I try to create a socket client connection to a python server like this, but it throwss me an error. This is triggered via a button, which works. The server is running on a RPi, but that's not the problem since a Python client works on my PC.
try {
Socket s = new Socket("192.168.178.43", 24069);
InputStreamReader streamReader = new InputStreamReader(s.getInputStream());
BufferedReader reader = new BufferedReader(streamReader);
String advice = reader.readLine();
reader.close();
} catch (UnknownHostException e) {
System.err.println("Unknown Host.");
// System.exit(1);
} catch (IOException e) {
System.err.println("Couldn't get I/O for "
+ "the connection.");
System.err.println(e);
// System.exit(1);
}
Stacktrace:
java.lang.IllegalStateException: Could not execute method of the activity
at android.view.View$1.onClick(View.java:3823)
at android.view.View.performClick(View.java:4438)
at android.view.View$PerformClick.run(View.java:18422)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at android.view.View$1.onClick(View.java:3818)
at android.view.View.performClick(View.java:4438)
at android.view.View$PerformClick.run(View.java:18422)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
Caused by: android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1145)
at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:84)
at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
at libcore.io.IoBridge.connect(IoBridge.java:112)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.Socket.startupSocket(Socket.java:567)
at java.net.Socket.tryAllAddresses(Socket.java:128)
at java.net.Socket.<init>(Socket.java:178)
at java.net.Socket.<init>(Socket.java:150)
at com.example.app.MainActivity.sendMessage(MainActivity.java:65)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at android.view.View$1.onClick(View.java:3818)
at android.view.View.performClick(View.java:4438)
at android.view.View$PerformClick.run(View.java:18422)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5017)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
at dalvik.system.NativeStart.main(Native Method)
you can't do any long time process on the Main UI thread the reason for that to avoid the crash of your App if your operation failed
try to create new thread and do your work inside of it and if u want to pass any result to the UI u cant use
View.Post()
or
context.runOnUiThread()
this is an example of what you can do or you can use asynctask instead
new Thread(new Runnable() {
public void run() {
try {
Socket s = new Socket("192.168.178.43", 24069);
InputStreamReader streamReader = new InputStreamReader(s.getInputStream());
BufferedReader reader = new BufferedReader(streamReader);
String advice = reader.readLine();
reader.close();
} catch (UnknownHostException e) {
System.err.println("Unknown Host.");
// System.exit(1);
} catch (IOException e) {
System.err.println("Couldn't get I/O for "
+ "the connection.");
System.err.println(e);
// System.exit(1);
}
}
}).start();
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