【2023】Kotlin教程第三篇 Kotlin进阶第23章 Kotlin与Java Swing图形用户界面编程 23.6 案例：图书库存

末蓝、 2024-03-23 14:30 48阅读 0赞

### 【2023】Kotlin教程 ###

#### 文章目录 ####

*   *  【2023】Kotlin教程
     *   *  第三篇 Kotlin进阶
         *  第23章 Kotlin与Java Swing图形用户界面编程
         *   *  23.6 案例：图书库存

![在这里插入图片描述][707492f2c4fd488086b54048c9357fd5.png_pic_center]

#### 第三篇 Kotlin进阶 ####

#### 第23章 Kotlin与Java Swing图形用户界面编程 ####

Kotlin目前没有自己的图形界面技术。开发人员可以借助于Java图形界面技术实现Kotlin图形界面应用程序。

图形用户界面（Graphical User Interface，简称 GUI）编程对于某种语言来说非常重要。Java的应用主要方向是基于Web浏览器的应用，用户界面主要是HTML、CSS和JavaScript等基于Web的技术，这些介绍要到Java EE阶段才能学习到。而基于Java SE的Swing，事实上它们在实际应用中使用不多。

##### 23.6 案例：图书库存 #####

在实际项目开发中往往数据是从数据库中查询返回的，数据结构有多种形式，采用自定义模型可以接收任何形式的数据。本节将上一节的图书表格示例采用自定义模型重构一下。

![在这里插入图片描述][cab37fbb8c16486eaaf1e3667c2de6d9.png_pic_center]

在进行数据库设计时，数据库中每一个表对应Kotlin实体类，实体类是系统的“人”、“事”、“物”等一些名词，例如图书（Book）就是一个实体类了，实体类Book代码如下：

//图书实体类
    data class Book(
        // 图书编号
        val bookid: String,
        // 图书名称
        val bookname: String,
        // 图书作者
        val author: String,
        // 出版社
        val publisher: String,
        // 出版日期
        val pubtime: String,
        // 库存数量
        val inventory: Int
    )

实体类可以声明为数据类。

由于目前没有介绍数据库编程，本例表格中的数据是从JSON文件Books.json中读取的，Books.json位于项目的db目录中，JSON文件Books.json的内容如下：

