Java 密码框无法显示的问题

tangqing24680 2018-12-05 10:24:02



package com.src.self;



import java.awt.*;



import javax.swing.JButton;

import javax.swing.JLabel;

import javax.swing.JTextField;

import javax.swing.JPasswordField;

import javax.swing.JFrame;

import javax.swing.JPanel;

import javax.swing.UIManager;



public class LoginFrame {

	//添加组件的方法

	public void addComponentsToPane(Container pane) {

		JButton buttonOk,buttonCancel;

		

		JLabel labelName,labelPassword;//账户名和密码标签足

		JTextField textFieldName;

		JPasswordField textFieldPwd;

		

		//创建一个顶部面板

		JPanel topPane=new JPanel();

		topPane.setLayout(new GridBagLayout());

		

		//创建一个底部面板

		JPanel bottomPane=new JPanel();

		FlowLayout flowLayout=new FlowLayout();

		flowLayout.setHgap(20);

		flowLayout.setVgap(10);

		bottomPane.setLayout(flowLayout);

		

		//标签账户

		GridBagConstraints conLabelName=new GridBagConstraints();

		conLabelName.fill=GridBagConstraints.NONE;

		labelName=new JLabel("账户：");

		conLabelName.weightx=0.2;

		conLabelName.gridx=0;

		conLabelName.gridy=0;

		conLabelName.anchor=GridBagConstraints.LINE_END;

		topPane.add(labelName,conLabelName);

		

		//账户文本框

		GridBagConstraints conTextFieldName=new GridBagConstraints();

		conTextFieldName.fill=GridBagConstraints.HORIZONTAL;

		textFieldName=new JTextField();

		conTextFieldName.weightx=0.8;

		conTextFieldName.weighty=0.5;

		conTextFieldName.gridx=1;

		conTextFieldName.gridy=0;

		conTextFieldName.insets=new Insets(10, 0, 10, 20);

		topPane.add(textFieldName,conTextFieldName);

		

		//标签密码

		GridBagConstraints conLabelPassword=new GridBagConstraints();

		conLabelPassword.fill=GridBagConstraints.NONE;

		labelPassword=new JLabel("密码：");

		conLabelPassword.gridx=0;

		conLabelPassword.gridy=1;

		conLabelPassword.anchor=GridBagConstraints.LINE_END;

		topPane.add(labelPassword,conLabelPassword);

		

		//密码框

		GridBagConstraints conTextFieldPwd=new GridBagConstraints();

		conTextFieldName.fill=GridBagConstraints.HORIZONTAL;

		textFieldPwd=new JPasswordField("");

		conTextFieldPwd.weighty=0.5;

		conTextFieldPwd.gridx=1;

		conTextFieldPwd.gridy=1;

		conTextFieldPwd.insets=new Insets(0, 0, 0, 20);

		topPane.add(textFieldPwd,conTextFieldPwd);

		

		//添加确定取消面板

		buttonOk=new JButton("确定");

		buttonCancel=new JButton("取消");

		

		bottomPane.add(buttonOk);

		bottomPane.add(buttonCancel);

		pane.add(topPane,BorderLayout.CENTER);

		pane.add(bottomPane,BorderLayout.PAGE_END);

		

	}

	private void createAndShowGUI() {

		JFrame frame=new JFrame("LoginFrame");

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		addComponentsToPane(frame.getContentPane());

		frame.pack();

		frame.setVisible(true);

	}

	

	public static void main(String[] args) {

		javax.swing.SwingUtilities.invokeLater(new Runnable() {

			

			@Override

			public void run() {

				// TODO Auto-generated method stub

				UIManager.put("swing.boldMetal", Boolean.FALSE);//关闭粗体字

				new LoginFrame().createAndShowGUI();

			}

		});

	}

	

}

运行的时候，密码框怎么会这样，大神们，帮忙解答下！！！

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qq_39936465 2018-12-05

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textFieldPwd=new JPasswordField("");你JPasswordField设置为空，所以显示不了。 JPasswordField的构造 JPasswordField() JPasswordField(String text) JPasswordField(int columns) JPasswordField(String text, int columns) text: 默认显示的文本 columns: 用来计算首选宽度的列数；如果列设置为 0，则首选宽度将是组件实现的自然结果修改为 textFieldPwd=new JPasswordField(12);