使用按钮将TextField的值从一个类获取到另一个类(Getting the value of TextField from one class to another with button)

我正在努力使用Vaadin从另一个类中获取文本字段的值。

我的解决方案是这样的。

public class MyTextField{ String str; public MyTextField(){ TextField text = new TextField(); str = text.getValue().toString(); } public String getStr(){ return str; } } public class MyButton{ public MyButton(){ Button button = new Button("UPDATE"); button.addListener(new Button.ClickListener(){ @Override public void buttonClick(ClickEvent event) { MyTextField text = new MyTextField(); System.out.println(text.getStr()); } }); } }

问题是，我总是得到null结果。任何帮助都非常感谢。谢谢。

I'm working on getting the value of a textfield from another class using Vaadin.

my solution is something like this.

public class MyTextField{ String str; public MyTextField(){ TextField text = new TextField(); str = text.getValue().toString(); } public String getStr(){ return str; } } public class MyButton{ public MyButton(){ Button button = new Button("UPDATE"); button.addListener(new Button.ClickListener(){ @Override public void buttonClick(ClickEvent event) { MyTextField text = new MyTextField(); System.out.println(text.getStr()); } }); } }

the problem is, I always get null result. any help is highly appreciated. Thank you.

最满意答案

我宁愿做这样的事情来实现你正在做的事情。这是基于您尝试在单击按钮时读取用户输入值的假设。有两种方法可以实现这一目标。

选项1

public class MyTextField extends TextField{ public MyTextField(){ } public String getStr(){ return this.getValue(); } } public class MyButton extends Button{ public MyButton(){ setCaption("UPDATE"); } } //Add in your presentation logic final MyTextField text = new MyTextField(); MyButton button = new MyButton(); mainLayout.addComponent(text); mainLayout.addComponent(button); button.addClickListener(new ClickListener() { @Override public void buttonClick(ClickEvent event) { System.out.println(text.getStr()); } });

选项2

public class MyTextField extends TextField{ public MyTextField(){ } public String getStr(){ return this.getValue(); } } public class MyButton extends Button{ public MyButton(final MyTextField text){ setCaption("UPDATE"); addClickListener(new ClickListener() { @Override public void buttonClick(ClickEvent event) { System.out.println(text.getStr()); } }); } } //And in your presentation logic final MyTextField text = new MyTextField(); MyButton button = new MyButton(text); mainLayout.addComponent(text); mainLayout.addComponent(button);

如果这不是您所期望的，请告诉我。

还有Kudos给气垫船充满鳗鱼试图帮助他

谢谢。

I would rather do some thing like this, to achieve what you are doing. This is based on the assumption that you are trying to read the user entered value on click of a button. There are two option to achieve this.

Option 1

public class MyTextField extends TextField{ public MyTextField(){ } public String getStr(){ return this.getValue(); } } public class MyButton extends Button{ public MyButton(){ setCaption("UPDATE"); } } //Add in your presentation logic final MyTextField text = new MyTextField(); MyButton button = new MyButton(); mainLayout.addComponent(text); mainLayout.addComponent(button); button.addClickListener(new ClickListener() { @Override public void buttonClick(ClickEvent event) { System.out.println(text.getStr()); } });

Option 2

public class MyTextField extends TextField{ public MyTextField(){ } public String getStr(){ return this.getValue(); } } public class MyButton extends Button{ public MyButton(final MyTextField text){ setCaption("UPDATE"); addClickListener(new ClickListener() { @Override public void buttonClick(ClickEvent event) { System.out.println(text.getStr()); } }); } } //And in your presentation logic final MyTextField text = new MyTextField(); MyButton button = new MyButton(text); mainLayout.addComponent(text); mainLayout.addComponent(button);

Please let me know if in case if this is not what you are expecting.

And Kudos to Hovercraft Full Of Eels for trying to help him out

Thanks.

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