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By: Jeremy Smith. Android GUI. Table of Contents. Introduction Droid Draw Add XML file Layouts LinearLayout RelativeLayout Objects Notifications Toast Status Bar Dialog Menus Events Listeners Handlers Focus Source. Introduction.
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By: Jeremy Smith Android GUI
Table of Contents • Introduction • Droid Draw • Add XML file • Layouts • LinearLayout • RelativeLayout • Objects • Notifications • Toast • Status Bar • Dialog • Menus • Events • Listeners • Handlers • Focus • Source
Introduction • In Android, the UI is built using View and ViewGroup objects. • Views are a base for subclasses called “Widgets,” which offer fully implemented UI objects. (Ex. Text fields and buttons) • ViewGroups are a base for “layouts,” which offer different kinds of layout architectures. • Android GUI’s are coded in a version of XML and are based on the Views and ViewGroups.
Adding XML Files • Add an Android specific XML file to a project. • In your android project open up the res folder. • Then open the layout folder and you will see a generic file called main.xml • To add a XML file simply right click and add a new file. Under Android select the Android XML file and you have a brand new XML file open to edit in your project.
Layouts • Writing XML ( Android has its own XML vocabulary ) • Used for designing UI layouts and screen elements • Each layout must have only one root element. (parent) • After you create an initial layout you can add additional layouts and widgets to the layout. (child objects) • Position, Size, Padding and Margins Ex. getLeft(), getHight(), getPadding()
Common Layouts LinearLayout RelativeLayout
Widgets • The visual UI elements to be used on your Application screen. • Includes Buttons, Images, dialog and many other objects. • Interfaces & Classes
How To Create a Button • In the java source code • In the XML layout
Notifications • For a situation where you may need to notify a user about an event from your application • 3 Types • Toast Notification • Brief message that comes form the background • Status Bar Notification • Background reminders that request the user’s response • Dialog Notification • Activity-related notifications, sometimes require an user interaction. Toast Notification Status Bar Notification • Dialog Notification
Toast Notification • Initiating a Toast object • Initiate toast from the source code • Or by chaining methods
Status Bar Notifications • How to create a status bar notification: • Reference the NotificationManager: • Instantiate the Notification: • Define the Notification's expanded message and Intent: 4. Pass the Notification to the NotificationManager:
Dialog Notifications • Types of Dialogs • AlertDialog • Can have buttons, selectable items, and text dialog. • ProgressDialog • Displays a wheel or progress bar, also supports buttons. • DatePickerDialog • Allows user to select a date. • TimePickerDialog • Allows user to select a time. • CustomDialogs • Create your own dialog to suit your needs. • Examples
Creating Menus • Allows users to access application functions and settings. • 3 Types of menus • Options Menu • Appear when user presses the hard MENU button • Two Types • Icon Menu • Expanded Menu • Context Menu • Floating list of menu items, appears after a long-press on an item. • Submenu • Floating list of menu items that the user opens by pressing a menu item in the Options Menu or context menu. • Example Menus
Source • http://developer.android.com/guide/topics/ui/index.html