什么时候应该在java中使用JFrame.add（组件）和JFrame.getContentPane（）。add（component） [英] when should I use JFrame.add(component) and JFrame.getContentPane().add(component) in java

问题描述

他们之间是否存在差异，是否有任何条件应该使用一个而不是另一个？

Is there a difference between them and are there any conditions in which one should be used instead of the other?

推荐答案

根据我从Javadocs的理解，JFrame.add称之为后者。这是一种方便的方法来解决AWT框架和Swings JFrame之间的不兼容问题。

From what I understand from Javadocs, JFrame.add calls the latter. It is a convenience method to get around the incompatibility between AWT's frame and Swings JFrame.

来自 javadocs for JFrame ：

JFrame类与Frame略有不兼容。与所有其他
JFC / Swing顶级容器一样，JFrame包含一个JRootPane作为其
唯一子容器。根窗格提供的内容窗格应作为
规则包含JFrame显示的所有非菜单组件。
这与AWT Frame案例不同。作为一个方便的添加和
其变种，删除和setLayout已被覆盖，以根据需要转发到
的contentPane。这意味着你可以写：

The JFrame class is slightly incompatible with Frame. Like all other JFC/Swing top-level containers, a JFrame contains a JRootPane as its only child. The content pane provided by the root pane should, as a rule, contain all the non-menu components displayed by the JFrame. This is different from the AWT Frame case. As a conveniance add and its variants, remove and setLayout have been overridden to forward to the contentPane as necessary. This means you can write:

   `frame.add(child);`

孩子将被添加到
contentPane。内容窗格始终为非null。尝试将
设置为null将导致JFrame抛出异常。
默认内容窗格将在其上设置BorderLayout管理器。有关添加，删除和设置JFrame的
LayoutManager的详细信息，请参阅
到RootPaneContainer。

And the child will be added to the contentPane. The content pane will always be non-null. Attempting to set it to null will cause the JFrame to throw an exception. The default content pane will have a BorderLayout manager set on it. Refer to RootPaneContainer for details on adding, removing and setting the LayoutManager of a JFrame.

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