🚣🏼 🙎🏾 🖇️ JavaFX上带有按钮的窗口： 👐 🆒 👨‍❤️‍👨

你好

直到最近，我对创建任何图形界面的知识还是零。因此，决定稍微摆动一下Internet并创建一个带有一些按钮的窗口，单击该按钮会发生一些事情。也许在本文中有人会找到曾经出现的问题的答案。同时，我希望提出严肃认真的批评。

会发生什么？

由于我的目标是处理JavaFX，因此我需要在窗口中提供某种功能。这个想法是这样的：创建一组人（假设他们在公司工作），我们将为每个人知道姓名，年龄，薪水和婚姻状况。我们的窗口首先显示每个人的信息，其次，更改员工的薪水，其次，可以添加新员工，最后，可以根据需要过滤员工从其属性的值。结果应该是这样的：

开始使用

首先，我们创建公司的主类，从该类将启动应用程序：

package company; public class Company { public static void main(String[] args) { } }

在这个类中，我们将扩展 Application类的功能。从它开始，我们主要需要一个start（）方法，在该方法中将执行主要操作（我们将跳过此方法中发生的错误；换句话说，如果出现问题，我们的窗口将不会关闭，但是StackTrace错误将出现在控制台中）：

 package company; import javafx.application.Application; import javafx.stage.Stage; public class Company extends Application { public void start(Stage primaryStage) throws Exception { } public static void main(String[] args) { launch(args); } }

太好了为了与公司员工的代表一起工作，请创建User类：此类的对象，并将充当员工。

用户类别

 package company; public class User { User(String name, int age, int salary, boolean married) { this.name = name; this.age = age; this.salary = salary; this.married = married; } public void changeSalary(int x) { salary = (salary + x <= 0)? 0: salary + x; } public String toString() { return name; } public String getAge() { return String.valueOf(age); } public String getSalary() { return String.valueOf(salary); } public String getMarried() { return (married)? ("married"):("single"); } String name; int age; int salary; boolean married; }

建立

到目前为止，当应用程序启动时，对我们来说什么都没有发生。要至少显示一个窗口，必须添加它。我们会做到的。

 package company; import javafx.application.Application; import javafx.scene.Group; import javafx.scene.Scene; import javafx.stage.Stage; public class Company extends Application { public void start(Stage primaryStage) throws Exception { Scene scene = new Scene(root, WIDTH, HEIGHT); primaryStage.setTitle("Company"); primaryStage.setScene(scene); primaryStage.show(); } public static void main(String[] args) { launch(args); } Group root = new Group(); final private int WIDTH = 1000; final private int HEIGHT = 600; }

我们刚刚做了什么：我们添加了一个大小场景

宽 度 \乘 以 高 度

$宽度\乘以高度$ ，给她起了“公司”的名字。我们场景中有一个根组，它实际上是一个包含所有按钮的“容器”。

与我们的员工一起添加一个下拉列表。让我们创建一个HBox，在其中放置组合框userBox下拉列表和一个将显示有关员工信息的按钮（将HBox放置在VBox中）：

 package company; import java.util.ArrayList; import javafx.application.Application; import javafx.geometry.Insets; import javafx.scene.Group; import javafx.scene.Scene; import javafx.scene.control.ComboBox; import javafx.scene.layout.HBox; import javafx.scene.layout.VBox; import javafx.scene.text.Text; import javafx.stage.Stage; public class Company extends Application { public void start(Stage primaryStage) throws Exception { users.add(new User("Alice", 20, 150, false)); users.add(new User("Bob", 34, 300, true)); users.add(new User("Peter", 18, 100, false)); users.add(new User("Kate", 38, 300, true)); users.add(new User("Steve", 31, 250, true)); users.add(new User("Alan", 62, 500, true)); users.add(new User("Julia", 33, 320, true)); users.add(new User("Patric", 37, 300, true)); users.add(new User("Alexander", 34, 280, true)); users.add(new User("George", 28, 180, true)); users.add(new User("Mary", 22, 190, false)); userBox.getItems().addAll(users); root.getChildren().add(strings); strings.setPadding(new Insets(10, 30, 10, 30)); strings.setSpacing(20); strings.getChildren().add(new Text("Select the user")); strings.getChildren().add(buttonBox); buttonBox.setSpacing(10); buttonBox.getChildren().add(userBox); Scene scene = new Scene(root, WIDTH, HEIGHT); primaryStage.setTitle("Company"); primaryStage.setScene(scene); primaryStage.show(); } public static void main(String[] args) { launch(args); } Group root = new Group(); VBox strings = new VBox(); HBox buttonBox = new HBox(); ComboBox<User> userBox = new ComboBox<>(); final private int WIDTH = 1000; final private int HEIGHT = 600; private ArrayList<User> users = new ArrayList<>(); }

