巧用JPopupMenu（一）

最新推荐文章于 2020-09-08 20:02:51 发布

dotnetguy

最新推荐文章于 2020-09-08 20:02:51 发布

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分类专栏： J2EE专栏文章标签： import jcomponent string swing 开发工具 list

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JPopupMenu是对于Swing开发者是在熟悉不过的组件了，不过大部分人只将其作为右击弹出菜单使用，其实JPopupMenu还可以有很多用途，可以说只要是需要弹出式效果的都可以用其实现。例如我们用开发工具输入import java.util.当输入“.”时会自动弹出提示框选项，以下的小程序展示了这样的效果：

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Point;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;

import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPopupMenu;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingConstants;

public class PopupTip extends JFrame {
    String[] messages = new String[] {
                        "getNetworkFromTWaver",
                        "getTreeFromTWaver",
                        "getTableFromTWaver",
                        "getPropertySheetFromTWaver",
                        "getTreeTableFromTWaver",
                        "getChartFromTWaver",
                        "getRPCFromTWaver",
                        "getGUIFrameworkFromTWaver",
                        "getFantasticIdeaFromTWaver",
    };

    JLabel label = new JLabel("TWaver make everything easy!");
    JList list = new JList(messages);
    JComponent tip = new JScrollPane(list);
    JTextArea text = new JTextArea();
    JPopupMenu popup = new JPopupMenu();

    public PopupTip() {
    super(" www.servasoft.com ");
    this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.getContentPane().setLayout(new BorderLayout());
        this.getContentPane().add(new JScrollPane(text), BorderLayout.CENTER);

        this.tip.setPreferredSize(new Dimension(400, 100));
        this.label.setForeground(Color.BLUE);
        this.label.setHorizontalAlignment(SwingConstants.CENTER);
    this.popup.setLayout(new BorderLayout());
        this.popup.add(label, BorderLayout.NORTH);
        this.popup.add(tip, BorderLayout.CENTER);

        this.text.setBackground(Color.BLACK);
       this.text.setForeground(Color.GREEN);
        this.text.setCaretColor(Color.WHITE);

        this.text.addKeyListener(new KeyAdapter() {
            public void keyReleased(KeyEvent e) {
            if(popup.isShowing()){
              popup.setVisible(false);
            }else if (e.getKeyCode() == KeyEvent.VK_PERIOD){
                    Point point = text.getCaret().getMagicCaretPosition();
                    if(point != null){
                    popup.show(text, point.x, point.y);
                    }
                    text.requestFocus();
            }
            }
        });
    }

    public static void main(String[] args) {
        PopupTip ui = new PopupTip();
        ui.setSize(400, 200);
        ui.show();
    }
}