Java 如何使用元素的中心在 BoxLayout 中居中元素？
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How to center elements in the BoxLayout using center of the element?
提问by Roman
I use outputPanel.setLayout(new BoxLayout(outputPanel, BoxLayout.Y_AXIS));and then I add elements (for example JLabels, JButtons) to the outputPanel. For example: outputPanel.add(submitButton);.
我使用outputPanel.setLayout(new BoxLayout(outputPanel, BoxLayout.Y_AXIS));然后将元素（例如 JLabels、JButtons）添加到outputPanel. 例如：outputPanel.add(submitButton);。
I see that all added elements are "centered". It is good, because I do want my elements to be in the center. When I write "center" I mean "equal distance from left and right". But the problem is that the left part of the element is put into the center. And I want to have center of elements to be put into the center. How can I get this behavior?
我看到所有添加的元素都“居中”。这很好，因为我确实希望我的元素位于中心。当我写“中心”时，我的意思是“左右距离相等”。但问题是元素的左侧部分被放入了中心。我希望将元素的中心放入中心。我怎样才能得到这种行为？
采纳答案by Roman
The problem can be solved by using myLabel.setAlignmentX(Component.CENTER_ALIGNMENT);. It works with JLabel, JButtonand JRadioButton.
问题可以通过使用来解决myLabel.setAlignmentX(Component.CENTER_ALIGNMENT);。它适用于JLabel,JButton和JRadioButton。
回答by AdamK
So far the best method I've encountered that works with everytype of component:
1. Create a new JPanel:
到目前为止，我遇到的适用于所有类型组件的最佳方法：
1. 创建一个新的JPanel：
JPanel helperPanel = new JPanel();
2. Add the component (in this example submitButton) you wish to center horizontally to the JPanel :
helperPanel.add(submitButton);
3. Add the panel to your original panel (the one with the BoxLayout):
outerPanel.add(helperPanel);
That's it!
You could also set a maximum size on the helperPanelif you don't want the BoxLayout of the outerPanelto expand it.
If you're wondering why this works: the implicit layout manager of a JPanel is FlowLayout, which centers your elements automatically.
JPanel helperPanel = new JPanel();
2. 将submitButton您希望水平居中的组件（在本例中）helperPanel.add(submitButton);
添加到 JPanel ：
3. 将面板添加到原始面板（带有 BoxLayout 的面板）：
outerPanel.add(helperPanel);
就是这样！如果您不希望 的 BoxLayout展开它，您还可以在 上设置最大大小。
如果您想知道为什么会这样：JPanel 的隐式布局管理器是 FlowLayout，它会自动将您的元素居中。helperPanelouterPanel
