The Java Tutorials have been written for JDK 8.Java教程是为JDK 8编写的。Examples and practices described in this page don't take advantage of improvements introduced in later releases and might use technology no longer available.本页中描述的示例和实践没有利用后续版本中引入的改进,并且可能使用不再可用的技术。See Java Language Changes for a summary of updated language features in Java SE 9 and subsequent releases.有关Java SE 9及其后续版本中更新的语言特性的摘要,请参阅Java语言更改。
See JDK Release Notes for information about new features, enhancements, and removed or deprecated options for all JDK releases.有关所有JDK版本的新功能、增强功能以及已删除或不推荐的选项的信息,请参阅JDK发行说明。
Generally during a drag operation, a component gives visual feedback when it can accept the data. It might highlight the drop location, or it might show a caret or a horizontal line where the insertion would occur. Swing renders the drop location when the canImport
method for the component's TransferHandler
returns true.
To control this programmatically, you can use the setShowDropLocation
method. Calling this method with true
causes the visual feedback for the drop location to always be displayed, even if the drop will not be accepted. Calling this method with false
prevents any visual feedback, even if the drop will be accepted. You always invoke this method from canImport
.
The Demo - LocationSensitiveDemo page includes a combo box that enables you to choose to always show the drop location, or never show the drop location, or the default behavior. But first we will talk about location sensitive drop.