调用另一个类方法时发生java错误

Question

我正在尝试运行publish（）方法类侦听器

但每当发生错误时。通过创建accessListener var = new Listener (); var.publish ()。他要求在Listener{}找一个建筑工人。使公共侦听器（）{}留空。我可以在Listener中调用System.out.printl ("blabla")，但是publish（）不能

可能是因为Listener{}中的方法publish ()使用了connectionDetails，我可能必须将其传递给构造函数

将有助于从ActionListener/Connect()调用Publish()

类侦听器：

package org.eclipse.paho.安卓.service.sample; import 安卓.content.Context; import 安卓.content.Intent; import 安卓.util.Log; import 安卓.view.MenuItem; import 安卓.view.MenuItem.OnMenuItemClickListener; import 安卓.widget.CheckBox; import 安卓.widget.EditText; import 安卓.widget.RadioGroup; import 安卓.widget.TextView; import org.eclipse.paho.安卓.service.MqttAndroidClient; import org.eclipse.paho.安卓.service.sample.ActionListener.Action; import org.eclipse.paho.安卓.service.sample.Connection.ConnectionStatus; import org.eclipse.paho.client.mqttv3.MqttException; import org.eclipse.paho.client.mqttv3.MqttSecurityException; import java.io.IOException; import java.io.InputStream; import java.util.HashMap; import java.util.Map.Entry; import java.util.logging.LogManager; /** * Deals with actions performed in the {@link ClientConnections} activity * and the {@link ConnectionDetails} activity and associated fragments * */ public class Listener implements OnMenuItemClickListener { /** The handle to a {@link Connection} object which contains the {@link MqttAndroidClient} associated with this object **/ private String clientHandle = null; /** {@link ConnectionDetails} reference used to perform some actions**/ private ConnectionDetails connectionDetails = null; /** {@link ClientConnections} reference used to perform some actions**/ private ClientConnections clientConnections = null; /** {@link Context} used to load and format strings **/ private Context context = null; /** Whether Paho is logging is enabled**/ static boolean logging = false; /** * Constructs a listener object for use with {@link ConnectionDetails} activity and * associated fragments. * @param connectionDetails The instance of {@link ConnectionDetails} * @param clientHandle The handle to the client that the actions are to be performed on */ public Listener(ConnectionDetails connectionDetails, String clientHandle) { this.connectionDetails = connectionDetails; this.clientHandle = clientHandle; context = connectionDetails; } /** * Constructs a listener object for use with {@link ClientConnections} activity. * @param clientConnections */ public Listener(ClientConnections clientConnections) { this.clientConnections = clientConnections; context = this.clientConnections; } public Listener( ) { } /** * Perform the needed action required based on the button that * the user has clicked. * * @param item The menu item that was clicked * @return If there is anymore processing to be done * */ @Override public boolean onMenuItemClick(MenuItem item) { int id = item.getItemId(); switch (id) { case R.id.publish : publish(); break; case R.id.subscribe : subscribe(); break; } return false; } /** * Publish the message the user has specified */ public void publish() { String topic = ((EditText)connectionDetails.findViewById(R.id.lastWillTopic)) .getText().toString(); String message = ((EditText) connectionDetails.findViewById(R.id.lastWill)).getText() .toString(); RadioGroup radio = (RadioGroup) connectionDetails.findViewById(R.id.qosRadio); int checked = radio.getCheckedRadioButtonId(); int qos = ActivityConstants.defaultQos; switch (checked) { case R.id.qos0 : qos = 0; break; case R.id.qos1 : qos = 1; break; case R.id.qos2 : qos = 2; break; } boolean retained = ((CheckBox) connectionDetails.findViewById(R.id.retained)) .isChecked(); String[] args = new String[2]; args[0] = message; args[1] = topic+";qos:"+qos+";retained:"+retained; try { Connections.getInstance(context).getConnection(clientHandle).getClient() .publish(topic, message.getBytes(), qos, retained, null, new ActionListener(context, Action.PUBLISH, clientHandle, args)); } catch (MqttSecurityException e) { Log.e(this.getClass().getCanonicalName(), "Failed to publish a messged from the client with the handle " + clientHandle, e); } catch (MqttException e) { Log.e(this.getClass().getCanonicalName(), "Failed to publish a messged from the client with the handle " + clientHandle, e); } } }