Opencv 4 Android 问题汇总：

1,No rule to make target needed by *.so问题的解决

问题：

Android NDK:     This is likely to result in incorrect builds. Try using LOCAL_STATIC_LIBRARIES    

Android NDK:     or LOCAL_SHARED_LIBRARIES instead to list the library dependencies of the    
Android NDK:     current module    

make.exe: *** No rule to make target `jni/JNIterface.cpp', needed by `obj/local/armeabi/objs/JNIterface/JNIterface.o'.  Stop.

这是由于有些源文件（jni/JNIterface.cpp）没有指定造成的。自习检查jni/JNIterface.cpp是否写错了，改正即可。