Java AWT | WindowsStateListener-yiteyi-C++库

WindowsStateListener是java的一部分。awt。活动包。它是一个处理窗口状态事件的接口。当与其关联的帧或窗口被图标化或最大化时，此接口返回一个事件。 类的抽象功能 :

null

WindowsStateChanged（WindowEvent e） ：当窗口的状态更改时调用。

下面的程序演示了WindowsStateListener：

处理窗口事件的Java程序

JAVA

                           // Java Program to handle window events                         
                           import                                        java.awt.*;                         
                           import                                        java.awt.event.*;                         
                           import                                        javax.swing.*;                         
                           class                                        listener1                                        extends                                        JFrame                                        implements                                        WindowStateListener {                         
                                                     listener1()                         
                                                     {                         
                                                     super                                        (                                        "main frame"                                        );                         
                                                     setSize(                                        500                                        ,                                        500                                        );                         
            
                                                     // create a sub frame                         
                                                     JFrame f =                                        new                                        JFrame(                                        "sub"                                        );                         
            
                                                     // add window state listener                         
                                                     f.addWindowStateListener(                                        this                                        );                         
            
                                                     // set size of window                         
                                                     f.setSize(                                        200                                        ,                                        200                                        );                         
            
                                                     show();                         
                                                     f.show();                         
                                                     }                         
            
                                                     // if state of window is changed                         
                                                     public                                        void                                        windowStateChanged(WindowEvent e)                         
                                                     {                         
                                                     JOptionPane.showMessageDialog(                                        this                                        ,                                        "window state changed"                                        );                         
                                                     }                         
                                                     // main class                         
                                                     public                                        static                                        void                                        main(String args[])                         
                                                     {                         
                                                     listener1 l =                                        new                                        listener1();                         
                                                     }                         
                           }                         

输出：

图片[1]-Java AWT | WindowsStateListener-yiteyi-C++库

Java程序来处理窗口事件并识别它们 :

JAVA

                           // Java Program to handle window events and identify them                         
                           import                                        java.awt.*;                         
                           import                                        java.awt.event.*;                         
                           import                                        javax.swing.*;                         
                           class                                        listener                                        extends                                        JFrame                                        implements                                        WindowStateListener {                         
                                                     // label                         
                                                     JLabel l;                         
                                                     JLabel l1;                         
            
                                                     listener()                         
                                                     {                         
                                                     super                                        (                                        "main frame"                                        );                         
                                                     setSize(                                        500                                        ,                                        500                                        );                         
            
                                                     // create a sub frame                         
                                                     JFrame f =                                        new                                        JFrame(                                        "sub"                                        );                         
            
                                                     // add window state listener                         
                                                     f.addWindowStateListener(                                        this                                        );                         
            
                                                     // set size of window                         
                                                     f.setSize(                                        200                                        ,                                        200                                        );                         
            
                                                     // create a label                         
                                                     JLabel lo =                                        new                                        JLabel(                                        "old state : "                                        );                         
                                                     JLabel lo1 =                                        new                                        JLabel(                                        "new state : "                                        );                         
            
                                                     l =                                        new                                        JLabel(                                        ""                                        );                         
                                                     l1 =                                        new                                        JLabel(                                        ""                                        );                         
            
                                                     // create a panel                         
                                                     JPanel p =                                        new                                        JPanel();                         
            
                                                     p.add(lo);                         
                                                     p.add(l);                         
                                                     p.add(lo1);                         
                                                     p.add(l1);                         
                                                     add(p);                         
            
                                                     show();                         
                                                     f.show();                         
                                                     }                         
            
                                                     // if state of window is changed                         
                                                     public                                        void                                        windowStateChanged(WindowEvent e)                         
                                                     {                         
                                                     int                                        s = e.getOldState(), s1 = e.getNewState();                         
            
                                                     // for old state                         
                                                     if                                        (s == Frame.ICONIFIED)                         
                                                     l.setText(                                        "window iconified"                                        );                         
            
                                                     if                                        (s == Frame.MAXIMIZED_BOTH)                         
                                                     l.setText(                                        "window maximized horizontally and vertically"                                        );                         
            
                                                     if                                        (s == Frame.MAXIMIZED_HORIZ)                         
                                                     l.setText(                                        "window maximized horizontally"                                        );                         
            
                                                     if                                        (s == Frame.MAXIMIZED_VERT)                         
                                                     l.setText(                                        "window maximized vertically"                                        );                         
            
                                                     if                                        (s == Frame.NORMAL)                         
                                                     l.setText(                                        "window normal"                                        );                         
            
                                                     // for new state                         
            
                                                     if                                        (s1 == Frame.ICONIFIED)                         
                                                     l1.setText(                                        "window iconified"                                        );                         
            
                                                     if                                        (s1 == Frame.MAXIMIZED_BOTH)                         
                                                     l1.setText(                                        "window maximized horizontally and vertically"                                        );                         
            
                                                     if                                        (s1 == Frame.MAXIMIZED_HORIZ)                         
                                                     l1.setText(                                        "window maximized horizontally"                                        );                         
            
                                                     if                                        (s1 == Frame.MAXIMIZED_VERT)                         
                                                     l1.setText(                                        "window maximized vertically"                                        );                         
            
                                                     if                                        (s1 == Frame.NORMAL)                         
                                                     l1.setText(                                        "window normal"                                        );                         
                                                     }                         
            
                                                     // main class                         
                                                     public                                        static                                        void                                        main(String args[])                         
                                                     {                         
                                                     listener l =                                        new                                        listener();                         
                                                     }                         
                           }                         