command.

解决方法：

windows：

javah -classpath C:\PROGRA~2\Android\android-sdk\platforms\android-8\android.jar;. com.test.JniTest

linux/mac:

javah -classpath /Users/Android/android-sdk/platforms/android-xy/android.jar:. com.test.JniTest

参考：

http://stackoverflow.com/questions/22106539/android-ndk-javah-cannot-find-signature-for-bitmap?lq=1

http://stackoverflow.com/questions/7635624/android-javah-doesnt-find-my-class/7635758#7635758