在Java中创建自定义事件

我想用Java做这样的事情，但是我不知道这样：

当事件“对象1说'你好'”发生时，对象2通过说“你好”来响应该事件。

有人可以给我提示或示例代码吗？

您可能想研究观察者模式。

以下是一些示例代码，可以帮助您入门：

import java.util.*;

// An interface to be implemented by everyone interested in "Hello" events
interface HelloListener {
    void someoneSaidHello();
}

// Someone who says "Hello"
class Initiater {
    private List<HelloListener> listeners = new ArrayList<HelloListener>();

    public void addListener(HelloListener toAdd) {
        listeners.add(toAdd);
    }

    public void sayHello() {
        System.out.println("Hello!!");

        // Notify everybody that may be interested.
        for (HelloListener hl : listeners)
            hl.someoneSaidHello();
    }
}

// Someone interested in "Hello" events
class Responder implements HelloListener {
    @Override
    public void someoneSaidHello() {
        System.out.println("Hello there...");
    }
}

class Test {
    public static void main(String[] args) {
        Initiater initiater = new Initiater();
        Responder responder = new Responder();

        initiater.addListener(responder);

        initiater.sayHello();  // Prints "Hello!!!" and "Hello there..."
    }
}

相关文章：Java：创建自定义事件

您想要的是观察者模式的实现。您可以完全自己做，也可以使用Java类，例如java.util.Observerandjava.util.Observable

您可能希望通过3种不同的方式进行设置：

1. Thrower 代替 Catcher
2. Catcher 代替 Thrower
3. Thrower和Catcher内部在这个例子中另一个类的Test

我正在使用的GITHUB示例示例默认值为选项3，要尝试其他选项，只需取消注释Optional要成为主类的“”代码块的注释，然后将该类设置为文件中的${Main-Class}变量build.xml：

抛出边码所需的4件事：

import java.util.*;//import of java.util.event

//Declaration of the event's interface type, OR import of the interface,
//OR declared somewhere else in the package
interface ThrowListener {
    public void Catch();
}
/*_____________________________________________________________*/class Thrower {
//list of catchers & corresponding function to add/remove them in the list
    List<ThrowListener> listeners = new ArrayList<ThrowListener>();
    public void addThrowListener(ThrowListener toAdd){ listeners.add(toAdd); }
    //Set of functions that Throw Events.
        public void Throw(){ for (ThrowListener hl : listeners) hl.Catch();
            System.out.println("Something thrown");
        }
////Optional: 2 things to send events to a class that is a member of the current class
. . . go to github link to see this code . . .
}

类文件中需要2件事来接收来自类的事件

/*_______________________________________________________________*/class Catcher
implements ThrowListener {//implement added to class
//Set of @Override functions that Catch Events
    @Override public void Catch() {
        System.out.println("I caught something!!");
    }
////Optional: 2 things to receive events from a class that is a member of the current class
. . . go to github link to see this code . . .
}

以下内容并不完全相同，但很相似，我正在寻找一个片段来添加对接口方法的调用，但是发现了这个问题，所以我决定为那些像我这样搜索它的人添加这个片段。 ：

 public class MyClass
 {
        //... class code goes here

        public interface DataLoadFinishedListener {
            public void onDataLoadFinishedListener(int data_type);
        }

        private DataLoadFinishedListener m_lDataLoadFinished;

        public void setDataLoadFinishedListener(DataLoadFinishedListener dlf){
            this.m_lDataLoadFinished = dlf;
        }



        private void someOtherMethodOfMyClass()
        {
            m_lDataLoadFinished.onDataLoadFinishedListener(1);
        }    
    }

用法如下：

myClassObj.setDataLoadFinishedListener(new MyClass.DataLoadFinishedListener() {
            @Override
            public void onDataLoadFinishedListener(int data_type) {
                }
            });