Question

我试图从jni调用java，不能正常工作，我做错了什么。

#include <jni.h>

    extern "C" {
    JNIEXPORT jboolean JNICALL Java_com_mycompany_myndkapp_HelloJni_stringFromJNI(JNIEnv* env, jobject thiz, jstring pkg)
    {

        try{

    //   context
    jclass native_context = env->GetObjectClass(thiz);

    // context.getPackageManager()
    jmethodID methodID_func = env->GetMethodID(native_context, "getPackageManager", "()Landroid/content/pm/PackageManager;");
    jobject package_manager  = env->CallObjectMethod(thiz,methodID_func);
    jclass pm_clazz = env->GetObjectClass(package_manager);

    //packageManager.getPackageInfo()
    jmethodID methodId_pm = env->GetMethodID(pm_clazz,"getPackageInfo","(Ljava/lang/String;I)Landroid/content/pm/PackageInfo;");

    env->CallObjectMethod(package_manager,methodId_pm,pkg,0);
     } catch(...)
     {
         return 0;
     }

    return 1;
     }
    }

如果安装了app，则返回true但未安装app强制关闭我的应用程序。

FATAL EXCEPTION: main
06-10 11:51:19.554 3768 3768 E     AndroidRuntime                               Process: com.mycompany.myndkapp, PID: 3768
06-10 11:51:19.554 3768 3768 E     AndroidRuntime                               java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mycompany.myndkapp/com.mycompany.myndkapp.HelloJni}: android.content.pm.PackageManager$NameNotFoundException: com.demo.ndk2
06-10 11:51:19.554 3768 3768 E     AndroidRuntime                               at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2455)
06-10 11:51:19.554 3768 3768 E     AndroidRuntime                               at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2517)
06-10 11:51:19.554 3768 3768 E     AndroidRuntime                               at android.app.ActivityThread.access$800(ActivityThread.java:162)

我如何修复并返回false应用程序未安装？

Answer 1

C ++的try / catch没有捕获Java异常。您需要的是ExceptionCheck和ExceptionClear：

env->CallObjectMethod(package_manager, methodId_pm, pkg, 0);
if (env->ExceptionCheck()) {
    env->ExceptionClear();
    return 0;
}
return 1;

（请注意，您应该将这些用于每个 JNI调用，这可能导致抛出Java异常）

检测是否安装了应用程序，不返回false

1 个答案: