Hello I’m new to learning android and I’m trying to make a semi-useful app

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Asked: June 17, 20262026-06-17T20:43:22+00:00 2026-06-17T20:43:22+00:00

Hello I’m new to learning android and I’m trying to make a semi-useful app

0

Hello I’m new to learning android and I’m trying to make a semi-useful app (to myself) while learning Android, I’m basically at the minute taking useful bits of Java code (ping X, Port Scan) and adding them to my app, I cannot figure out why this error is occurring, I do believe it is to do with Line 77 of the code but I want to learn why it is isn’t working so I can better help myself next time. Sorry for the wordy question, I don’t know when to shut up.

01-25 20:42:42.139: E/AndroidRuntime(1307): FATAL EXCEPTION: main
01-25 20:42:42.139: E/AndroidRuntime(1307): java.lang.IllegalStateException: Could not execute method of the activity
01-25 20:42:42.139: E/AndroidRuntime(1307):     at android.view.View$1.onClick(View.java:3597)
01-25 20:42:42.139: E/AndroidRuntime(1307):     at android.view.View.performClick(View.java:4202)
01-25 20:42:42.139: E/AndroidRuntime(1307):     at android.view.View$PerformClick.run(View.java:17340)
01-25 20:42:42.139: E/AndroidRuntime(1307):     at android.os.Handler.handleCallback(Handler.java:725)
01-25 20:42:42.139: E/AndroidRuntime(1307):     at android.os.Handler.dispatchMessage(Handler.java:92)
01-25 20:42:42.139: E/AndroidRuntime(1307):     at android.os.Looper.loop(Looper.java:137)
01-25 20:42:42.139: E/AndroidRuntime(1307):     at android.app.ActivityThread.main(ActivityThread.java:5191)
01-25 20:42:42.139: E/AndroidRuntime(1307):     at java.lang.reflect.Method.invokeNative(Native Method)
01-25 20:42:42.139: E/AndroidRuntime(1307):     at java.lang.reflect.Method.invoke(Method.java:511)
01-25 20:42:42.139: E/AndroidRuntime(1307):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
01-25 20:42:42.139: E/AndroidRuntime(1307):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
01-25 20:42:42.139: E/AndroidRuntime(1307):     at dalvik.system.NativeStart.main(Native Method)
01-25 20:42:42.139: E/AndroidRuntime(1307): Caused by: java.lang.reflect.InvocationTargetException
01-25 20:42:42.139: E/AndroidRuntime(1307):     at java.lang.reflect.Method.invokeNative(Native Method)
01-25 20:42:42.139: E/AndroidRuntime(1307):     at java.lang.reflect.Method.invoke(Method.java:511)
01-25 20:42:42.139: E/AndroidRuntime(1307):     at android.view.View$1.onClick(View.java:3592)
01-25 20:42:42.139: E/AndroidRuntime(1307):     ... 11 more
01-25 20:42:42.139: E/AndroidRuntime(1307): Caused by: java.lang.NullPointerException
01-25 20:42:42.139: E/AndroidRuntime(1307):     at com.seven.up.MainActivity.OnClickPort(MainActivity.java:77)
01-25 20:42:42.139: E/AndroidRuntime(1307):     ... 14 more
01-25 20:44:42.549: E/MPL-storeload(511): calData from inv_save_mpl_states, size=2
01-25 20:45:39.759: E/InputDispatcher(511): channel '41b55368 com.seven.up/com.seven.up.MainActivity (server)' ~ Channel is unrecoverably broken and will be disposed!
01-25 20:45:50.279: E/AndroidRuntime(1625): FATAL EXCEPTION: main
01-25 20:45:50.279: E/AndroidRuntime(1625): java.lang.IllegalStateException: Could not execute method of the activity
01-25 20:45:50.279: E/AndroidRuntime(1625):     at android.view.View$1.onClick(View.java:3597)
01-25 20:45:50.279: E/AndroidRuntime(1625):     at android.view.View.performClick(View.java:4202)
01-25 20:45:50.279: E/AndroidRuntime(1625):     at android.view.View$PerformClick.run(View.java:17340)
