使用线程缓慢的Android Modbus连接

Question

应用程序的功能是连接PLC。我在PLC上使用Modbus服务器，在Android应用程序中使用EasyModbus客户端。如果应用程序第一次连接失败，尝试再次连接大约需要2-3分钟。它在主线程上正常运行，但当我将它移动到单独的线程时，问题就会出现。

我尝试更改连接超时，但没有结果。

public void connect() {
Thread thread = new Thread(new Runnable() {
@Override
public void run() {
while(!connected) {
ModbusClient modbusClient = new ModbusClient("192.168.0.1", 502);
modbusClient.setConnectionTimeout(30);
try {
Log.e(TAG, "Try connecting to port: " + 502;
modbusClient.Connect();
connected = true;
} catch (Exception e) {
e.printStackTrace();
}
}
}
});
thread.start();
}

日志：

Try connecting to port: 502
W/System: A resource failed to call close. 
W/System.err: java.net.ConnectException: failed to connect to /192.168.21.136 (port 1201) from /:: (port 46369): connect failed: ETIMEDOUT (Connection timed out)
W/System.err:     at libcore.io.IoBridge.connect(IoBridge.java:142)
W/System.err:     at java.net.PlainSocketImpl.socketConnect(PlainSocketImpl.java:142)
W/System.err:     at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:390)
W/System.err:     at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:230)
W/System.err:     at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:212)
W/System.err:     at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:436)
at java.net.Socket.connect(Socket.java:621)
W/System.err:     at java.net.Socket.connect(Socket.java:570)
W/System.err:     at java.net.Socket.<init>(Socket.java:450)
W/System.err:     at java.net.Socket.<init>(Socket.java:218)
W/System.err:     at de.re.easymodbus.modbusclient.ModbusClient.Connect(ModbusClient.java:88)
W/System.err:     at com.example.roseoilproduction.MainActivity$1.run(MainActivity.java:101)
W/System.err:     at java.lang.Thread.run(Thread.java:923)
W/System.err: Caused by: android.system.ErrnoException: connect failed: ETIMEDOUT (Connection timed out)
W/System.err:     at libcore.io.Linux.connect(Native Method)
W/System.err:     at libcore.io.ForwardingOs.connect(ForwardingOs.java:94)
at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:138)
W/System.err:     at libcore.io.ForwardingOs.connect(ForwardingOs.java:94)
at libcore.io.IoBridge.connectErrno(IoBridge.java:156)
at libcore.io.IoBridge.connect(IoBridge.java:134)
... 12 more

Answer 1

记住线程是如何工作的之后，我只添加了一个计时器，每隔x秒执行一次线程：

Timer timer = new Timer();
timer.schedule(new TimerTask()
{
@Override
public void run()
{
connect();
}
}, 0, 1000);