Java 入门图形用户界面设计之事件处理上

java程序设计 图形用户界面 【七】事件处理上

事件处理

事件和监听器

事件：表示一个对象发生状态变化

监听器：不断地监听事件的变化，并根据这些事件进行相应地处理

事件类 eventobject类

eventobject类的定义格式

public class eventobject extends object implements rializable{public eventobject(object source){// 构造一个发生事件的对象}public object getsource(){// 返回一个事件对象}public string tostring(){// 得到信息}}

java事件处理流程

窗体事件

windowlistener是专门处理窗体事件的监听接口

方法作用void windowactivated(windowevent e)将窗口变为活动窗口时触发void windowdeactivated(windowevent e)将窗口变为不活动窗口时触发void windowclod(windowevent e)当窗口被关闭时触发void windowclosing(windowevent e)当窗口正在关闭时触发void windowiconified(windowevent e)窗口最小化时触发void windowdeiconified(windowevent e)窗口从最小化恢复到正常状态时触发void windowopened(windowevent e)窗口打开时触发

实现windowlistener

import java.awt.event.windowevent;import java.awt.event.windowlistener;public clas测智商的10个智力题s windoweventhandle implements windowlistener {    @override    public void windowactivated(windowevent e) {        system.out.println("窗口被选中");    }    @override    public void windowclod(windowevent e) {        system.out.println("窗口被关闭");    }    @override    public void windowclosing(windowevent e) {        system.out.println("窗口关闭");    }    @override    public void windowdeactivated(windowevent e) {        system.out.println("取消窗口选中");    }    @override    public void windowdeiconified(windowevent e) {        system.out.println("窗口从最小化恢复");    }    @override    public void windowiconified(windowevent e) {        system.out.println("窗口最小化");    }    @override    public void windowopened(windowevent e) {        system.out.println("窗口被打开");    }}

在窗体上注册事件监听器

import javax.swing.*;import java.awt.*;public class hello {    public static void main(string[] args) {        jframe frame = new jframe("一");        frame.addwindowlistener(new windoweventhandle后悔的一件事作文());        frame.tsize(500,300);        frame.tbackground(color.blue);        frame.tlocation(500,500);        frame.tvisible(true);    }}

监听适配器

方便用户进行事件处理的实现。以windowadapter为例，用户只要继承了此类，就可以根据自己的需要覆写方法，如果现在只关心窗口关闭方法，则只在子类中覆写windowclosing()方法即可

通过windowadapter实现监听

import java.awt.event.windowadapter;import java.awt.event.windowevent;public class windoweventhandle extends windowadapter {    @override    public void windowclosing(windowevent e) {        super.windowclosing(e);        system.out.println("窗口关闭");        system.exit(1);    }}

而在窗体操作的代码中，直接使用以上的监听器类即可

import javax.swing.*;import java.awt.*;public class hello {    public static void main(string[] args) {        jframe frame = new jframe("一");        frame.addwindowlistener(new windoweventhandle());        frame.tsize(500,300);        frame.tbackground(color.blue);        frame.tlocation(500,500);        frame.tvisible(true);    }}

使用匿名内部类

import javax.swing.*;import java.awt.*;import java.awt.event.windowevent;public class hello {    public static void main(string[] args) {        jframe frame = new jframe("一");        frame.addwindowl能源动力专业istener(new windoweventhandle(){            @override            public void windowclosing(windowevent e) {                super.windowclosing(e);                system.exit(1);            } 技术英文       });        frame.tsize(500,300);        frame.tbackground(color.blue);        frame.tlocation(500,500);        frame.恭喜英文tvisible(true);    }}

如果现在使用适配器操作类，则直接编写匿名内部类就可以减少监听类的定义

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