How do you implement drag and drop?
Most modern web browsers have implemented native drag-and-drop based on the HTML5 spec. By default, only image and text can be draggable. To drag an image, you simply hold the mouse button down and then move it. To drag the text, you need to highlight some text and drag it in the same way as you would drag an image.
How to implement drag and drop in Android?
A drag and drop operation starts when the user makes a UI gesture that your app recognizes as a signal to start dragging data. In response, the app notifies the system that a drag and drop operation is starting. The system calls back to your app to get a representation of the data being dragged (a drag shadow).