什么是VBox，HBox和ComboBox

HBox是一组按钮，文本，输入字段，其每个对象均按水平顺序排列。与此类似，VBox相同，但是垂直存储其对象（子代）。我们将使用以下方案：创建一个VBox，在其中放置几个HBox'ov，在每个HBox'ov中放置一个按钮和字段序列。

ComboBox本身就是一个下拉列表。

现在，我们要创建一个按钮，该按钮将显示有关所选雇员的信息。添加按钮本身（Button）和文本字段（TextField），将在其中显示文本。我们将以下两个对象添加到HBox中：

 package company; /* */ public class Company extends Application { public void start(Stage primaryStage) throws Exception { /* */ buttonBox.setSpacing(10); buttonBox.getChildren().add(userBox); buttonBox.getChildren().add(buttonGetInfo); buttonBox.getChildren().add(textInfo); /* */ } /* */ Button buttonGetInfo = new Button("Info"); Text textInfo = new Text(); /* */ }

但是到目前为止，此按钮没有任何作用。为了让她做某事，必须为她分配一个操作：

 buttonGetInfo.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent e) { User u = (User) userBox.getSelectionModel().getSelectedItem(); if (u != null) { textInfo.setText("Age is " + u.getAge() + ", " + "Salary is " + u.getSalary() + ", " + "Relationship: " + u.getMarried()); } else { textInfo.setText("User not selected"); } } });