[{
        "bookid":"0036","bookname":"高等数学","author":"李放","publisher":"人民邮电出版社","pubtime":"20000812","inventory":1},
    {
        "bookid":"0004","bookname":"FLASH精选","author":"刘扬","publisher":"中国纺织出版社","pubtime":"19990312","inventory":2},
    {
        "bookid":"0026","bookname":"软件工程","author":"牛田","publisher":"经济科学出版社","pubtime":"20000328","inventory":4},
    {
        "bookid":"0015","bookname":"人工智能","author":"周未","publisher":"机械工业出版社","pubtime":"19991223","inventory":3},
    {
        "bookid":"0037","bookname":"南方周末","author":"邓光明","publisher":"南方出版社","pubtime":"20000923","inventory":3},
    {
        "bookid":"0008","bookname":"新概念3","author":"余智","publisher":"外语出版社","pubtime":"19990723","inventory":2},
    {
        "bookid":"0019","bookname":"通讯与网络","author":"欧阳杰","publisher":"机械工业出版社","pubtime":"20000517","inventory":1},
    {
        "bookid":"0014","bookname":"期货分析","author":"孙宝","publisher":"飞鸟出版社","pubtime":"19991122","inventory":3},
    {
        "bookid":"0023","bookname":"经济概论","author":"思佳","publisher":"北京大学出版社","pubtime":"20000819","inventory":3},
    {
        "bookid":"0017","bookname":"计算机理论基础","author":"戴家","publisher":"机械工业出版社","pubtime":"20000218","inventory":4},
    {
        "bookid":"0002","bookname":"汇编语言","author":"李利光","publisher":"北京大学出版社","pubtime":"19980318","inventory":2},
    {
        "bookid":"0033","bookname":"模拟电路","author":"邓英才","publisher":"电子工业出版社","pubtime":"20000527","inventory":2},
    {
        "bookid":"0011","bookname":"南方旅游","author":"王爱国","publisher":"南方出版社","pubtime":"19990930","inventory":2},
    {
        "bookid":"0039","bookname":"黑幕","author":"李仪","publisher":"华光出版社","pubtime":"20000508","inventory":24},
    {
        "bookid":"0001","bookname":"软件工程","author":"戴国强","publisher":"机械工业出版社","pubtime":"19980528","inventory":2},
    {
        "bookid":"0034","bookname":"集邮爱好者","author":"李云","publisher":"人民邮电出版社","pubtime":"20000630","inventory":1},
    {
        "bookid":"0031","bookname":"软件工程","author":"戴志名","publisher":"电子工业出版社","pubtime":"20000324","inventory":3},
    {
        "bookid":"0030","bookname":"数据库及应用","author":"孙家萧","publisher":"清华大学出版社","pubtime":"20000619","inventory":1},
    {
        "bookid":"0024","bookname":"经济与科学","author":"毛波","publisher":"经济科学出版社","pubtime":"20000923","inventory":2},
    {
        "bookid":"0009","bookname":"军事要闻","author":"张强","publisher":"解放军出版社","pubtime":"19990722","inventory":3},
    {
        "bookid":"0003","bookname":"计算机基础","author":"王飞","publisher":"经济科学出版社","pubtime":"19980218","inventory":1},
    {
        "bookid":"0020","bookname":"现代操作系统","author":"王小国","publisher":"机械工业出版社","pubtime":"20010128","inventory":1},
    {
        "bookid":"0025","bookname":"计算机体系结构","author":"方丹","publisher":"机械工业出版社","pubtime":"20000328","inventory":4},
    {
        "bookid":"0010","bookname":"大众生活","author":"许阳","publisher":"电子出版社","pubtime":"19990819","inventory":3},
    {
        "bookid":"0021","bookname":"网络基础","author":"王大尉","publisher":"北京大学出版社","pubtime":"20000617","inventory":1},
    {
        "bookid":"0006","bookname":"世界杯","author":"柳飞","publisher":"世界出版社","pubtime":"19990412","inventory":2},
    {
        "bookid":"0028","bookname":"高级语言程序设计","author":"寇国华","publisher":"清华大学出版社","pubtime":"20000117","inventory":3},
    {
        "bookid":"0038","bookname":"十大旅游胜地","author":"潭晓明","publisher":"南方出版社","pubtime":"20000403","inventory":2},
    {
        "bookid":"0018","bookname":"编译原理","author":"郑键","publisher":"机械工业出版社","pubtime":"20000415","inventory":2},
    {
        "bookid":"0007","bookname":"JAVA程序设计","author":"张余","publisher":"人民邮电出版社","pubtime":"19990613","inventory":1},
    {
        "bookid":"0013","bookname":"幽灵","author":"钱力华","publisher":"华光出版社","pubtime":"19991008","inventory":1},
    {
        "bookid":"0022","bookname":"万紫千红","author":"丛丽","publisher":"北京大学出版社","pubtime":"20000702","inventory":3},
    {
        "bookid":"0027","bookname":"世界语言大观","author":"候丙辉","publisher":"经济科学出版社","pubtime":"20000814","inventory":2},
    {
        "bookid":"0029","bookname":"操作系统概论","author":"聂元名","publisher":"清华大学出版社","pubtime":"20001028","inventory":1},
    {
        "bookid":"0016","bookname":"数据库系统概念","author":"吴红","publisher":"机械工业出版社","pubtime":"20000328","inventory":3},
    {
        "bookid":"0005","bookname":"java基础","author":"王一","publisher":"电子工业出版社","pubtime":"19990528","inventory":3},
    {
        "bookid":"0032","bookname":"SOL使用手册","author":"贺民","publisher":"电子工业出版社","pubtime":"19990425","inventory":2}]

从文件Books.json可见整个文档结构是JSON数组，因为JSON字符串的开始和结尾被中括号括起来，这说明是JSON数组。JSON数组的每一个元素是JSON对象，因为JSON对象是用大括号括起来的

解析JSON文档代码如下：

private val bookList: List<Book>
            get() {
        
                // 数据文件
                val dbFile = "./db/Books.json"
                //  读取文件
                (FileReader(dbFile)).use {
         fileReader ->
                    val jsonString = fileReader.readText()
                    val gson = Gson()
                    val list = gson.fromJson<List<Book>>(jsonString)
                    return list
                }
            }

\[BookTableModel.kt\] 模型代码：

package com.dingjiaxiong
    
    import com.github.salomonbrys.kotson.fromJson
    import com.google.gson.Gson
    import java.io.FileReader
    import javax.swing.table.AbstractTableModel
    
