英文:
Navigation in vaadin with parameters
问题
在我的项目中，我有一个JPA数据库连接，用于存储练习。我从数据库中读取所有的练习，并将它们存储在变量allExercises中。然后，我将每个练习的标题保存在一个按钮中，将它们添加到GUI的一个框中，并添加一个点击监听器事件来处理导航到下一个视图。这个下一个视图是所选练习的详细视图。为了知道我点击了哪个练习，我想将练习对象的id作为参数传递。目前我有以下代码：
for(Exercise exercise : allExercises) {
// 创建带有练习标题的新按钮
Button bt = new Button(exercise.getTitle());
// 将按钮添加到框中
boxExerciseTitle.add(bt);
// 添加动作事件
bt.addClickListener(e -> UI.getCurrent().navigate(ExerciseDetailView.class, exercise.getId()));
}
这段代码不起作用。问题在于ID，或者说导航函数不能处理这两个参数。
我的目标是在详细视图中以以下方式读取参数：
public class ExerciseDetailView extends VerticalLayout implements View{
@Override
public void enter(ViewChangeEvent event) {
String myPassedId = event.getParameters();
...
}
}
如何更改我的代码，以便我可以在Vaadin中将ID作为参数传递？
英文:
In my project I have a jpa database connection where I store exercises. I read all exercises from the database and store them into the variable allExercises. Afterwards I save the title of each exercise in a button, add them to a box for the GUI and also add a click listener event that handles the navigation to the next view. This next view is a detail view of the chosen exercise. To know on which exercise I have clicked I want to pass the id of the exercise object as a parameter. For now I have following code:
for(Exercise exercise : allExercises) {
// create new button with exercise title
Button bt = new Button(exercise.getTitle());
// add button to box
boxExerciseTitle.add(bt);
// add action event
bt.addClickListener(e -> UI.getCurrent().navigate(ExerciseDetailView.class, exercise.getId()));
}
This code is not working. There is a problem with the ID respectively that the navigate function does not handle this two arguments.
My goal is to read the parameter in the detail view like that:
public class ExerciseDetailView extends VerticalLayout implements View{
@Override
public void enter(ViewChangeEvent event) {
String myPassedId = event.getParameters();
...
}
}
How can I change my code that I can pass the id as a parameter in Vaadin?
答案1
得分: 1
详细视图必须实现 HasUrlParameter，然后在 setParameter 方法中获取参数：
@Route(value = "exercise")
public class ExerciseDetailView extends VerticalLayout
implements HasUrlParameter<Long> {
@Override
public void setParameter(BeforeEvent event,
Long exerciseId) {
// 使用给定的ID查找单个练习
// Exercise exercise = exerciseRepository.findById(exerciseId);
}
}
文档链接：https://vaadin.com/docs/v14/flow/routing/tutorial-router-url-parameters.html
如果 exercise.getId() 的类型不是 Long，而是 Integer 或其他数字类型，请相应地更改 HasUrlParameter 的类型。
英文:
The detail view must implement HasUrlParameter and then you get the parameter in the setParameter method:
@Route(value = "exercise")
public class ExerciseDetailView extends VerticalLayout
implements HasUrlParameter<Long> {
@Override
public void setParameter(BeforeEvent event,
Long exerciseId) {
// find the single exercise using the given id
// Exercise exercise = exerciseRepository.findById(exerciseId);
}
}
Documentation: https://vaadin.com/docs/v14/flow/routing/tutorial-router-url-parameters.html
If the type of exercise.getId() is not Long but instead Integer or another Number, then change the type of HasUrlParameter accordingly.
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