BlackBerry : Develop Simple Apps
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BlackBerry Activities
- Start and run the Eclipse for BlackBerry as installed in the previous lecture.
- Open the Subversion Perspective in Eclipse for BlackBerry.
- Check out the Simple Sample from BlackBerry Course Repository
- Run the sample and change it.
- Define the main steps involved in developing BlackBerry applications.
- Write a small tutorial (main steps) about using Eclipse to develop BlackBerry applications.
Start the lab activities in the order defined below:
Read Code from the BlackBerry Samples
Here are some of the most important BlackBerry Samples The content from BlackBerry developer site has been used for these notes for which a grateful acknowledgment is made.
Active Text Fields
The active text field sample application shows how a BlackBerry® device user can access customized items from the context menu when a pattern is recognized in an active text field. You can create active text fields by using theActiveAutoTextEditField class and ActiveRichTextField class.
When the BlackBerry device starts, the application, pattern, and associated menu items are registered with thePatternRepository. When text with the matching pattern is found in an active text field, the text is highlighted. When the user clicks highlighted text, the context menu is displayed with the menu items that are associated with the pattern.
In the sample application, when the user types a nine-digit number into an active text field, the user can click this number and a context menu with Status and Location options appears. When the user clicks one of the options, the application displays the requested information.
Bitmap Scaling
The bitmap scaling sample application demonstrates how to scale the size of a Bitmap image.
The sample application demostrates how to scale an original Bitmap image into new Bitmap objects, how to apply filters that help reduce the pixelated appearance of a scaled Bitmap image, and how to preserve the aspect ratio of the image.
Custom Buttons
The custom buttons sample application demonstrates how to extend the Field class to create a variety of different button UI components.
The sample application demonstrates how to create the following types of buttons:
- rectangle
- triangle
- octagon
- rectangle with a fixed width
- rectangle with a fixed width and a long text label
- rectangle with a full screen width
- rectangle with a color background
- rectangle with a .bmp image as the background
In addition to creating and displaying these custom buttons, the sample application also demonstrates how to attach listeners to these custom buttons. Listeners are components that execute code when an event occurs. In the sample application, when you click one of these buttons, a dialog box appears with text specifying which of the buttons you clicked.
Decor
The decor sample application demonstrates how to create custom fields by specifying their border, padding, color, and background attributes.
You can use the sample application to create fields that have the following attributes:
- solid rounded border with a solid background
- dotted rounded border with a transparent background
- dashed simple border with a gradient background
- dotted simple border with no padding
- beveled border with an image as a background
Eyelid Field Manager
The eyelid field sample application demonstrates how to use the EyelidFieldManager class to display fields on a pair of managers that appear temporarily at the top and bottom of the screen.
When a BlackBerry® device user moves the trackpad or trackball, or when the user touches the screen (on aBlackBerry device with a touch screen), the managers are displayed temporarily on the top and bottom of the screen. While the managers are visible, the user can interact with the fields that appear on each manager. The user can also control the appearance of the managers by selecting or clearing check boxes that appear in the center of the screen.
For more information about displaying fields and managers in a BlackBerry device application, see the UI and Navigation Development Guide.
File Picker
The file picker sample application demonstrates how to create a UI component that presents a list of folders and files from which a user can select a file. The sample application also demonstrates how to specify the default search location for folders and how to filter files by file extension (for example, how to display only .mp3 files).
GPS
The GPS sample application implements a travel calculator that tracks the current location (using longitude, latitude, and altitude), direction, grade, and travel speed.
The GPS sample application uses the LocationProvider API to collect the GPS location information from theBlackBerry® device.
The sample application displays the information nearly simultaneously and updates the information at intervals that constants in the application specify.
The sample application also stores waypoints in persistent storage. These waypoints are recorded at intervals that constants in the application specify. The waypoints record the date and time they were taken, the distance travelled (using longitude, latitude, and altitude), and the average speed since the last waypoint.
HTTP push
The HTTP push sample application demonstrates how to push content to a BlackBerry® device and how to listen for pushed content on a BlackBerry device.
The sample application provides both a server-side application that you can use to send content to a BlackBerry Smartphone Simulator or BlackBerry device and a client-side application that listens for pushed content on aBlackBerry device.
Media Keys
The Media Keys sample application is a MIDlet that demonstrates how to respond to media key-press events on aBlackBerry® device. Media keys control the playback of music, video, and pictures that are stored on the device. The sample application is designed to accept media key presses while running in either the foreground or background.
The sample application highlights the use of the MediaBehaviourControl interface, which enables a MIDlet to act as a media player. For more information about monitoring media key-press events using the BlackBerry Java® API, see the Multimedia Development Guide.