    //图书实体类
    data class Book(
        // 图书编号
        val bookid: String,
        // 图书名称
        val bookname: String,
        // 图书作者
        val author: String,
        // 出版社
        val publisher: String,
        // 出版日期
        val pubtime: String,
        // 库存数量
        val inventory: Int
    )
    
    
    class BookTableModel() : AbstractTableModel() {
        
        private val bookList: List<Book>
            get() {
        
                // 数据文件
                val dbFile = "./db/Books.json"
                //  读取文件
                (FileReader(dbFile)).use {
         fileReader ->
                    val jsonString = fileReader.readText()
                    val gson = Gson()
                    val list = gson.fromJson<List<Book>>(jsonString)
                    return list
                }
            }
    
        // 列名数组
        private val columnNames = arrayOf("书籍编号", "书籍名称", "作者", "出版社", "出版日期", "库存数量")
    
        // 获得行数
        override fun getRowCount(): Int = bookList.size
    
        // 获得列数
        override fun getColumnCount(): Int = columnNames.size
    
        // 获得row行col列的数据
        override fun getValueAt(row: Int, col: Int): Any? {
        
            val (bookid, bookname, author, publisher, pubtime, inventory) = bookList[row]
            return when (col) {
        
                0 -> bookid
                1 -> bookname
                2 -> author
                3 -> publisher
                4 -> pubtime
                5 -> inventory
                else -> null
            }
        }
    
        // 获得某列的名字
        override fun getColumnName(col: Int): String = columnNames[col]
    }

上述代码是自定义的模型，它继承了抽象类AbstractTableModel。抽象类AbstractTableModel要求必须实现getColumnCount()、getRowCount()和getValueAt(row: Int, col: Int)三个抽象函数，getColumnCount()函数提供表格列数，getRowCount()函数提供表格的行数，getValueAt(row: Int, col: Int)函数提供了指定行和列时单元格内容。getColumnName(col: Int)函数不是抽象类要求实现的函数，重写该函数能够给表格提供有意义的列名。

窗口代码：

package com.dingjiaxiong
    
    import java.awt.BorderLayout
    import java.awt.Font
    import java.awt.Toolkit
    import javax.swing.JFrame
    import javax.swing.JScrollPane
    import javax.swing.JTable
    import javax.swing.ListSelectionModel
    import javax.swing.ListSelectionModel.SINGLE_SELECTION
    
    class MyFrameTable(
        title: String,
    ) : JFrame(title) {
        
    
        // 获得当前屏幕的宽高
        private val screenWidth = Toolkit.getDefaultToolkit().screenSize.getWidth()
        private val screenHeight = Toolkit.getDefaultToolkit().screenSize.getHeight()
    
        private val table: JTable
    
        init {
        
            val model = BookTableModel()
    
            table = JTable(model)
            with(table) {
        
                // 设置表中内容字体
                font = Font("微软雅黑", Font.PLAIN, 16)
                // 设置表列标题字体
                tableHeader.font = Font("微软雅黑", Font.BOLD, 16)
                // 设置表行高
                rowHeight = 40
                // 设置为单行选中模式
                setSelectionMode(SINGLE_SELECTION)
            }
            // 返回当前行的状态模型
            val rowSM = table.selectionModel
            // 注册侦听器，选中行发生更改时触发
            rowSM.addListSelectionListener {
         e ->
                //只处理鼠标按下
                if (!e.valueIsAdjusting) {
        
                    return@addListSelectionListener
                }
                val lsm = e.source as ListSelectionModel
                if (lsm.isSelectionEmpty) {
        
                    println("没有选中行")
                } else {
        
                    val selectedRow = lsm.minSelectionIndex
                    println("第" + selectedRow + "行被选中")
                }
            }
    
            val scrollPane = JScrollPane()
            scrollPane.setViewportView(table)
            contentPane.add(scrollPane, BorderLayout.CENTER)
    
            // 设置窗口大小
            setSize(960, 640)
            // 计算窗口位于屏幕中心的坐标
            val x = (screenWidth - 960).toInt() / 2
            val y = (screenHeight - 640).toInt() / 2
            // 设置窗口位于屏幕中心
            setLocation(x, y)
            // 设置窗口可见
            isVisible = true
        }
    
    }
    
    
    // 主函数
    fun main() {
        
        MyFrameTable("图书库存")
    }

运行效果

![在这里插入图片描述][37e593b7926b42b5b76607dfa4d49666.gif_pic_center]

[707492f2c4fd488086b54048c9357fd5.png_pic_center]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/23/18623123a0954cd984ccb52a0763cd61.png
[cab37fbb8c16486eaaf1e3667c2de6d9.png_pic_center]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/23/ad11e8ad39b449da9abd3fdb8a5131c5.png
[37e593b7926b42b5b76607dfa4d49666.gif_pic_center]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/23/e2d676f6776e452eb7a552b8967a5f2f.png