01-25 20:45:50.279: E/AndroidRuntime(1625):     at android.os.Handler.handleCallback(Handler.java:725)
01-25 20:45:50.279: E/AndroidRuntime(1625):     at android.os.Handler.dispatchMessage(Handler.java:92)
01-25 20:45:50.279: E/AndroidRuntime(1625):     at android.os.Looper.loop(Looper.java:137)
01-25 20:45:50.279: E/AndroidRuntime(1625):     at android.app.ActivityThread.main(ActivityThread.java:5191)
01-25 20:45:50.279: E/AndroidRuntime(1625):     at java.lang.reflect.Method.invokeNative(Native Method)
01-25 20:45:50.279: E/AndroidRuntime(1625):     at java.lang.reflect.Method.invoke(Method.java:511)
01-25 20:45:50.279: E/AndroidRuntime(1625):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
01-25 20:45:50.279: E/AndroidRuntime(1625):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
01-25 20:45:50.279: E/AndroidRuntime(1625):     at dalvik.system.NativeStart.main(Native Method)
01-25 20:45:50.279: E/AndroidRuntime(1625): Caused by: java.lang.reflect.InvocationTargetException
01-25 20:45:50.279: E/AndroidRuntime(1625):     at java.lang.reflect.Method.invokeNative(Native Method)
01-25 20:45:50.279: E/AndroidRuntime(1625):     at java.lang.reflect.Method.invoke(Method.java:511)
01-25 20:45:50.279: E/AndroidRuntime(1625):     at android.view.View$1.onClick(View.java:3592)
01-25 20:45:50.279: E/AndroidRuntime(1625):     ... 11 more
01-25 20:45:50.279: E/AndroidRuntime(1625): Caused by: java.lang.NullPointerException
01-25 20:45:50.279: E/AndroidRuntime(1625):     at com.seven.up.MainActivity.OnClickPort(MainActivity.java:78)
01-25 20:45:50.279: E/AndroidRuntime(1625):     ... 14 more
01-25 20:46:32.409: E/InputDispatcher(511): channel '416e8e78 com.seven.up/com.seven.up.MainActivity (server)' ~ Channel is unrecoverably broken and will be disposed!
01-25 20:46:35.449: E/AndroidRuntime(1830): FATAL EXCEPTION: main
01-25 20:46:35.449: E/AndroidRuntime(1830): java.lang.IllegalStateException: Could not execute method of the activity
01-25 20:46:35.449: E/AndroidRuntime(1830):     at android.view.View$1.onClick(View.java:3597)
01-25 20:46:35.449: E/AndroidRuntime(1830):     at android.view.View.performClick(View.java:4202)
01-25 20:46:35.449: E/AndroidRuntime(1830):     at android.view.View$PerformClick.run(View.java:17340)
01-25 20:46:35.449: E/AndroidRuntime(1830):     at android.os.Handler.handleCallback(Handler.java:725)
01-25 20:46:35.449: E/AndroidRuntime(1830):     at android.os.Handler.dispatchMessage(Handler.java:92)
01-25 20:46:35.449: E/AndroidRuntime(1830):     at android.os.Looper.loop(Looper.java:137)
01-25 20:46:35.449: E/AndroidRuntime(1830):     at android.app.ActivityThread.main(ActivityThread.java:5191)
01-25 20:46:35.449: E/AndroidRuntime(1830):     at java.lang.reflect.Method.invokeNative(Native Method)
01-25 20:46:35.449: E/AndroidRuntime(1830):     at java.lang.reflect.Method.invoke(Method.java:511)
01-25 20:46:35.449: E/AndroidRuntime(1830):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
01-25 20:46:35.449: E/AndroidRuntime(1830):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
01-25 20:46:35.449: E/AndroidRuntime(1830):     at dalvik.system.NativeStart.main(Native Method)
01-25 20:46:35.449: E/AndroidRuntime(1830): Caused by: java.lang.reflect.InvocationTargetException
01-25 20:46:35.449: E/AndroidRuntime(1830):     at java.lang.reflect.Method.invokeNative(Native Method)
01-25 20:46:35.449: E/AndroidRuntime(1830):     at java.lang.reflect.Method.invoke(Method.java:511)
01-25 20:46:35.449: E/AndroidRuntime(1830):     at android.view.View$1.onClick(View.java:3592)
