안드로이드 NDK 질문드립니다.

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기존에 태블릿과 특정단말기간에 시리얼 통신을 해야해서 개발중에문제가 생겨 질문드립니다. 해당 코드는 https://github.com/cepr/android-serialport-api 의api코드를 가져다 썼습니다. 코드를 먼저 보여드리면Serial.h// // Created by TOP102 on 2018-11-19. // #include #ifndef _Included_serialport_enpsystem_com_serial_1connect_Serial_SerialPort #define _Included_serialport_enpsystem_com_serial_1connect_Serial_SerialPort #ifdef __cplusplus extern "C" { #endif /* * Class: android_serialport_api_SerialPort * Method: open * Signature: (Ljava/lang/String;II)Ljava/io/FileDescriptor; */ JNIEXPORT jobject JNICALL Java_serialport_enpsystem_com_serial_1connect_Serial_SerialPort_openserial (JNIEnv *, jclass, jstring, jint, jint); /* * Class: android_serialport_api_SerialPort * Method: close * Signature: ()V */ JNIEXPORT void JNICALL Java_serialport_enpsystem_com_serial_1connect_Serial_SerialPort_closeserial (JNIEnv *, jobject); #ifdef __cplusplus } #endif #endif 2. SerialPort.c/* * Copyright 2009-2011 Cedric Priscal * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include #include #include #include #include #include #include #include "SerialPort.h" static speed_t getBaudrate(jint baudrate) { switch(baudrate) { case 0: return B0; case 50: return B50; case 75: return B75; case 110: return B110; case 134: return B134; case 150: return B150; case 200: return B200; case 300: return B300; case 600: return B600; case 1200: return B1200; case 1800: return B1800; case 2400: return B2400; case 4800: return B4800; case 9600: return B9600; case 19200: return B19200; case 38400: return B38400; case 57600: return B57600; case 115200: return B115200; case 230400: return B230400; case 460800: return B460800; case 500000: return B500000; case 576000: return B576000; case 921600: return B921600; case 1000000: return B1000000; case 1152000: return B1152000; case 1500000: return B1500000; case 2000000: return B2000000; case 2500000: return B2500000; case 3000000: return B3000000; case 3500000: return B3500000; case 4000000: return B4000000; default: return -1; } } /* * Class: cedric_serial_SerialPort * Method: close * Signature: ()V */ JNIEXPORT void JNICALL Java_serialport_enpsystem_com_serial_1connect_Serial_SerialPort_closeserial (JNIEnv *env, jobject thiz) { jclass SerialPortClass = (*env)->GetObjectClass(env, thiz); jclass FileDescriptorClass = (*env)->FindClass(env, "java/io/FileDescriptor"); jfieldID mFdID = (*env)->GetFieldID(env, SerialPortClass, "mFd", "Ljava/io/FileDescriptor;"); jfieldID descriptorID = (*env)->GetFieldID(env, FileDescriptorClass, "descriptor", "I"); jobject mFd = (*env)->GetObjectField(env, thiz, mFdID); jint descriptor = (*env)->GetIntField(env, mFd, descriptorID); close(descriptor); } /* * Class: android_serialport_SerialPort * Method: open * Signature: (Ljava/lang/String;II)Ljava/io/FileDescriptor; * */ JNIEXPORT jobject JNICALL Java_serialport_enpsystem_com_serial_1connect_Serial_SerialPort_openserial (JNIEnv *env, jclass type, jstring path_, jint baudrate, jint flags) { int fd; speed_t speed; jobject mFileDescriptor; /* Check Arguments */ { speed = getBaudrate(baudrate); if(speed == -1) { return NULL; } } /* Opening Device */ { jboolean iscopy; const char *path_utf = (*env)->GetStringUTFChars(env, path_, &iscopy); fd = open(path_utf, O_RDWR | flags); (*env)->ReleaseStringUTFChars(env, path_, path_utf); if (fd == -1) { return NULL; } } /* Configure device */ { struct termios cfg; if (tcgetattr(fd, &cfg)) { close(fd); return