优化信号获取的实现

app/src/main/java/com/xypower/mpapp/MicroPhotoService.java

@@ -1622,7 +1622,15 @@ public class MicroPhotoService extends Service {
 
             if (ss != null) {
                 int ssVal = -1;
-                List<CellSignalStrength> cellSignalStrengths = ss.getCellSignalStrengths();
+                List<CellSignalStrength> cellSignalStrengths = null;
+                if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.Q) {
+                    cellSignalStrengths = ss.getCellSignalStrengths();
+                } else {
+                    int asu = ss.getGsmSignalStrength();
+                    if (asu != 99) {
+                        ssVal = -113 + 2 * asu;
+                    }
+                }
                 for (CellSignalStrength cellSignalStrength : cellSignalStrengths) {
                     ssVal = cellSignalStrength.getDbm();
                     break;