java - Android java.lang.IllegalStateException：无法执行活动的方法

Question

您好，我是学习 android 的新手，我正在尝试在学习 Android 的同时制作一个半有用的应用程序（对我自己），我基本上是在获取有用的 Java 代码（ping X，端口扫描）并添加他们到我的应用程序，我无法弄清楚为什么会发生这个错误，我相信这与代码的第 77 行有关，但我想了解它为什么不起作用，以便下次我可以更好地帮助自己。抱歉这个冗长的问题，我不知道什么时候该闭嘴。

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);
    }
}

score 11 · Accepted Answer

这一行抛出一个，在异常链中NPE产生一个：IllegalStateException

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

因为你没有在你的方法中初始化stopPort（或startPort）。onCreate你应该有类似的东西：

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.

score 1 · Accepted Answer

Kind of late reply but still, @Pheonix2105, As mentioned by Reimeus,

EditText startPort, stopPort;

just declares the variables. This does not initialize the values for these declared variables. Hence the value of these variables are currently 'null'.

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

initializes (or in your terms, ties the stopPort to a UI component) the value of stopPort, thereby avoiding the NullPointerException (which in turn causes the IllegalStatementException in your case).

Hope that clarifies your doubt.

score 0 · Accepted Answer

Either

Didn't initialise a variable or
Initialised a variable and overwrote it when you were declaring them

Often people duplicate the same line in anticipation to change one variable name in each line, to try and make it faster for you, but might forget one line, or miss one word change

EditText stopPort;

That is your problem

score 0 · Accepted Answer

I had the same issue:

Just initialize/declare you View fields below these lines in the onCreate Fuction:

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

E.g.

protected void onCreate(Bundle savedInstanceState) 
 {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    bart = (ImageView) findViewById(R.id.bartView);
    homer = (ImageView) findViewById(R.id.homerView);
}

java - Android java.lang.IllegalStateException：无法执行活动的方法

4 回答 4

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