java事件和监听器，一个类中的多个事件

Question

我是 android/java 新手，目前正在尝试学习自定义事件和侦听器。我目前在下面实现了这个代码，它运行成功。我现在想向 DataRobot 添加另一个事件。当使用analyzeData函数分析某条数据时触发该事件。我想知道是否有人可以告诉我如何在一个类中实现两个事件？我正在使用此事件来触发 AlarmDialog。所以，如果有更好的方法，请告诉我。

/* SmartApp.java */
public class SmartApp extends Activity 
{
    private ConnectDevice cD = new ConnectDevice();
    private DataRobot dR = new DataRobot();
    private DataBuilder dB = new DataBuilder();
    private DataSender dS = new DataSender();
    public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.intro);

    cD.addDataReceivedListener(new DataReceivedListener() {
        @Override
        public void dataReceivedReceived(DataReceivedEvent event) {
            // TODO Auto-generated method stub
            dR.analyzeData(event.getData());
        }
    });
    dR.addDataAnalyzedListener(new DataAnalyzedListener() {
        @Override
        public void dataAnalyzedReceived(DataAnalyzedEvent event) {
            // TODO Auto-generated method stub
            dB.submitData(event.getData());
        }
    });
    dB.addDataBuilderListener(new DataBuilderListener() {
        @Override
        public void dataBuilderReceived(DataBuilderEvent event) {
            // TODO Auto-generated method stub
            dS.sendData(event.getData());
        }
    });
      }
}  

---

/* DataRobot.java */
public class DataRobot {
    /* This class is for analyzing the data */
    private List _listeners = new ArrayList();
    private String data;
    public boolean analyzeData(String temp) {
        /* Analyze the data
         * This function analyzes the data, as explained in the OP
         * This function fires the analyzed data event when finished
             * analyzing the data.
         */
        data = temp;
        fireDataAnalyzedEvent(data); // this fires the dataanalyzedevent
        return true; //for now this will always return true
    }

    public synchronized void addDataAnalyzedListener(DataAnalyzedListener listener) {
        _listeners.add(listener);
    }
    public synchronized void removeDataAnalyzedListener(DataAnalyzedListener listener) {
        _listeners.remove(listener);
    }
    private synchronized void fireDataAnalyzedEvent(String temp) {
        DataAnalyzedEvent dRE = new DataAnalyzedEvent(this, temp);
        Iterator listeners = _listeners.iterator();
        while(listeners.hasNext()) {
            ((DataAnalyzedListener)listeners.next()).dataAnalyzedReceived(dRE);
        }
    }
    public interface DataAnalyzedListener {
        public void dataAnalyzedReceived(DataAnalyzedEvent event);
    }
}  

---

/* DataReceivedEvent.java */
public class DataReceivedEvent extends EventObject{
    private String data;
    public DataReceivedEvent(Object source, String temp) {
        super(source);
        // TODO Auto-generated constructor stub
        data = temp;
    }
    public String getData() {
            // this function is just an accessor function
        return data;
    }
}  

---

/* DataAnalyzedEvent.java */
public class DataAnalyzedEvent extends EventObject{
    private String data;
    public DataAnalyzedEvent(Object source, String temp) {
        super(source);
        // TODO Auto-generated constructor stub
        data = temp;
    }
    public String getData() {
            // this function is just an accessor function
        return data;
    }
}  

Answer 1

我会在 Android 中重新设计。使用服务并注册它以接收具有特定操作类型的 Intent。这样看：意图是你的事件。 Intent Filter 是您的 Intent 映射，事件管理器是通过调用 context.startActivity(Intent) 或通过广播 Intent (pub/sub eventing) 这就是 Android 方式。

Answer 2

如何添加第二个事件取决于这两个事件是否相关。如果一个对象想要同时监听这两个事件，那么只需在DataAnalyzedListener 接口中添加另一个方法即可。

另一种情况是事件不相关并且对象想要订阅一个事件或另一个。在这种情况下，您需要创建两个单独的接口并拥有两个侦听器列表。

其他评论：

使用参数化列表而不是裸类型，您不需要强制转换对象。 您也可以使用 foreach 循环而不是直接获取迭代器。

private List<DataAnalyzedListener> _listeners = new ArrayList<DataAnalyzedListener>();

for (DataAnalyzedListener listener : _listeners) {
  listener.dataAnalyzedReceived(dRE);
}