使用反射将可见的false设置为按钮，可以吗？

Question

I just trying hide button through relfection.

Class userClass = Class.forName("vistas.RegistroPersonal");
Field f = userClass.getDeclaredField("btneliminar");
f.setAccessible(true);
f.setVisible(false);

is there a way... field does not have setVisible method...

Answer 1

The setVisible() method on a Field does not exist, what you need to do is get a reference on the setVisible(boolean) Method (by its name & parameter types) and then invoke it:

public static void main(String[] args) throws Exception {
    TestApplication application = new TestApplication();
    Field field = TestApplication.class.getDeclaredField("button1");
    // This will allow us to access the button1 field even if it's private
    field.setAccessible(true);
    Method method = JButton.class.getMethod("setVisible", Boolean.TYPE);

    Object button = field.get(application);
    method.invoke(button, Boolean.FALSE);
}

public static class TestApplication {
    private JButton button1 = new JButton();
}

You need an instance of something to start with, if you start with the object owning your button then you can get its button via a Field and then invoke the Method. If you start with a button instance you can call the Method.

Please note that reflection seems like a convoluted way to do things here, the equivalent would be simply:

    TestApplication application = new TestApplication();
    application.button1.setVisible(false); 

Answer 2

To reflectivly call properties of a Java Bean such as Swing components, the recommended way is to use the Introspector class.

Some time ago, I've written a utility class, BeanIntrospector , to help working with beans and properties:

BeanIntrospector.setPropertyValue("visible", Boolean.FALSE, button, null);

The library is available from Maven Central:

<dependency>
  <groupId>org.softsmithy.lib</groupId>
  <artifactId>softsmithy-lib-beans</artifactId>
  <version>2.0</version>
</dependency>

The library is Open Source and the code is available on GitHub: https://github.com/SoftSmithy/softsmithy-lib