进一步行动

以完全相同的方式，我们添加了两个HBox：第二个是工资变动，第三个是增加新员工。由于此处的逻辑完全相同，因此我们跳过了对这些要点的解释，并立即显示结果：

代号

 package company; import java.util.ArrayList; import javafx.application.Application; import javafx.event.ActionEvent; import javafx.event.EventHandler; import javafx.geometry.Insets; import javafx.scene.Group; import javafx.scene.Scene; import javafx.scene.control.Button; import javafx.scene.control.ComboBox; import javafx.scene.control.TextField; import javafx.scene.layout.HBox; import javafx.scene.layout.VBox; import javafx.scene.text.Text; import javafx.stage.Stage; public class Company extends Application { public void start(Stage primaryStage) throws Exception { users.add(new User("Alice", 20, 150, false)); users.add(new User("Bob", 34, 300, true)); users.add(new User("Peter", 18, 100, false)); users.add(new User("Kate", 38, 300, true)); users.add(new User("Steve", 31, 250, true)); users.add(new User("Alan", 62, 500, true)); users.add(new User("Julia", 33, 320, true)); users.add(new User("Patric", 37, 300, true)); users.add(new User("Alexander", 34, 280, true)); users.add(new User("George", 28, 180, true)); users.add(new User("Mary", 22, 190, false)); userBox.getItems().addAll(users); root.getChildren().add(strings); strings.setPadding(new Insets(10, 30, 10, 30)); strings.setSpacing(20); strings.getChildren().add(new Text("Select the user")); strings.getChildren().add(buttonBox); strings.getChildren().add(new Text("Change the salary")); strings.getChildren().add(changeSalaryBox); strings.getChildren().add(new Text("Add new User")); strings.getChildren().add(addUserBox); buttonBox.setSpacing(10); buttonBox.getChildren().add(userBox); buttonBox.getChildren().add(buttonGetInfo); buttonBox.getChildren().add(textInfo); changeSalaryBox.setSpacing(10); changeSalaryBox.getChildren().add(buttonChangeSalary); changeSalaryBox.getChildren().add(howMuchChange); addUserBox.setSpacing(10); addUserBox.getChildren().add(new Text("Name: ")); addUserBox.getChildren().add(name); addUserBox.getChildren().add(new Text("Age: ")); addUserBox.getChildren().add(age); addUserBox.getChildren().add(new Text("Salary: ")); addUserBox.getChildren().add(salary); addUserBox.getChildren().add(new Text("Married: ")); addUserBox.getChildren().add(married); addUserBox.getChildren().add(buttonAddUser); buttonGetInfo.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent e) { User u = (User) userBox.getSelectionModel().getSelectedItem(); if (u != null) { textInfo.setText("Age is " + u.getAge() + ", " + "Salary is " + u.getSalary() + ", " + "Relationship: " + u.getMarried()); } else { textInfo.setText("User not selected"); } } }); buttonChangeSalary.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent e) { User u = (User) userBox.getSelectionModel().getSelectedItem(); if(u != null) { u.changeSalary(Integer.parseInt(howMuchChange.getText())); textInfo.setText("Age is " + u.getAge() + ", " + "Salary is " + u.getSalary() + ", " + "Relationshp: " + u.getMarried()); howMuchChange.clear(); } } }); buttonAddUser.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent e) { String m = married.getText(); boolean mm = (m.equals("married"))? true:false; User u = new User(name.getText(), Integer.parseInt(age.getText()), Integer.parseInt(salary.getText()), mm); users.add(u); userBox.getItems().addAll(u); name.clear(); age.clear(); salary.clear(); married.clear(); } }); Scene scene = new Scene(root, WIDTH, HEIGHT); primaryStage.setTitle("Company"); primaryStage.setScene(scene); primaryStage.show(); } public static void main(String[] args) { launch(args); } Group root = new Group(); VBox strings = new VBox(); HBox buttonBox = new HBox(); ComboBox<User> userBox = new ComboBox<>(); Button buttonGetInfo = new Button("Info"); Text textInfo = new Text(); HBox changeSalaryBox = new HBox(); Button buttonChangeSalary = new Button("Change salary"); TextField howMuchChange = new TextField(); HBox addUserBox = new HBox(); Button buttonAddUser = new Button("Add User"); TextField name = new TextField(); TextField age = new TextField(); TextField salary = new TextField(); TextField married = new TextField(); final private int WIDTH = 1000; final private int HEIGHT = 600; private ArrayList<User> users = new ArrayList<>(); }

筛选器

现在，按特征添加对员工的“筛选”。同样，我们将使用相同的逻辑使用ComboBox添加过滤器列表。

 package company; /* */ public class Company extends Application { public void start(Stage primaryStage) throws Exception { /* */ ageFilterBox.getItems().addAll( "no matter", "over 20", "over 30", "over 40" ); salaryFilterBox.getItems().addAll( "no matter", "over 150", "over 250", "over 500" ); relationshipFilterBox.getItems().addAll( "no matter", "married", "single" ); /* */ strings.getChildren().add(filters); strings.getChildren().add(resultFilter); /* */ filters.setSpacing(10); filters.getChildren().add(new Text("Age")); filters.getChildren().add(ageFilterBox); filters.getChildren().add(new Text("Salary")); filters.getChildren().add(salaryFilterBox); filters.getChildren().add(new Text("Relationship")); filters.getChildren().add(relationshipFilterBox); filters.getChildren().add(filter); /* */ filter.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent e) { int age; int index = ageFilterBox.getSelectionModel().getSelectedIndex(); age = (index == 0)? 0: (index == 1)? 21: (index == 2)? 31: 41; int salary; index = salaryFilterBox.getSelectionModel().getSelectedIndex(); salary = (index == 0)? 0 : (index == 1)? 151 : (index == 2)? 251:501; boolean relate; index = relationshipFilterBox.getSelectionModel().getSelectedIndex(); relate = (index == 1)? true: (index == 2)? false: true; List<User> list; if(index != 0) { list = users.stream(). filter(u -> u.age > age). filter(u -> u.salary > salary). filter(u -> u.married == relate). collect(Collectors.toList()); } else { list = users.stream(). filter(u -> u.age > age). filter(u -> u.salary > salary). collect(Collectors.toList()); } String res = ""; for(User u: list) { res += u.toString() + ", "; } resultFilter.setText(res); } }); /* */ } /* */ HBox filters = new HBox(); ComboBox<String> ageFilterBox = new ComboBox<>(); ComboBox<String> salaryFilterBox = new ComboBox<>(); ComboBox<String> relationshipFilterBox = new ComboBox<>(); Button filter = new Button("filter"); Text resultFilter = new Text(); /* */ }

