error on connecting gazebo with android app [closed]

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Hi

We have an Android application to control a robot. We don't have a robot so we need to work with the simulator. We made a program where the usb_cam sends messages to the tablet. We started a rosmaster for this with roscore. This works perfectly. Now we want to connect with the gazebo simulator but the moment our program makes a node to connect with the rosmaster of the simulator it crashes. We only run the gazebo simulator without a roscore since the simulator starts a master itself.

05-18 14:41:31.240: E/UpdatePublisherRunnable(4990): java.lang.RuntimeException: java.net.ConnectException: failed to connect to /192.168.1.103 (port 35072) after 60000ms: isConnected failed: ECONNREFUSED (Connection refused)

05-18 14:41:42.310: E/AndroidRuntime(4990): java.lang.NullPointerException
05-18 14:41:42.310: E/AndroidRuntime(4990):     at org.ros.time.ClockTopicTimeProvider$1.onNewMessage(ClockTopicTimeProvider.java:45)
05-18 14:41:42.310: E/AndroidRuntime(4990):     at org.ros.time.ClockTopicTimeProvider$1.onNewMessage(ClockTopicTimeProvider.java:42)
05-18 14:41:42.310: E/AndroidRuntime(4990):     at org.ros.internal.transport.IncomingMessageQueue$Dispatcher$1.run(IncomingMessageQueue.java:77)
05-18 14:41:42.310: E/AndroidRuntime(4990):     at org.ros.internal.transport.IncomingMessageQueue$Dispatcher$1.run(IncomingMessageQueue.java:74)
05-18 14:41:42.310: E/AndroidRuntime(4990):     at org.ros.concurrent.ListenerCollection$1.run(ListenerCollection.java:117)
05-18 14:41:42.310: E/AndroidRuntime(4990):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
05-18 14:41:42.310: E/AndroidRuntime(4990):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
05-18 14:41:42.310: E/AndroidRuntime(4990):     at java.lang.Thread.run(Thread.java:856)

Can someone help us?