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尝试将以下内容从 Java 代码传递到共享 C 库 .so。我对 JNA 很陌生,如果有人能指出我正确的方向,我将不胜感激。

我得到的错误是: java.lang.Error: Structure.getFieldOrder() on class com.dataTypes.TCIMUEvent does not provide enough names [0] ([]) to match declared fields [11] ([accel, accelValid,陀螺仪, gyroValid, mag, magValid, 压力, pressureValid, 温度, temperatureValid, 时间])

两个相关的对象/结构:

public class Motion extends Structure {

    public TCIMUEvent tcimuEvent;
    public int Status;
    public double userHeadingDeg;
    public float rotationMode;

    public Motion() {
    }

    public TCIMUEvent getTcimuEvent() {
        return tcimuEvent;
    }

    public Motion(TCIMUEvent tcimuEvent, int status, double userHeadingDeg, float rotationMode) {
        this.tcimuEvent = tcimuEvent;
        Status = status;
        this.userHeadingDeg = userHeadingDeg;
        this.rotationMode = rotationMode;
    }
public class TCIMUEvent extends Structure {

    public double time;
    public float[] accel;
    public boolean accelValid;
    public float[] mag;
    public boolean magValid;
    public float[] gyro;
    public boolean gyroValid;
    public float pressure;
    public boolean pressureValid;
    public float temperature;
    public boolean temperatureValid;

    public TCIMUEvent(double time, float[] accel, boolean accelValid, float[] mag, boolean magValid, float[] gyro, boolean gyroValid, float pressure, boolean pressureValid, float temperature, boolean temperatureValid) {
        this.time = time;
        this.accel = accel;
        this.accelValid = accelValid;
        this.mag = mag;
        this.magValid = magValid;
        this.gyro = gyro;
        this.gyroValid = gyroValid;
        this.pressure = pressure;
        this.pressureValid = pressureValid;
        this.temperature = temperature;
        this.temperatureValid = temperatureValid;
    }

C 样本结构:


typedef struct {
  double time;
  double accel[3];
  bool accelValid;
  double mag[3];
  bool magValid;
  double gyro[3];
  bool gyroValid;
  double pressure;
  bool pressureValid;
  double temperature;
  bool temperatureValid;
} T_imuDataSample_t;

处理数据的 C 文件:

void HandleImuEvent(T_imuDataSample_t *imuDataSample, int *status,
  double *userHeadingDeg, StrapdownStreaming_RotationMode *currentRotateMode)
{

这是数据从 Java 传递到 C 的地方:

HandleImuEvent(motion.getTcimuEvent(), motion.getStatus(), motions.getUserHeadingDeg(), motions.getRotationMode());

错误的完整跟踪是:

    java.lang.Error: Structure.getFieldOrder() on class com.dataTypes.TCIMUEvent does not provide enough names [0] ([]) to match declared fields [11] ([accel, accelValid, gyro, gyroValid, mag, magValid, pressure, pressureValid, temperature, temperatureValid, time])
        at com.sun.jna.Structure.getFields(Structure.java:1077)
        at com.sun.jna.Structure.deriveLayout(Structure.java:1232)
        at com.sun.jna.Structure.calculateSize(Structure.java:1159)
        at com.sun.jna.Structure.allocateMemory(Structure.java:401)
        at com.sun.jna.Structure.ensureAllocated(Structure.java:377)
        at com.sun.jna.Structure.ensureAllocated(Structure.java:367)
        at com.sun.jna.Structure.size(Structure.java:434)
        at com.sun.jna.Structure.size(Structure.java:1137)
        at com.sun.jna.Native.getNativeSize(Native.java:1354)
        at com.sun.jna.Structure.getNativeSize(Structure.java:2253)
        at com.sun.jna.Structure.getNativeSize(Structure.java:2243)
        at com.sun.jna.Structure.validateField(Structure.java:1209)
        at com.sun.jna.Structure.validateFields(Structure.java:1222)
        at com.sun.jna.Structure.<init>(Structure.java:200)
        at com.sun.jna.Structure.<init>(Structure.java:193)
        at com.sun.jna.Structure.<init>(Structure.java:180)
        at com.sun.jna.Structure.<init>(Structure.java:172)
        at com.dataTypes.Motion.<init>(Motion.java:17)

我觉得我对 JNA 所做的事情有点天真,所以问题在于我对我需要如何传递数据的理解,所以关于这个具体实现的一般建议肯定会帮助我理解使用 JNA 需要哪些步骤. 我已经查看了很多教程,目前正在查看其他答案。如果您需要更多信息或上下文,请给我留言。

4

1 回答 1

0

正如错误所说,您缺少一种GetFieldOrder方法。

文档中

您必须定义 getFieldOrder() 以返回字段名称(字符串)列表,指示字段的正确顺序。在处理 Structure 的多级子类时,必须将当前类中定义的字段添加到超类 getFieldOrder() 提供的列表中。

您还可以使用@Structure.FieldOrder注释来提供字段顺序,而不是定义方法。

于 2020-05-07T12:50:14.253 回答