desc:水印显示不由气体主导，无气体时，也应该显示时间

app/src/main/java/com/yinuo/safetywatcher/watcher/port/GasPortUtils.kt

@@ -7,6 +7,7 @@ import com.yinuo.safetywatcher.watcher.port.cmd.CMD
 import com.yinuo.safetywatcher.watcher.port.cmd.CMD.Companion.buildSensorRangeCmd
 import com.yinuo.safetywatcher.watcher.port.cmd.CMD.Companion.buildSwitchSensorCmd
 import com.yinuo.safetywatcher.watcher.port.cmd.CalibrationCmd
+import org.easydarwin.TxtOverlay
 
 object GasPortUtils {
     private const val BAUD_RATE = 9600
@@ -40,6 +41,7 @@ object GasPortUtils {
     fun initPort() {
         openPorts()
         readGasMsg()
+        TxtOverlay.startShow(null)
     }
 
     private fun openPorts() {

library-push/src/main/java/org/easydarwin/TxtOverlay.kt

@@ -64,8 +64,10 @@ object TxtOverlay {
     private val gasMap = ConcurrentHashMap<String, Gas>()
 
     // 外部调用，设置待显示水印文字
-    fun startShow(gas: Gas) {
-        gasMap[gas.gasName] = gas
+    fun startShow(gas: Gas?) {
+        gas?.let {
+            gasMap[it.gasName] = it
+        }
         if (!looping) {
             looping = true
             GlobalScope.launch(Dispatchers.IO) {