如何将 int 放入 HashMap jni?

how to put int in HashMap jni?

本文关键字：HashMap jni 放入 int      更新时间：2023-10-16

我有这样的方法

jobject Profiling::getFullStatistic(JNIEnv *env)
{
    env->PushLocalFrame(256); // fix for local references
    jclass mapClass = env->FindClass("java/util/HashMap");
    if (mapClass == nullptr)
    {
        return nullptr;
    }
    jmethodID init = env->GetMethodID(mapClass, "<init>", "(I)V");
    jobject hashMap = env->NewObject(mapClass, init, m_values.size());
    jmethodID put = env->GetMethodID(mapClass, "put", "(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;");
    for (auto &it: m_values)
    {
        env->CallObjectMethod(hashMap, put, env->NewStringUTF(it.first.c_str()), env->NewStringUTF(std::to_string(it.second).c_str()));
    }
    return env->PopLocalFrame(hashMap);
}

最后我得到Map<String, String>，现在我想将此地图类型更改为Map<String, Integer>

所以，我只是将put方法的签名更改为

jmethodID put = env->GetMethodID(mapClass, "put", "(Ljava/lang/Object;I;)Ljava/lang/Object;");

据我所知int签名是I...

我也改变了这条线 

env->CallObjectMethod(hashMap, put, env->NewStringUTF(it.first.c_str()), it.second);

但知道我有这样的错误

JNI DETECTED ERROR IN APPLICATION: JNI NewStringUTF called with pending 
exception java.lang.NoSuchMethodError: no non-static method 
"Ljava/util/HashMap;.put(Ljava/lang/Object;I;)Ljava/lang/Object;"
at java.util.Map com..ar.JniInterface.getProfilingStatistic(long) 
(JniInterface.java:-2)
at void com..ar.ui.fragments.ar.ArScreen.lambda$testDeleteIt$1$ArScreen() 
(ArScreen.java:156)
at void 
com..ar.ui.fragments.ar.-$$Lambda$ArScreen$zqdXNYFzVzmF_ZYFKJRM26bZzUw.run() 
(lambda:-1)
at void android.os.Handler.handleCallback(android.os.Message) 
(Handler.java:873)
at void android.os.Handler.dispatchMessage(android.os.Message) 
(Handler.java:99)
at void android.os.Looper.loop() (Looper.java:214)
at void android.app.ActivityThread.main(java.lang.String[]) 
(ActivityThread.java:6990)
at java.lang.Object java.lang.reflect.Method.invoke(java.lang.Object, 
java.lang.Object[]) (Method.java:-2)
at void com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run() 
(RuntimeInit.java:493)
 at void com.android.internal.os.ZygoteInit.main(java.lang.String[]) 
(ZygoteInit.java:1445)
 in call to NewStringUTF
 from java.util.Map com..ar.JniInterface.getProfilingStatistic(long)
 "main" prio=5 tid=1 Runnable
 | group="main" sCount=0 dsCount=0 flags=0 obj=0x76dbefb8 self=0x759e614c00
 | sysTid=18571 nice=-10 cgrp=default sched=0/0 handle=0x76251b3560
 | state=R schedstat=( 1106979853 124044847 973 ) utm=95 stm=15 core=4 HZ=100
 | stack=0x7fc9911000-0x7fc9913000 stackSize=8MB
 | held mutexes= "mutator lock"(shared held)

编辑

如果我尝试将 int 作为整数传递(如@Botje mantioned(

jobject Profiling：：getFullStatistic(JNIEnv *env( { env->PushLocalFrame(256(;修复本地引用

    jclass mapClass = env->FindClass("java/util/HashMap");
    if (mapClass == nullptr)
    {
        return nullptr;
    }
    jmethodID init = env->GetMethodID(mapClass, "<init>", "(I)V");
    jobject hashMap = env->NewObject(mapClass, init, m_values.size());
    jmethodID put = env->GetMethodID(mapClass, "put", "(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;");
    jclass j_Integer = env->FindClass("java/lang/Integer");
    jmethodID j_Integer_valueOf = env->GetMethodID(j_Integer, "valueOf", "(I)Ljava/lang/Integer;");
    for (auto &it: m_values)
    {
        jobject j_intValue = env->CallStaticObjectMethod(j_Integer, j_Integer_valueOf, it.second);
        env->CallObjectMethod(hashMap, put, env->NewStringUTF(it.first.c_str()), j_intValue);
    }
    return env->PopLocalFrame(hashMap);
}

我得到这样的错误

JNI

在应用程序中检测到错误：JNI CallStaticObjectMethodV 调用，并带有挂起的异常 java.lang.NoSuchMethodError：无非静态方法 "Ljava/lang/Integer;.valueOf(I(Ljava/lang/Integer;">

从C++调用Integer#valueOf(int)并将结果传递给HashMap#put(Object, Object)：

jclass j_Integer = env->FindClass("java/lang/Integer");
jmethodID j_Integer_valueOf = env->GetStaticMethodID(j_Integer, "valueOf", "(I)Ljava/lang/Integer;");
jmethodID put = env->GetMethodID(mapClass, "put", "(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;");
for (auto &it: m_values) {
    jobject j_intValue = env->CallStaticObjectMethod(j_Integer, j_Integer_valueOf, it.second);
    env->CallObjectMethod(hashMap, put, env->NewStringUTF(it.first.c_str()), j_intValue);
}
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