做完了！

完整代码

公司类（主营）

 package company; import java.util.ArrayList; import java.util.List; import java.util.stream.Collectors; import javafx.application.Application; import javafx.event.ActionEvent; import javafx.event.EventHandler; import javafx.geometry.Insets; import javafx.scene.Group; import javafx.scene.Scene; import javafx.scene.control.Button; import javafx.scene.control.ComboBox; import javafx.scene.control.TextField; import javafx.scene.layout.HBox; import javafx.scene.layout.VBox; import javafx.scene.text.Text; import javafx.stage.Stage; public class Company extends Application { @Override public void start(Stage primaryStage) throws Exception { users.add(new User("Alice", 20, 150, false)); users.add(new User("Bob", 34, 300, true)); users.add(new User("Peter", 18, 100, false)); users.add(new User("Kate", 38, 300, true)); users.add(new User("Steve", 31, 250, true)); users.add(new User("Alan", 62, 500, true)); users.add(new User("Julia", 33, 320, true)); users.add(new User("Patric", 37, 300, true)); users.add(new User("Alexander", 34, 280, true)); users.add(new User("George", 28, 180, true)); users.add(new User("Mary", 22, 190, false)); userBox.getItems().addAll(users); ageFilterBox.getItems().addAll( "no matter", "over 20", "over 30", "over 40" ); salaryFilterBox.getItems().addAll( "no matter", "over 150", "over 250", "over 500" ); relationshipFilterBox.getItems().addAll( "no matter", "married", "single" ); root.getChildren().add(strings); strings.setPadding(new Insets(10, 30, 10, 30)); strings.setSpacing(20); strings.getChildren().add(new Text("Select the user")); strings.getChildren().add(buttonBox); strings.getChildren().add(new Text("Change the salary")); strings.getChildren().add(changeSalaryBox); strings.getChildren().add(new Text("Add new User")); strings.getChildren().add(addUserBox); strings.getChildren().add(filters); strings.getChildren().add(resultFilter); buttonBox.setSpacing(10); buttonBox.getChildren().add(userBox); buttonBox.getChildren().add(buttonGetInfo); buttonBox.getChildren().add(textInfo); changeSalaryBox.setSpacing(10); changeSalaryBox.getChildren().add(buttonChangeSalary); changeSalaryBox.getChildren().add(howMuchChange); addUserBox.setSpacing(10); addUserBox.getChildren().add(new Text("Name: ")); addUserBox.getChildren().add(name); addUserBox.getChildren().add(new Text("Age: ")); addUserBox.getChildren().add(age); addUserBox.getChildren().add(new Text("Salary: ")); addUserBox.getChildren().add(salary); addUserBox.getChildren().add(new Text("Married: ")); addUserBox.getChildren().add(married); addUserBox.getChildren().add(buttonAddUser); filters.setSpacing(10); filters.getChildren().add(new Text("Age")); filters.getChildren().add(ageFilterBox); filters.getChildren().add(new Text("Salary")); filters.getChildren().add(salaryFilterBox); filters.getChildren().add(new Text("Relationship")); filters.getChildren().add(relationshipFilterBox); filters.getChildren().add(filter); Scene scene = new Scene(root, WIDTH, HEIGHT); primaryStage.setTitle("Company"); primaryStage.setScene(scene); primaryStage.show(); buttonGetInfo.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent e) { User u = (User) userBox.getSelectionModel().getSelectedItem(); if (u != null) { textInfo.setText("Age is " + u.getAge() + ", " + "Salary is " + u.getSalary() + ", " + "Relationship: " + u.getMarried()); } else { textInfo.setText("User not selected"); } } }); buttonChangeSalary.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent e) { User u = (User) userBox.getSelectionModel().getSelectedItem(); if(u != null) { u.changeSalary(Integer.parseInt(howMuchChange.getText())); textInfo.setText("Age is " + u.getAge() + ", " + "Salary is " + u.getSalary() + ", " + "Relationshp: " + u.getMarried()); howMuchChange.clear(); } } }); buttonAddUser.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent e) { String m = married.getText(); boolean mm = (m.equals("married"))? true:false; User u = new User(name.getText(), Integer.parseInt(age.getText()), Integer.parseInt(salary.getText()), mm); users.add(u); userBox.getItems().addAll(u); name.clear(); age.clear(); salary.clear(); married.clear(); } }); filter.setOnAction(new EventHandler<ActionEvent>() { @Override public void handle(ActionEvent e) { int age; int index = ageFilterBox.getSelectionModel().getSelectedIndex(); age = (index == 0)? 0: (index == 1)? 21: (index == 2)? 31: 41; int salary; index = salaryFilterBox.getSelectionModel().getSelectedIndex(); salary = (index == 0)? 0 : (index == 1)? 151 : (index == 2)? 251:501; boolean relate; index = relationshipFilterBox.getSelectionModel().getSelectedIndex(); relate = (index == 1)? true: (index == 2)? false: true; //resultFilter.setText(String.valueOf(age) + " " + String.valueOf(salary) + " "+ relate); List<User> list; if(index != 0) { list = users.stream(). filter(u -> u.age > age). filter(u -> u.salary > salary). filter(u -> u.married == relate). collect(Collectors.toList()); } else { list = users.stream(). filter(u -> u.age > age). filter(u -> u.salary > salary). collect(Collectors.toList()); } String res = ""; for(User u: list) { res += u.toString() + ", "; } resultFilter.setText(res); } }); } public static void main(String[] args) { launch(args); } Group root = new Group(); VBox strings = new VBox(); HBox buttonBox = new HBox(); HBox changeSalaryBox = new HBox(); HBox addUserBox = new HBox(); HBox filters = new HBox(); ComboBox<User> userBox = new ComboBox<>(); ComboBox<String> ageFilterBox = new ComboBox<>(); ComboBox<String> salaryFilterBox = new ComboBox<>(); ComboBox<String> relationshipFilterBox = new ComboBox<>(); final private int WIDTH = 1000; final private int HEIGHT = 600; private ArrayList<User> users = new ArrayList<>(); Button buttonGetInfo = new Button("Info"); Text textInfo = new Text(); Button buttonChangeSalary = new Button("Change salary"); TextField howMuchChange = new TextField(); Button buttonAddUser = new Button("Add User"); TextField name = new TextField(); TextField age = new TextField(); TextField salary = new TextField(); TextField married = new TextField(); Button filter = new Button("filter"); Text resultFilter = new Text(); }

