Tham khảo tài liệu 'lwuit for java me developers- p7', công nghệ thông tin, kỹ thuật lập trình phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Chapter 11 You can modify the MIDlet such that the transition occurs between a form and a dialog. The resulting transition would look like this Summary This chapter has shown us quite a few things. We have seen how to animate objects by implementing the Animation interface. We have also seen how to use the transitions that come with the LWUIT library for forms dialogs and menus as well as for widgets like labels. We have also authored our own transition. The intricacies of designing transitions that work with dialogs have been dealt with in some detail. There are some more issues that may need to be addressed while building custom transitions. The source code of LWUIT transitions provides extensive insight into these factors especially from the perspective of handling graphics related issues and is an invaluable resource for a developer. 287 12 Painters All LWUIT components have a multi-layered structure. The first layer erases a visually obsolete widget and the subsequent layers then paint the background followed by the constituent parts of the new version. As a matter of fact the background too can be made up of several layers and that is not all. After a form has been fully rendered we can place a layer above it that can be drawn upon regardless of any changes or animations that may be taking place in the form below. Such a layer known as a GlassPane is usually transparent or translucent so that the form under it remains visible. The classes that work as a background painter or a glass pane must implement the Painter interface. In case more than one background painter is used they can be formed into a chain through the PainterChain class so that the background can be rendered layer-by-layer. Similarly a glass pane also can have many layers. In this chapter we shall familiarize ourselves with the Painter interface and the PainterChain class. We shall also learn with the help of examples how background painters and glass panes can be used. The Painter interface .
