Question

我正在尝试在Xamarin.Android中将Java类转换为C＃。

原始的Java类有这个：

private native boolean OpenDeviceCtx(Object obj);
public native boolean CloseDevice();
public native boolean GetDiodesStatus(byte[] bArr);
public native boolean GetFrame(byte[] bArr);
public native boolean GetImage(int i, byte[] bArr);
public native boolean GetImage2(int i, byte[] bArr);
public native boolean GetImageByVariableDose(int i, byte[] bArr);
public native boolean GetImageSize();
public native boolean GetInterfaces(byte[] bArr);
public native String GetVersionInfo();
public native boolean IsFingerPresent();
public native boolean OpenDevice();
public native boolean OpenDeviceOnInterface(int i);
public native boolean Restore7Bytes(byte[] bArr);
public native boolean RestoreSecret7Bytes(byte[] bArr, byte[] bArr2);
public native boolean Save7Bytes(byte[] bArr);
public native boolean SaveSecret7Bytes(byte[] bArr, byte[] bArr2);
public native boolean SetDiodesStatus(int i, int i2);
public native boolean SetGlobalSyncDir(String str);
public native boolean SetLogOptions(int i, int i2);
public native boolean SetNewAuthorizationCode(byte[] bArr);
public native boolean SetOptions(int i, int i2);

static {
    System.loadLibrary("usb-1.0");
    System.loadLibrary("ftrScanAPI");
    System.loadLibrary("ftrScanApiAndroidJni");
}

我认为这种“原生”方法是.so库中的方法。我是对的吗？

因此，要在我的Xamarin.Android项目中加载这些库，我尝试这样做：

[DllImport("usb-1.0")]
public static extern int GetUSB();
[DllImport("ftrScanAPI")]
public static extern int GetScanAPI();
[DllImport("ftrScanApiAndroidJni")]
public static extern int GetScanAPIAndroidJNI();

在我的项目中创建了一个文件夹结构，如： project / lib / arm / files.so

当我运行项目时，我遇到了很多错误：

DllImport attempting to load: 'usb-1.0'.
DllImport error loading library '/storage/emulated/0/Android/data/RDScanFingerprint.RDScanFingerprint/files/.__override__/libusb-1.0': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm//storage/emulated/0/Android/data/RDScanFingerprint.RDScanFingerprint/files/.__override__/libusb-1.0" not found'.
DllImport error loading library '/storage/emulated/0/Android/data/RDScanFingerprint.RDScanFingerprint/files/.__override__/libusb-1.0.so': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm//storage/emulated/0/Android/data/RDScanFingerprint.RDScanFingerprint/files/.__override__/libusb-1.0.so" not found'.
DllImport error loading library '/system/lib/libusb-1.0': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm//system/lib/libusb-1.0" not found'.
DllImport error loading library '/system/lib/libusb-1.0.so': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm//system/lib/libusb-1.0.so" not found'.
DllImport error loading library 'libusb-1.0': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm/libusb-1.0" not found'.
DllImport error loading library 'libusb-1.0.so': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm/libusb-1.0.so" not found'.
DllImport error loading library 'usb-1.0': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm/usb-1.0" not found'.
DllImport error loading library '/storage/emulated/0/Android/data/RDScanFingerprint.RDScanFingerprint/files/.__override__/libusb-1.0': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm//storage/emulated/0/Android/data/RDScanFingerprint.RDScanFingerprint/files/.__override__/libusb-1.0" not found'.
DllImport error loading library '/storage/emulated/0/Android/data/RDScanFingerprint.RDScanFingerprint/files/.__override__/libusb-1.0.so': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm//storage/emulated/0/Android/data/RDScanFingerprint.RDScanFingerprint/files/.__override__/libusb-1.0.so" not found'.
DllImport error loading library '/system/lib/libusb-1.0': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm//system/lib/libusb-1.0" not found'.
DllImport error loading library '/system/lib/libusb-1.0.so': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm//system/lib/libusb-1.0.so" not found'.
DllImport error loading library 'libusb-1.0': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm/libusb-1.0" not found'.
DllImport error loading library 'libusb-1.0.so': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm/libusb-1.0.so" not found'.
DllImport error loading library 'libusb-1.0': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm/libusb-1.0" not found'.
DllImport unable to load library 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm/libusb-1.0" not found'.
DllImport attempting to load: 'usb-1.0'.
DllImport error loading library '/storage/emulated/0/Android/data/RDScanFingerprint.RDScanFingerprint/files/.__override__/libusb-1.0': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm//storage/emulated/0/Android/data/RDScanFingerprint.RDScanFingerprint/files/.__override__/libusb-1.0" not found'.
DllImport error loading library '/storage/emulated/0/Android/data/RDScanFingerprint.RDScanFingerprint/files/.__override__/libusb-1.0.so': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm//storage/emulated/0/Android/data/RDScanFingerprint.RDScanFingerprint/files/.__override__/libusb-1.0.so" not found'.
DllImport error loading library '/system/lib/libusb-1.0': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm//system/lib/libusb-1.0" not found'.
DllImport error loading library '/system/lib/libusb-1.0.so': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm//system/lib/libusb-1.0.so" not found'.
DllImport error loading library 'libusb-1.0': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm/libusb-1.0" not found'.
DllImport error loading library 'libusb-1.0.so': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm/libusb-1.0.so" not found'.
DllImport error loading library 'usb-1.0': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm/usb-1.0" not found'.
DllImport error loading library '/storage/emulated/0/Android/data/RDScanFingerprint.RDScanFingerprint/files/.__override__/libusb-1.0': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm//storage/emulated/0/Android/data/RDScanFingerprint.RDScanFingerprint/files/.__override__/libusb-1.0" not found'.
DllImport error loading library '/storage/emulated/0/Android/data/RDScanFingerprint.RDScanFingerprint/files/.__override__/libusb-1.0.so': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm//storage/emulated/0/Android/data/RDScanFingerprint.RDScanFingerprint/files/.__override__/libusb-1.0.so" not found'.
DllImport error loading library '/system/lib/libusb-1.0': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm//system/lib/libusb-1.0" not found'.
DllImport error loading library '/system/lib/libusb-1.0.so': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm//system/lib/libusb-1.0.so" not found'.
DllImport error loading library 'libusb-1.0': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm/libusb-1.0" not found'.
DllImport error loading library 'libusb-1.0.so': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm/libusb-1.0.so" not found'.
DllImport error loading library 'libusb-1.0': 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm/libusb-1.0" not found'.
DllImport unable to load library 'dlopen failed: library "/data/app/RDScanFingerprint.RDScanFingerprint-1/lib/arm/libusb-1.0" not found'.