01-25 20:46:35.449: E/AndroidRuntime(1830):     ... 11 more
01-25 20:46:35.449: E/AndroidRuntime(1830): Caused by: java.lang.NullPointerException
01-25 20:46:35.449: E/AndroidRuntime(1830):     at com.seven.up.MainActivity.OnClickPort(MainActivity.java:77)
01-25 20:46:35.449: E/AndroidRuntime(1830):     ... 14 more
01-25 20:47:40.119: E/AndroidRuntime(2009): FATAL EXCEPTION: main
01-25 20:47:40.119: E/AndroidRuntime(2009): java.lang.IllegalStateException: Could not execute method of the activity
01-25 20:47:40.119: E/AndroidRuntime(2009):     at android.view.View$1.onClick(View.java:3597)
01-25 20:47:40.119: E/AndroidRuntime(2009):     at android.view.View.performClick(View.java:4202)
01-25 20:47:40.119: E/AndroidRuntime(2009):     at android.view.View$PerformClick.run(View.java:17340)
01-25 20:47:40.119: E/AndroidRuntime(2009):     at android.os.Handler.handleCallback(Handler.java:725)
01-25 20:47:40.119: E/AndroidRuntime(2009):     at android.os.Handler.dispatchMessage(Handler.java:92)
01-25 20:47:40.119: E/AndroidRuntime(2009):     at android.os.Looper.loop(Looper.java:137)
01-25 20:47:40.119: E/AndroidRuntime(2009):     at android.app.ActivityThread.main(ActivityThread.java:5191)
01-25 20:47:40.119: E/AndroidRuntime(2009):     at java.lang.reflect.Method.invokeNative(Native Method)
01-25 20:47:40.119: E/AndroidRuntime(2009):     at java.lang.reflect.Method.invoke(Method.java:511)
01-25 20:47:40.119: E/AndroidRuntime(2009):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
01-25 20:47:40.119: E/AndroidRuntime(2009):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
01-25 20:47:40.119: E/AndroidRuntime(2009):     at dalvik.system.NativeStart.main(Native Method)
01-25 20:47:40.119: E/AndroidRuntime(2009): Caused by: java.lang.reflect.InvocationTargetException
01-25 20:47:40.119: E/AndroidRuntime(2009):     at java.lang.reflect.Method.invokeNative(Native Method)
01-25 20:47:40.119: E/AndroidRuntime(2009):     at java.lang.reflect.Method.invoke(Method.java:511)
01-25 20:47:40.119: E/AndroidRuntime(2009):     at android.view.View$1.onClick(View.java:3592)
01-25 20:47:40.119: E/AndroidRuntime(2009):     ... 11 more
01-25 20:47:40.119: E/AndroidRuntime(2009): Caused by: java.lang.NullPointerException
01-25 20:47:40.119: E/AndroidRuntime(2009):     at com.seven.up.MainActivity.OnClickPort(MainActivity.java:77)
01-25 20:47:40.119: E/AndroidRuntime(2009):     ... 14 more
01-25 20:49:29.979: E/InputDispatcher(511): channel '414e7770 com.seven.up/com.seven.up.MainActivity (server)' ~ Channel is unrecoverably broken and will be disposed!
01-25 20:49:30.149: E/jdwp(2216): Failed sending reply to debugger: Broken pipe
01-25 20:49:41.599: E/MPL-storeload(511): calData from inv_save_mpl_states, size=2
01-25 20:50:12.539: E/InputDispatcher(511): channel '41c0a160 com.seven.up/com.seven.up.MainActivity (server)' ~ Channel is unrecoverably broken and will be disposed!
01-25 20:50:13.629: E/InputManager-JNI(511): An exception was thrown by callback 'interceptKeyBeforeQueueing'.
01-25 20:50:13.629: E/InputManager-JNI(511): java.lang.NullPointerException
01-25 20:50:13.629: E/InputManager-JNI(511):    at com.android.internal.policy.impl.PhoneWindowManager.interceptKeyBeforeQueueing(PhoneWindowManager.java:3948)
01-25 20:50:13.629: E/InputManager-JNI(511):    at com.android.server.wm.InputMonitor.interceptKeyBeforeQueueing(InputMonitor.java:337)
01-25 20:50:13.629: E/InputManager-JNI(511):    at com.android.server.input.InputManagerService.interceptKeyBeforeQueueing(InputManagerService.java:1346)
