将C ++代码移植到Android时出现“无效参数”

Question

I am trying to port the following piece of C++ code to Android as part of some NDK work:

#include <fstream>

// ...

inline void trim(string & str, const string & delim = " \t\r\n")
{
    string::size_type pos = str.find_last_not_of(delim);
    if(pos == string::npos) str.erase(str.begin(), str.end());
    else
    {
        str.erase(pos+1);
        pos = str.find_first_not_of(delim);
        if(pos != string::npos) str.erase(0, pos);
    }
}

What I get is the following message at str.erase(pos+1); and str.erase(0, pos) :

Invalid arguments '
Candidates are:
std::basic_string<char,std::char_traits<char>,std::allocator<char>> & erase(?, ?)
__gnu_cxx::__normal_iterator<char *,std::basic_string<char,std::char_traits<char>,std::allocator<char>>>    erase(__gnu_cxx::__normal_iterator<char *,std::basic_string<char,std::char_traits<char>,std::allocator<char>>>)
__gnu_cxx::__normal_iterator<char *,std::basic_string<char,std::char_traits<char>,std::allocator<char>>>     erase(__gnu_cxx::__normal_iterator<char *,std::basic_string<char,std::char_traits<char>,std::allocator<char>>>,     __gnu_cxx::__normal_iterator<char *,std::basic_string<char,std::char_traits<char>,std::allocator<char>>>)
'

I tried what was suggested here but it did not help. Instead, now I am getting a new message for #include <fstream> :

Unresolved inclusion: <fstream>

What do I need to do to resolve this? Thank you.

UPDATE: I am trying to add this piece of code to an existing C++ code in an Android project that built and ran fine. When I applied the change linked to above, I not only got the unresolved inclusion for fstream, I also got a bunch of other errors. For instance, for the following block form the existing code:

#include <jni.h>
#include <opencv2/core/core.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/features2d/features2d.hpp>
#include <vector>

I am also getting Unresolved inclusion errors. So it made things worse.

Answer 1

尝试将以下行添加到您的项目的Application.mk 。

APP_STL := gnustl_static