Type 'std::string' could not be resolved.

Question

I'd started porting some Java code in native c++ in Android. I have an issue with using strings in c++:

Type 'std::string' could not be resolved

There is my sample code

#include <jni.h>
#include <lexu_me_test_native.h>
#include <string.h>
using namespace std;

JNIEXPORT jstring JNICALL Java_lexu_me_test_native_prepairToShowNative
  (JNIEnv * env, jclass javaThis, jstring str)
{
    jboolean blnIsCopy;
    jstring jstrOutput;
    char* strCOut;
    std::string ss;

    const char* strCIn = (env)->GetStringUTFChars(str , &blnIsCopy);
    // convert jstring to a char array
    // Do stuff with the char array and and store the result
    // in another char array strCOut
    (env)->ReleaseStringUTFChars(str , strCIn); // release jstring

    jstrOutput = (env)->NewStringUTF(strCOut); // convert char array to jstring
    return jstrOutput;
}

Android.mk file:

LOCAL_PATH := $(call my-dir)

include $(CLEAR_VARS)

LOCAL_MODULE    := native
LOCAL_SRC_FILES := native.cpp

include $(BUILD_SHARED_LIBRARY)

Application.mk file:

APP_STL := stlport_static

MinGW installed and added to path. I tried using android-ndk-r8e and android-ndk-r8-crystax-1 nothing helped. In Cygwin Terminal errors:

Compile++ thumb  : native <= native.cpp
jni/native.cpp: In function '_jstring* Java_lexu_me_test_native_prepairToShowNative(JNIEnv*, jclass, jstring)':
jni/native.cpp:11:2: error: 'string' was not declared in this scope
jni/native.cpp:11:9: error: expected ';' before 'ss'

I'm using Win 7 64bit. Can anyone say how it could be solved? Thanks.

EDIT.

In C/C++ General - Path and Symbols already set: C:\Android\android-ndk-r8e\platforms\android-14\arch-arm\usr\include

Solution

If the other answers didn't work, then try these steps:

1. If you have using namespace std;, use string instead of std::string.
2. If #include <string> doesn't work and you're using Linux, try #include <unistd.h>. If you're using another OS, use #include <cstdlib>.

Comments

[LEX]

Hi, I'm changed std::string to string, and added #include <string>. But Eclipse show errors "Type 'string' could not be resolved" although in cygwin compile fine.

[Shervin Sorouri]

Then eclipse has a problem but i suggest you try #include <cstdlib> for windows or #include <unistd.h> for linux instead of #include <string>

[LEX]

#include <cstdlib> Eclipse accepted it, but warning didn't hide and compile in cygwing show error "'string' was not declared in this scope"

[Shervin Sorouri]

now i am sure that your computer doesn't have the string header or your ide(Eclipse) is broken.

[Shervin Sorouri]

i recommend visual studio if your a windows user because its really easy to work with and its free. go check it at Microsoft's website

[IInspectable]

@shervin Visual Studio and Android's NDK aren't exactly best friends. It is possible to integrate the NDK into Visual Studio. However, vs-android is flaky, at best. And VisualGDB is a commercial product that requires a commercial Visual Studio Edition.

[Parag Bafna]

This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post.

[Joe Plante]

Wow was this a long time ago. I'll update the answer. However, see kandroid.org/ndk/docs/CPLUSPLUS-SUPPORT.html

[jww]

"But Eclipse show errors "Type 'string' could not be resolved" although in cygwin compile fine..." - Also see Android NDK build, Method could not be resolved. Eclipse and the plugin broke during a NDK update and it was never fixed. It was never fixed presumably because of Android Studio, which does not support JNI...