Build errors while trying to set up OpenCV4Android

Question

I am trying to run an OpenCV4Android in my eclipse. I am working on Linux(CentOS 6). I have done everything mentioned in this link but I am still getting build errors. I have also set the NDK path in preferences hat is not mentioned in the tutorial and tried a lot more things. When I try to build the library project the console gives:

"Cannot run program "/ndk-build": Unknown reason
 Error: Program "/ndk-build" is not found in PATH"

All the projects also have build errors and the src and gen folders in openCV4 Library is not created and the build path shows:

"Unable to get system library for the project" 

When i try to change the project properties I get an error saying the page contains invalid values and I cannot change the android api version. Plz help. Have been trying to set this up since 3 days now. Thank you.

Answer 1

First Clean and Build you library Project alone and then try cleaning all your projects. In order to solve the "Cannot run program "/ndk-build": Unknown reason Error: Program "/ndk-build" is not found in PATH" error, Try the following steps:

Head to the project's properties. If you're using Windows, the shortcut is Alt + Enter; or simply right-click the project name to find its properties.

Go to the C/C++ Build section; under Builder Settings tab in Build command: text box you're likely to find something similar to that below, if it's empty then type in the similar text - namely: ${NDKROOT}/ndk-build.cmd where NDKROOT, as its name implies, refers to the path where your NDK root folder exists.

Now you must inform eclipse what NDKROOT equates to; as in, where is the NDK root path. You can do this by heading to (in your project's properties) C/C++ Build > Environment > press Add…

Now add your environment variable named NDKROOT (the Name) with the relevant path (Value). Note that you're to repeat this per NDK project. You would get a window similar to that below.

Press OK to the New variable input window and then OK again to the properties window.

Hopefully this will help!