用户类别

 package company; public class User { User(String name, int age, int salary, boolean married) { this.name = name; this.age = age; this.salary = salary; this.married = married; } public void changeSalary(int x) { salary = (salary + x <= 0)? 0: salary + x; } public String toString() { return name; } public String getAge() { return String.valueOf(age); } public String getSalary() { return String.valueOf(salary); } public String getMarried() { return (married)? ("married"):("single"); } String name; int age; int salary; boolean married; }

那是什么

该程序本身没有任何意义，仅是为了熟悉JavaFX及其工具而编写的。例如，在某些地方，当更改薪水时，如果未选择用户或输入行，则不会考虑选项：在这些情况下，将出现错误。这同样适用于添加新员工时在其中输入信息的字段。最后，如果未在任何下拉列表中选择某个值，就会发生错误。如果需要，每个人都可以添加自己的这些弯路。

顺便说一下，在编写过滤器时，我使用了臭名昭著的StreamAPI和

l a m b d a

$\ lambda$ -缩短代码的表达式使代码易于理解并更具魅力。

资料来源：

JavaFX 8-Oracle帮助中心
关于JavaFX的创建和历史修改的一些知识
关于StreamAPI的精彩文章 vedenin1980和 $\ lambda$ -表达式

JavaFX上带有按钮的窗口：

会发生什么？

开始使用

建立

进一步行动

筛选器

那是什么

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