01-25 20:50:13.629: E/InputManager-JNI(511):    at dalvik.system.NativeStart.run(Native Method)
01-25 20:50:13.899: E/InputManager-JNI(511): An exception was thrown by callback 'interceptKeyBeforeQueueing'.
01-25 20:50:13.899: E/InputManager-JNI(511): java.lang.NullPointerException
01-25 20:50:13.899: E/InputManager-JNI(511):    at com.android.internal.policy.impl.PhoneWindowManager.interceptKeyBeforeQueueing(PhoneWindowManager.java:3948)
01-25 20:50:13.899: E/InputManager-JNI(511):    at com.android.server.wm.InputMonitor.interceptKeyBeforeQueueing(InputMonitor.java:337)
01-25 20:50:13.899: E/InputManager-JNI(511):    at com.android.server.input.InputManagerService.interceptKeyBeforeQueueing(InputManagerService.java:1346)
01-25 20:50:13.899: E/InputManager-JNI(511):    at dalvik.system.NativeStart.run(Native Method)
01-25 20:50:19.759: E/InputDispatcher(511): channel '41419b38 com.seven.up/com.seven.up.MainActivity (server)' ~ Channel is unrecoverably broken and will be disposed!
01-25 20:51:49.459: E/WeatherXmlParser(2522): Couldn't parse Yahoo weather XML
01-25 20:51:49.459: E/WeatherXmlParser(2522): java.lang.NumberFormatException: Invalid float: ""
01-25 20:51:49.459: E/WeatherXmlParser(2522):   at java.lang.StringToReal.invalidReal(StringToReal.java:63)
01-25 20:51:49.459: E/WeatherXmlParser(2522):   at java.lang.StringToReal.parseFloat(StringToReal.java:289)
01-25 20:51:49.459: E/WeatherXmlParser(2522):   at java.lang.Float.parseFloat(Float.java:300)
01-25 20:51:49.459: E/WeatherXmlParser(2522):   at com.cyanogenmod.lockclock.weather.WeatherXmlParser.getFloatForAttribute(WeatherXmlParser.java:86)
01-25 20:51:49.459: E/WeatherXmlParser(2522):   at com.cyanogenmod.lockclock.weather.WeatherXmlParser.parseWeatherResponse(WeatherXmlParser.java:108)
01-25 20:51:49.459: E/WeatherXmlParser(2522):   at com.cyanogenmod.lockclock.weather.WeatherUpdateService$WeatherUpdateTask.doInBackground(WeatherUpdateService.java:210)
01-25 20:51:49.459: E/WeatherXmlParser(2522):   at com.cyanogenmod.lockclock.weather.WeatherUpdateService$WeatherUpdateTask.doInBackground(WeatherUpdateService.java:126)
01-25 20:51:49.459: E/WeatherXmlParser(2522):   at android.os.AsyncTask$2.call(AsyncTask.java:287)
01-25 20:51:49.459: E/WeatherXmlParser(2522):   at java.util.concurrent.FutureTask.run(FutureTask.java:234)
01-25 20:51:49.459: E/WeatherXmlParser(2522):   at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:230)
01-25 20:51:49.459: E/WeatherXmlParser(2522):   at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
01-25 20:51:49.459: E/WeatherXmlParser(2522):   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
01-25 20:51:49.459: E/WeatherXmlParser(2522):   at java.lang.Thread.run(Thread.java:856)
01-25 20:52:24.619: E/MPL-storeload(511): calData from inv_save_mpl_states, size=2
01-25 20:57:07.229: E/AndroidRuntime(2410): FATAL EXCEPTION: main
01-25 20:57:07.229: E/AndroidRuntime(2410): java.lang.IllegalStateException: Could not execute method of the activity
01-25 20:57:07.229: E/AndroidRuntime(2410):     at android.view.View$1.onClick(View.java:3597)
01-25 20:57:07.229: E/AndroidRuntime(2410):     at android.view.View.performClick(View.java:4202)
01-25 20:57:07.229: E/AndroidRuntime(2410):     at android.view.View$PerformClick.run(View.java:17340)
01-25 20:57:07.229: E/AndroidRuntime(2410):     at android.os.Handler.handleCallback(Handler.java:725)
01-25 20:57:07.229: E/AndroidRuntime(2410):     at android.os.Handler.dispatchMessage(Handler.java:92)