知道我做错了什么？

Answer 1

如果您使用的是Visual Studio，并且正在向Xamarin移植一些已在Android上运行的JNI-Java代码，请按照以下步骤操作：

将.so文件放在Xamarin项目的“lib”文件夹下，例如：
确保您的.so文件设置为“Build Action”到“Android Native Library”
- 右键单击您的.so文件 - ＆gt;属性

在C＃-Xamarin中，您可以按以下方式加载库

try
{
    JavaSystem.LoadLibrary("SDL2");
    JavaSystem.LoadLibrary("glib-2.0");
    JavaSystem.LoadLibrary("gthread-2.0");
    JavaSystem.LoadLibrary("fluidsynth");
    JavaSystem.LoadLibrary("sdl_mixer");
    JavaSystem.LoadLibrary("initmixer");
}
catch (UnsatisfiedLinkError e)
{
    return e.Message;
}

C＃中的本机方法必须按以下方式声明：

[DllImport("initmixer", EntryPoint = "Java_sf2Tools_FluidsynthJNI_loadSong")]
public static extern int loadSong(IntPtr env, IntPtr thiz, IntPtr songPath, int miliseconds);
[DllImport("initmixer", EntryPoint = "Java_sf2Tools_FluidsynthJNI_isPlaying")]
public static extern int isPlaying();
[DllImport("initmixer", EntryPoint = "Java_sf2Tools_FluidsynthJNI_pauseAudio")]
public static extern void pauseAudio();
[DllImport("initmixer", EntryPoint = "Java_sf2Tools_FluidsynthJNI_resumeAudio")]
public static extern void resumeAudio();
[DllImport("initmixer", EntryPoint = "Java_sf2Tools_FluidsynthJNI_stopAudio")]
public static extern void stopAudio();
[DllImport("initmixer", EntryPoint = "Java_sf2Tools_FluidsynthJNI_setSoundfonts")]
public static extern void setSoundfonts(IntPtr env, IntPtr thiz, IntPtr js);

在“EntryPoint”字段中，您必须将函数的名称与C / C ++代码中的名称完全相同，通常为Java_your_package_name_YourClassName_YourMethodName。

例如，这是我原来的C ++代码：

void Java_sf2Tools_FluidsynthJNI_setSoundfonts(JNIEnv * env, jobject this, jstring js)
{
    //Some code
}
void Java_sf2Tools_FluidsynthJNI_pauseAudio(JNIEnv * env, jobject this)
{
    //Some code
}
void Java_sf2Tools_FluidsynthJNI_resumeAudio(JNIEnv * env, jobject this)
{
    //Some code
}
int Java_sf2Tools_FluidsynthJNI_isPlaying(JNIEnv * env, jobject this)
{
    //Some code
}
void Java_sf2Tools_FluidsynthJNI_stopAudio(JNIEnv * env, jobject this)
{
    //Some code
}

int Java_sf2Tools_FluidsynthJNI_loadSong(JNIEnv * env, jobject this, jstring songPath)
{
    //Some code
}

或者查看通常会让Android Studio知道您的原生函数全名的警告：

在C＃Xamarin中，有时你不能跳过你在java中所做的参数：JNIEnv * env，或者这个参数，你应该使用IntPtr作为这个参数的vartype。例如，为了调用loadSong函数，我使用了以下参数。

C / C ++

void Java_sf2Tools_FluidsynthJNI_setSoundfonts(JNIEnv * env, jobject this, jstring js)

fluidsynth.setSoundfonts(JNIEnv.Handle, System.IntPtr.Zero, new Java.Lang.String(getCFGPathFiltered()).Handle);

注意以“j”开头的C ++参数，例如：jstring，jint，你不能在jstring上使用C＃字符串，例如，你应该使用：

jstring - ＆gt; new Java.Lang.String（“sampleString”）。句柄 - ＆gt; System.IntPtr

jint - ＆gt; new Java.Lang.Integer（4）.Handle - ＆gt; System.IntPtr

在Xamarin.Android中加载.so文件

1 个答案: