Forms

A canvas is a place to hold the objects. The four types of canvases are: Content, Stacked, Tab, and Toolbar. All can coexist within a single window. A content canvas is the basic background for all windows. A stacked canvas lays on top of the others. A tab canvas is the same as stacked canvases with handy �tabs� at the top. It can simply move from one canvas to another. A toolbar canvas contains push buttons giving users quick access such as horizontal canvas or vertical canvas.

A Horizontal Toolbar canvas contains buttons that give you quick access to your application functions. They would be activated by your defined triggers.

New functional requirements came in from the users. They need a horizontal toolbar to have on their Form. The toolbar should contain all the frequently used options. This will make ease of use of some options.

The following are the list of all the frequently used functions they expect to use:

Move to previous record,

Move to next record,

Add new record,

Delete current record,

Save work, and

Exit the application.

See Figure 9.

Your tasks are:

1- Adding more functionality to the application.

2- Create a horizontal Toolbar.

3- Create push button for above frequently used functions list.

4- Create and compile triggers for each push button created on step 3.

5- Run and test all user functional requirements.

You will learn how to: create and use horizontal toolbar, create and use the push button item, create the "WHEN-BUTTON-PRESSED" trigger, write and compile trigger, use tab canvas, use �object navigator,� use �Data Blocks,� use �Layout Editor,� use �Property Palette,� use �Run Form,� and �Execute Query.�

Figure 9

In the �Object Navigator� window, highlight Forms. Go to the Main menu and choose �File,� select �Open� to open an existing form (customer_orders_V06) in the folder.

Click on the �CUSTOMER_ORDERS_V06� form. The color will change to blue. Now, change the name and then save the Form name as version 07 (customer_orders_v07). This way the original form is untouched.

To create more canvas, go to the Object Navigator window and highlight the Canvases item. Click on the green �+� sign in the toolbar in the Object Navigator. A canvas will be created for you (CANVASnn). The nn could be any Oracle assigned number.

Right click on it and open its Property Palette. Change �name� to "PB_BLOCK.� The PB stand for Push Button Block. Change "Canvas type" to "Horizontal toolbar." Check the icon next to it changed in the Object Navigator. Close the window.

In the Layout Editor click on the Down Arrow next to the Canvas box to select new canvas (PB_BLOCK).

Notice that, it is too big to be the "horizontal toolbar" canvas. Change the size. Notice that you will see two boarders one is white and the other block. Let see if you only drag the black boarder. Check the picture to see how your horizontal tool bar is going to be.

Navigate through these two canvases.

In the Layout Editor, highlight the �Data Blocks� and click on the green �+� sign to create a new data block.

In the �New Data Block� window, don�t choose the default option. Select the �Build a new data block manually� and click "OK."

Right click on it and open its Property Palette. In the Property Palette window, change the Name value to �PB_BLOCK.� Change "Database Data Block" to �NO.� Then close the window.

In the Layout Editor, while the Canvas value is PB_BLOCK and the Block value is PB_BLOCK, click on the PUSH BUTTON icon on the toolbar and drag the �+� sign on the PB_BLOCK canvas and click where you wish to have your Push Button.

Copy the object and paste it five times. The copy will be pasted on the top of each other. You need to select them one by one and drag them to be next to each others. Now, you should have six push buttons.

Right click on the first push button object and open its property palette. Change "name" to �PREV_REC.� Blank the "label." Set �iconic� to "yes." On �Icon Filename,� type "w_prev." This is an oracle reserve word and could be different version to version. Change "Keyboard Navigators" and "Mouse Navigators� to �NO.� Then close the window.

Repeat the process for the rest of the push button items.

Only change the name and the Icon Filename.

Change name to NEXT_REC.

On �Icon Filename,� use "w_next" for next record.

Change name to ADD_REC.

On �Icon Filename,� use "addrow" for adding a record.

Change name to DEL_REC.

On �Icon Filename,� use "delrow" for deleting a record.

Change name to SAVE.

On �Icon Filename,� use "save" for saving the application transactions.

Change name to EXIT.

On �Icon Filename,� use "exit" for exiting the application.

While holding the control key, click on the objects you want to select. And then right click to open their property palette.

Change �height� to 20 and press the enter key.

Close the window.

Make some layout adjustments if needed.

Notice that these push buttons have no functionality.

Expand the PB_BLOCK data block. Expand the ITEMS object. All the items in the PB_BLOCK data block will be displayed. Notice that the box next to Trigger is empty for all the items in the data block. That means they don�t have any triggers.

For each item, highlight the Trigger item and click on the green �+� sign on the toolbar in the Object Navigator window to create a trigger.

In the Trigger window, type a letter �W� and you will see all the triggers that start with the letter �W.� Select the �WHEN-BUTTON-PRESSED� trigger.

In the PL/SQL Editor window, write a query for a record to navigate to a previous record.

(PL/SQL Editor)

Compile it.

Repeat this process for all the other triggers.

For NEXT_REC:

(PL/SQL Editor)

For ADD_REC:

(PL/SQL Editor)

For DEL_REC:

(PL/SQL Editor)

For SAVE:

(PL/SQL Editor)

For EXIT:

(PL/SQL Editor)

Notice on different ways of doing this.

Check the application layout.

Then run the application.

Here, the only canvas you can see is: the horizontal toolbar canvas. There is no indication of the other canvas. You should drag the window to see the other canvas.

You can either close the window or drag to resize the window to use the �Customer�s Order� application. Resize the window and execute the query.

Test the push button functionality. After the testing is done, close the window and save the changes.

The canvas should not be small and user will not like to drag the window to see other data information. In the next hands-on exercise, we will learn how to avoid such problem and why we were getting that.

Q: Describe a canvas in the Form Module.

Q: The four types of canvases are: ________

Q: Describe all four types of canvases.

Q: How do you create a horizontal toolbar?

Q: How do you create a push button item?

Q: New functional requirements came in from the users. They need a horizontal toolbar to have on their Form. The toolbar should contain all the frequently used options. This will make ease of use of some options.

The following are the list of all the frequently used functions they expect to use:

Move to previous record,

Move to next record,

Add new record,

Delete current record,

Save work, and

Exit the application.

See Figure 9.

Your tasks are:

1- Adding more functionality to the application.

2- Create a horizontal Toolbar.

3- Create push button for above frequently used functions list.

4- Create and compile triggers for each push button created on step 3.

5- Run and test all user functional requirements.