NULL; } cfmakeraw(&cfg); cfsetispeed(&cfg, speed); cfsetospeed(&cfg, speed); if (tcsetattr(fd, TCSANOW, &cfg)) { close(fd); /* TODO: throw an exception */ return NULL; } } /* Create a corresponding file descriptor */ { jclass cFileDescriptor = (*env)->FindClass(env, "java/io/FileDescriptor"); jmethodID iFileDescriptor = (*env)->GetMethodID(env, cFileDescriptor, "", "()V"); jfieldID descriptorID = (*env)->GetFieldID(env, cFileDescriptor, "descriptor", "I"); mFileDescriptor = (*env)->NewObject(env, cFileDescriptor, iFileDescriptor); (*env)->SetIntField(env, mFileDescriptor, descriptorID, (jint)fd); } return mFileDescriptor; }3. Android.mk# Copyright (C) 2009 The Android Open Source Project # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. # LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_MODULE := serial_port LOCAL_SRC_FILES := SerialPort.c include $(BUILD_SHARED_LIBRARY) 4. SerialPort.javapackage serialport.enpsystem.com.serial_connect.Serial; import java.io.BufferedReader; import java.io.File; import java.io.FileDescriptor; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.OutputStream; import android.util.Log; public class SerialPort { private static final String TAG = "SerialPort"; /* * Do not remove or rename the field mFd: it is used by native method close(); */ private FileDescriptor mFd; private FileInputStream mFileInputStream; private FileOutputStream mFileOutputStream; public SerialPort(File device, int baudrate, int flags) throws SecurityException, IOException { /* Check access permission */ if (!device.canRead() || !device.canWrite()) { try { /* Missing read/write permission, trying to chmod the file */ Process su; //su = Runtime.getRuntime().exec("/system/bin/su"); String cmd = "ls -al /dev/ttyXRUSB0"; //String cmd2 = "ls"; su = Runtime.getRuntime().exec(cmd); //su = Runtime.getRuntime().exec(cmd2); BufferedReader br = new BufferedReader(new InputStreamReader(su.getInputStream())); String line; while ((line = br.readLine()) != null) { Log.i("RESULT ANDROID LS", line); } /***************************************************************/ /*su = Runtime.getRuntime().exec("/system/bin/su"); String cmd = "chmod 666 " + device.getAbsolutePath() + " " + "exit "; su.getOutputStream().write(cmd.getBytes()); if ((su.waitFor() != 0) || !device.canRead() || !device.canWrite()) { throw new SecurityException(); }*/ } catch (Exception e) { e.printStackTrace(); throw new SecurityException(); } } mFd = openserial(device.getAbsolutePath(), baudrate, flags); if (mFd == null) { Log.e(TAG, "native open returns null"); throw new IOException(); } mFileInputStream = new FileInputStream(mFd); mFileOutputStream = new FileOutputStream(mFd); } // Getters and setters public InputStream getInputStream() { return mFileInputStream; } public OutputStream getOutputStream() { return mFileOutputStream; } /** * @param path * @param baudrate * @param flags * @return */ // JNI public native static FileDescriptor openserial(String path, int baudrate, int flags); public native void closeserial(); static { System.loadLibrary("serial_port"); } }========================여기서 문제가 빌드 후에 자바에서 사용하는 openserial 은 함수 인식이안되며closeserial은 정상적으로 인식이 됩니다.각각 서로다른곳에서 불러오느것이라면 이해가 되지만 같은곳에서 불러오는데 자꾸만 오류나서 지우고 openserial을 새로 생성해보고 함수명도 바꿔봐도 계속 문제가 생기네요

EF · Answer

openserial 함수는 static으로 정의 되어있고 closeserial은 nonstatic으로 되어있네요.

Neve · Answer

ㄴ static을 지우고 처리해봤으나 결과는 같네요..

안드로이드 NDK 질문드립니다.

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