Android JNI异常处理 [英] Android JNI exception handling

问题描述

我需要用JNI代码实现的异常处理。我不擅长jni，找不到任何好的榜样。因此，请为此提供完整的示例。

I need an exception handling implemented in JNI code. I am not good at jni and can't find any good example. So, please provide full example for this.

这就是我在做什么：

jint JNI_OnLoad(JavaVM* vm, void* reserved) {
    jint result = -1;
    g_JavaVM = vm;

    if (vm->GetEnv((void **) &envLocal, JNI_VERSION_1_6) != JNI_OK) {

        return -1;
    }

    jclass clazz;
    **clazz = envLocal->FindClass("com/graphics/myclass/MyClass");**
    if (clazz == NULL)
        __android_log_print(ANDROID_LOG_ERROR, "MyClass",
                "clazz value is null");
    g_clazz = (jclass) envLocal->NewGlobalRef(clazz);

    // STEP 3/3 : Delete the no longer needed local reference
    envLocal->DeleteLocalRef(clazz);
    result = JNI_VERSION_1_6;
    return result;
}

现在我需要在哪里无法使用此MyClass（因为应用程序开发人员没有相应的jar文件），则不应有任何应用崩溃。
使用System.LoadLibrary（ libmyclass.so）和此 com / graphics / myclass / MyClass类加载库时，将调用JNI_OnLoad。

Now I have a need where if this MyClass is not available (because app developer does not have corresponding jar file) then, there should not be any app crash. JNI_OnLoad will be called when loading a library using System.LoadLibrary("libmyclass.so") and this "com/graphics/myclass/MyClass" class.

当前，如果此jar不包含在应用程序中，则会导致应用程序崩溃并出现以下异常

Currently, if this jar is not included in the app this causes and app to crash with below exception

F/art     (14708): sart/runtime/check_jni.cc:65] JNI DETECTED ERROR IN APPLICATION: JNI NewGlobalRef called with pending exception 'java.lang.ClassNotFoundException' thrown in unknown throw location
F/art     (14708): sart/runtime/check_jni.cc:65]     in call to NewGlobalRef
F/art     (14708): sart/runtime/check_jni.cc:65]     from java.lang.String java.lang.Runtime.nativeLoad(java.lang.String, java.lang.ClassLoader, java.lang.String)
F/art     (14708): sart/runtime/check_jni.cc:65] "main" prio=5 tid=1 Runnable

我需要的是由Android在某处处理的此异常，应在JNI_OnLoad中进行处理，以使应用程序不会崩溃。我不希望通过Java处理异常。

What I need is rather this exception handled by android somewhere, it should be handled in JNI_OnLoad so that app does not crash. I don't want exception handling by java.

所以我的想法是，如果我捕获到由 clazz = envLocal-> FindClass（ com / graphics / systemOp / SystemOp）;

so my thinking is if I catch exception thrown by " clazz = envLocal->FindClass("com/graphics/systemOp/SystemOp");" be handled in JNI_OnLoad after this.

有人可以提出一个示例（完整示例），因为我无法实现它。

Can someone suggest an example (complete one) because I can't implement it. With full source code please. Ask me if you need more information.

推荐答案

您可以在执行可能会抛出的jni操作后调用以下代码：

You can call following code after doing jni operations that may throw:

bool checkExc(JNIEnv* env) {
 if(env->ExceptionCheck()) {
  env->ExceptionDescribe(); // writes to logcat
  env->ExceptionClear();
  return true;
 }
 return false;
}

这篇关于Android JNI异常处理的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！