01-25 20:57:07.229: E/AndroidRuntime(2410):     at android.os.Looper.loop(Looper.java:137)
01-25 20:57:07.229: E/AndroidRuntime(2410):     at android.app.ActivityThread.main(ActivityThread.java:5191)
01-25 20:57:07.229: E/AndroidRuntime(2410):     at java.lang.reflect.Method.invokeNative(Native Method)
01-25 20:57:07.229: E/AndroidRuntime(2410):     at java.lang.reflect.Method.invoke(Method.java:511)
01-25 20:57:07.229: E/AndroidRuntime(2410):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
01-25 20:57:07.229: E/AndroidRuntime(2410):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
01-25 20:57:07.229: E/AndroidRuntime(2410):     at dalvik.system.NativeStart.main(Native Method)
01-25 20:57:07.229: E/AndroidRuntime(2410): Caused by: java.lang.reflect.InvocationTargetException
01-25 20:57:07.229: E/AndroidRuntime(2410):     at java.lang.reflect.Method.invokeNative(Native Method)
01-25 20:57:07.229: E/AndroidRuntime(2410):     at java.lang.reflect.Method.invoke(Method.java:511)
01-25 20:57:07.229: E/AndroidRuntime(2410):     at android.view.View$1.onClick(View.java:3592)
01-25 20:57:07.229: E/AndroidRuntime(2410):     ... 11 more
01-25 20:57:07.229: E/AndroidRuntime(2410): Caused by: java.lang.NullPointerException
01-25 20:57:07.229: E/AndroidRuntime(2410):     at com.seven.up.MainActivity.OnClickPort(MainActivity.java:77)
01-25 20:57:07.229: E/AndroidRuntime(2410):     ... 14 more
01-25 20:59:12.549: E/AndroidRuntime(3168): FATAL EXCEPTION: main
01-25 20:59:12.549: E/AndroidRuntime(3168): java.lang.IllegalStateException: Could not execute method of the activity
01-25 20:59:12.549: E/AndroidRuntime(3168):     at android.view.View$1.onClick(View.java:3597)
01-25 20:59:12.549: E/AndroidRuntime(3168):     at android.view.View.performClick(View.java:4202)
01-25 20:59:12.549: E/AndroidRuntime(3168):     at android.view.View$PerformClick.run(View.java:17340)
01-25 20:59:12.549: E/AndroidRuntime(3168):     at android.os.Handler.handleCallback(Handler.java:725)
01-25 20:59:12.549: E/AndroidRuntime(3168):     at android.os.Handler.dispatchMessage(Handler.java:92)
01-25 20:59:12.549: E/AndroidRuntime(3168):     at android.os.Looper.loop(Looper.java:137)
01-25 20:59:12.549: E/AndroidRuntime(3168):     at android.app.ActivityThread.main(ActivityThread.java:5191)
01-25 20:59:12.549: E/AndroidRuntime(3168):     at java.lang.reflect.Method.invokeNative(Native Method)
01-25 20:59:12.549: E/AndroidRuntime(3168):     at java.lang.reflect.Method.invoke(Method.java:511)
01-25 20:59:12.549: E/AndroidRuntime(3168):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
01-25 20:59:12.549: E/AndroidRuntime(3168):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
01-25 20:59:12.549: E/AndroidRuntime(3168):     at dalvik.system.NativeStart.main(Native Method)
01-25 20:59:12.549: E/AndroidRuntime(3168): Caused by: java.lang.reflect.InvocationTargetException
01-25 20:59:12.549: E/AndroidRuntime(3168):     at java.lang.reflect.Method.invokeNative(Native Method)
01-25 20:59:12.549: E/AndroidRuntime(3168):     at java.lang.reflect.Method.invoke(Method.java:511)
01-25 20:59:12.549: E/AndroidRuntime(3168):     at android.view.View$1.onClick(View.java:3592)
01-25 20:59:12.549: E/AndroidRuntime(3168):     ... 11 more
01-25 20:59:12.549: E/AndroidRuntime(3168): Caused by: java.lang.NullPointerException
01-25 20:59:12.549: E/AndroidRuntime(3168):     at com.seven.up.MainActivity.OnClickPort(MainActivity.java:76)
01-25 20:59:12.549: E/AndroidRuntime(3168):     ... 14 more
01-25 21:01:13.939: E/MPL-storeload(511): calData from inv_save_mpl_states, size=2

