In most applications, it is a good idea to begin a drag and drop operation only after a mouse button has been pressed and the cursor has been moved a certain distance. To start a drag, create a QDrag object, and call its exec() function. These quantities provide sensible default values for you to use if you provide drag and drop support in your widgets. Use of high values for this quantity prevents accidental dragging when the user only meant to click on an object. QApplication::startDragDistance indicates how far the user has to move the mouse while holding down a mouse button before the movement will be interpreted as dragging.QApplication::startDragTime describes the amount of time in milliseconds that the user must hold down a mouse button over an object before a drag will begin.The QApplication object provides some properties that are related to drag and drop operations: These classes deal with drag and drop and the necessary mime type encoding and decoding.Įvent which is sent to a widget when a drag and drop action enters itĮvent that is sent to a widget when a drag and drop action leaves itĮvent which is sent while a drag and drop action is in progressĮvent which is sent when a drag and drop action is completedĬonverts between a MIME type and a Uniform Type Identifier (UTI) format More information is available in Using drag and drop with item views and Graphics View Framework. Drag and drop operations are also supported by Qt's item views and by the graphics view framework.
This document describes the basic drag and drop mechanism and outlines the approach used to enable it in custom widgets. (In the literature this is referred to as a "direct manipulation model".) Drag and drop is similar in function to the clipboard's cut and paste mechanism. Drag and drop provides a simple visual mechanism which users can use to transfer information between and within applications.
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