【发布时间】：2021-04-15 17:02:56
【问题描述】：
我是 xamarin 的新手。 为 ProDVX android 8.1.0 开发应用程序来切换 LED 灯 我正在关注一个用 java 编写的示例。
package android_serialport_api;
import android.util.Log;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
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 = "chmod 666 " + device.getAbsolutePath() + "\n"
+ "exit\n";
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 = open(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 FileInputStream getFileInputStream() {
return mFileInputStream;
}
public FileOutputStream getFileOutputStream() {
return mFileOutputStream;
}
// JNI
private native static FileDescriptor open(String path, int baudrate, int flags);
public native void close();
static {
System.loadLibrary("serial_port");
}
}
现在调用这些函数来切换 LED
public void AllGreenOn() { //All Green the lights
try {
sp = new SerialPort(new File("/dev/ttyS1"), 115200, 0);
} catch (IOException e) {
e.printStackTrace();
}
new Thread(new Runnable() {
@Override
public void run() {
if (lock == null) {
System.out.println("lock = null");
} else {
try {
synchronized (lock) {
out = sp.getFileOutputStream();
AllGOnLamps();
out.close();
sp.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
}).run();
}
private void AllGOnLamps() throws IOException { //All the Green lights
int num1 = 0x55;
int num2 = 0xaa;
int numL = 0xfb;
int numR = 0;
int numB = 0;
int numG = 0x70;
int num7 = 0x88;
out.write(intToByteArray(num1));
out.write(intToByteArray(num2));
for (int i = 0; i < 52; i++) {
out.write(intToByteArray(numL));
out.write(intToByteArray(numB));
out.write(intToByteArray(numR));
out.write(intToByteArray(numG));
}
out.write(intToByteArray(num7));
}
我正在 c# 中尝试这个，我的代码是
public class SerialPort
{
private Java.IO.FileDescriptor mFd;
private Java.IO.FileInputStream mFileInputStream;
private Java.IO.FileOutputStream mFileOutputStream;
//[System.Runtime.InteropServices.DllImport("serial_port.so")]
//private static extern Java.IO.FileDescriptor Open(String path, int baudrate, int flags);
public SerialPort(Java.IO.File device, int baudrate, int flags)
{
MainActivity.addDebug(" su beging: .....");
if (!device.CanRead() || !device.CanWrite())
{
MainActivity.addDebug("process su started: .....");
Java.Lang.Process su;
su = Java.Lang.Runtime.GetRuntime().Exec("su");
MainActivity.addDebug("process su made: .....");
string cmd = "chmod 666 " + device.AbsolutePath + "\n" + "exit\n";
su.OutputStream.Write(Encoding.ASCII.GetBytes(cmd));
MainActivity.addDebug("chmod 666 written ..... ");
}
mFd = Open(device.AbsolutePath, baudrate, flags);
if (mFd == null)
{
MainActivity.addDebug("mfd made");
throw new Exception();
}
mFileInputStream = new Java.IO.FileInputStream(mFd);
mFileOutputStream = new Java.IO.FileOutputStream(mFd);
}
public Java.IO.FileInputStream getFileInputStream()
{
return mFileInputStream;
}
public Java.IO.FileOutputStream getFileOutputStream()
{
return mFileOutputStream;
}
}
public void AllGreenOn()
{
try
{
sp = new SerialPort(new Java.IO.File("/dev/ttyS1"), 115200, 0);
_out = sp.getFileOutputStream();
AllGOnLamps();
_out.Close();
}
catch (IOException e)
{
}
}
private SerialPort sp;
private Java.IO.FileOutputStream _out = null;
public void AllGOnLamps()
{
int num1 = 0x55;
int num2 = 0xaa;
int numL = 0xfb;
int numR = 0;
int numB = 0;
int numG = 0x70;
int num7 = 0x88;
_out.Write(intToByteArray(num1));
_out.Write(intToByteArray(num2));
MainActivity.addDebug("num1 written ..... ");
for (int i = 0; i < 52; i++)
{
_out.Write(intToByteArray(numL));
_out.Write(intToByteArray(numB));
_out.Write(intToByteArray(numR));
_out.Write(intToByteArray(numG));
}
_out.Write(intToByteArray(num7));
MainActivity.addDebug("num7 written ..... ");
}
现在这里 mFd = Open(device.AbsolutePath, baudrate, flags);导致应用崩溃
我不知道我在哪里做错了。对此的任何建议或替代方案都将受到高度评价。
【问题讨论】：
标签： java c# android visual-studio