package com.seven.up;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.*;

import android.app.Activity;
import android.os.Bundle;
import android.text.Editable;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends Activity implements OnClickListener {
    EditText ip_address_field;
    TextView scan_out;
    TextView port_results;
    EditText startPort;
    EditText stopPort;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ip_address_field = (EditText) findViewById(R.id.ip_address_field);
        ip_address_field.getText();
        scan_out = (TextView) findViewById(R.id.scan_out);

        Button scan_button = (Button) findViewById(R.id.scan_button);
        scan_button.setOnClickListener(this);
    }

    public void onClick(View v) {
        Editable host = ip_address_field.getText();

        switch (v.getId()) {

        case R.id.scan_button:
            try {
                String pingCmd = "ping -c 5 " + host;
                String pingResult = "";
                Runtime r = Runtime.getRuntime();
                Process p = r.exec(pingCmd);
                BufferedReader in = new BufferedReader(new InputStreamReader(
                        p.getInputStream()));
                String inputLine;
                while ((inputLine = in.readLine()) != null) {
                    System.out.println(inputLine);
                    scan_out.setText(inputLine + "\n" + "\n");
                    pingResult += inputLine;
                    scan_out.setText("/n" + pingResult);
                }
                in.close();
            }// try
            catch (IOException e) {
                System.out.println(e);
            }
            break;

        default:
            break;
        }

    }

    public void OnClickPort(View v) {
        switch (v.getId()) {
        case R.id.button1:

        int startPortRange = Integer.parseInt(startPort.getText().toString());
        int stopPortRange = Integer.parseInt(stopPort.getText().toString());

        for (int i = startPortRange; i <= stopPortRange; i++) {
            try {
                Socket ServerSok = new Socket("192.168.0.1", i);

                Toast.makeText(getApplicationContext(), "Port in use: " + i, Toast.LENGTH_LONG).show();

                ServerSok.close();
            } catch (Exception e) {
            }
            System.out.println("Port not in use: " + i);
        } 
        }
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.activity_main, menu);
        return super.onCreateOptionsMenu(menu);
    }
}

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1 Answer

Editorial Team · Answer 1 · 2026-06-17T20:43:23+00:00

This line is throwing anNPE, producing an IllegalStateException in the exception chain:

int stopPortRange = Integer.parseInt(stopPort.getText().toString());

as you don’t initialize stopPort (or startPort) in your onCreate method. You should have something like:

stopPort = (EditText) findViewById(R.id.stop_port_field);

The statement

EditText stopPort;

simply declares the variable which is null by default. Only instances that have been instantiated can have their methods invoked.

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