如何使JCombobox看起来像JTextField [英] How to make JCombobox look like a JTextField

问题描述

是否有一种好的（简单的）方法可以使JCombobox看起来像JTextField？
我的意思是不应该有一个下拉按钮，但是当用户输入内容时它应该显示多种结果。

Is there a good(and easy) way to make a JCombobox look like a JTextField? By this I mean there should not be a dropdown button, but when the user enters something it should show multible results.

基本上与google，youtube相同，facebook等工作。

Basically the same way google, youtube, facebook etc. works.

推荐答案

JComboBox comboBox = new JComboBox();
comboBox.setUI(new BasicComboBoxUI() {
    @Override
    protected JButton createArrowButton() {
        return new JButton() {
            @Override
            public int getWidth() {
                return 0;
            }
        };
    }
});

使getWidth（）返回0确保：

a）按钮不是显示

b）没有为它保留空间，让你输入整个字段

Making getWidth() return 0 ensures that:
a) the button is not shown
b) no space is reserved for it, letting you type in the whole field

我发现我必须调用 .setUI（）通过 SwingUtilities.invokeLater（），但根据代码的结构，你可能不需要。

I found that I had to do invoke .setUI() via SwingUtilities.invokeLater(), but depending on the structure of your code, you might not have to.

如果你想要自动完成，可以在组合框中添加一些项目，并使用 AutoCompleteDecorator.decorate（comboBox） 。 AutoCompleteDecorator 类是 SwingX 的一部分，之前提到的。

If you want autocomplete, add some items to the combo box, and use AutoCompleteDecorator.decorate(comboBox). The AutoCompleteDecorator class is part of SwingX, as previously mentioned.

这可能会让你的盒子在使用另一个L&F时看起来很奇怪，所以你必须选择要实例化的CombiBoxUI，以获得正确的外观。

This might make your box look weird when using another L&F, so you will have to choose which CombiBoxUI to instantiate, to get the right look.

如果您不希望在组合框中没有任何内容时显示下拉菜单，请在BasicComboBoxUI中覆盖此方法：

If you do not want the drop-down to appear when there is nothing in the combo box, override this method in the BasicComboBoxUI as well:

@Override
public void setPopupVisible(JComboBox c, boolean v) {
    // keeps the popup from coming down if there's nothing in the combo box
    if (c.getItemCount() > 0) {
        super.setPopupVisible(c, v);
    }
}

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