Button is a control
for user to switch on or off as the input to the application.
Although Button is a
simple control, it can have many different appearances. With PocketC, you can
create push buttons, radio buttons, check boxes, and group boxes.
Push button is the
default button appearance. The styles
are BS_PUSHBUTTON and BS_DEFPUSHBUTTON.
BS_PUSHBUTTON will simply be a default button shape. BS_DEFPUSHBUTTON means the button is the
default button. It is drawn with a
heavy black rectangle around the button.
When users click the Enter key, the default button is pressed.
When a button is
pressed, an event will be returned from event() function. Its value is 8. We define PM_COMMAND as 8.
When we mention PM_COMMAND in other documentation, it means value
8. PM stands for Pocket Message. In order to find out which button has been
pressed, programmer must call guiid() to obtain the button control ID which was
pressed.
Check box is a square
with a user-defined label. User can
select a state by click on the square. Four variations of check boxes are
standard, automatic standard, three-state and automatic three-state.
BS_CHECKBOX is the
standard style. BS_AUTOCHECKBOX is same
as the standard style, except the Checkbox State is automatically switched
between checked and unchecked.
BS_3STATE and BS_AUTO3STATE have one more intermediate state between
checked and unchecked. A gray cross mark in the square indicates the extra
state.
By default, the
checkbox is displayed on the left side of the label. Style BS_RIGHTBUTTON will set the checkbox to the right side of
the label.
Radio button is
appears with a small round circle with user-defined text on its right. It has fewer states than the Checkbox
control. BS_RADIOBUTTON indicates the
standard style. BS_AUTORADIOBUTTON
behaves just like the automatically switched Checkbox button, except appears
differently.
In addition to all
the button styles we have discussed, there is one more feature of the button
control. It is Group Boxes style. By using BS_GROUPBOX, it draws a rectangle
with label displayed on its upper left corner.
Its sole purpose is to organize all the buttons on the screen by
grouping certain buttons together with rectangles.
Following example
shows how to display all types of buttons.
When a user clicks on any buttons, the edit box control will display the
name of the button control.
/*
Interface Control -- Window */
#define WS_CHILD 0x40000000
/*Specifies a child window. This
should not be changed after the window is created.*/
#define WS_VISIBLE 0x10000000
/*Specifies a window that is initially
visible. This style can be turned on and off to change window visibility.*/
#define WS_BORDER 0x00800000
/*draw a border around the control*/
/*
Interface Control -- Button */
#define BS_3STATE 0x0005
#define BS_AUTO3STATE 0x0006
#define BS_AUTOCHECKBOX 0x0003
#define BS_AUTORADIOBUTTON 0x0009
#define BS_CHECKBOX 0x0002
#define BS_DEFPUSHBUTTON 0x0001
#define BS_GROUPBOX 0x0007
#define BS_PUSHBUTTON 0x0000
#define BS_RADIOBUTTON 0x0004
#define BS_BOTTOM 0x0800
#define BS_CENTER 0x0300
#define BS_FLAT 0x8000
#define BS_LEFT 0x0100
#define BS_PUSHLIKE 0x1000
#define BS_RIGHT 0x0200
#define BS_RIGHTBUTTON 0x0100
#define BS_TOP 0x0400
#define BS_VCENTER 0x0C00
#define PM_COMMAND 8
/* custom define values */
#define BTN_PUSH_ID 601
#define BTN_RADIO_ID 602
#define BTN_CHECKBOX_ID 603
#define BTN_GROUPBOX_ID 604
#define ED_MONITOR_ID 600
main()
{
int ev; int gui_msg;
createctrl("EDIT","",WS_BORDER|WS_CHILD|WS_VISIBLE,0,50,30,150,20,
ED_MONITOR_ID);
createctrl("BUTTON","Push",WS_VISIBLE|WS_CHILD|WS_BORDER|BS_PUSHBUTTON,0,50,75,100,20,
BTN_PUSH_ID);
createctrl("BUTTON","Radio",WS_VISIBLE|WS_CHILD|BS_AUTORADIOBUTTON,0,50,100,100,20,
BTN_RADIO_ID);
createctrl("BUTTON","Checkbox",WS_VISIBLE|WS_CHILD|BS_AUTOCHECKBOX,0,50,125,100,20,
BTN_CHECKBOX_ID);
createctrl("BUTTON","Groupbox",WS_VISIBLE|WS_CHILD|BS_GROUPBOX,0,50,150,100,60,
BTN_GROUPBOX_ID);
while(1)
{
ev = event(0);
switch (ev){
case PM_COMMAND :
gui_msg
= guiid();
switch (gui_msg)
{
case BTN_PUSH_ID:
editset(ED_MONITOR_ID,"PushButton");
break;
case BTN_RADIO_ID:
editset(ED_MONITOR_ID,"RadioButton");
break;
case BTN_CHECKBOX_ID:
editset(ED_MONITOR_ID,"CheckBox");
break;
};
break;
};
}
}
BS_3STATE 0x0005 /*Creates a button that is the same as a
check box, except that the box can be grayed as well as checked or unchecked.
Use the grayed state to show that the state of the check box is not
determined.*/
BS_AUTO3STATE 0x0006 /*Creates a button that is the same as a
three-state check box, except that the box changes its state when the user
selects it. The state cycles through checked, grayed, and unchecked.*/
BS_AUTOCHECKBOX 0x0003 /*Creates a button that is the same as a
check box, except that the check state automatically toggles between checked
and unchecked each time the user selects the check box.*/
BS_AUTORADIOBUTTON 0x0009 /*Creates a button that is the same as a
radio button, except that when the user selects it, The system automatically
sets the button's check state to checked and automatically sets the check state
for all other buttons in the same group to unchecked.*/
BS_CHECKBOX 0x0002 /*Creates a small, empty check box with
text. By default, the text is displayed to the right of the check box. To
display the text to the left of the check box, combine this flag with the
BS_LEFTTEXT style (or with the equivalent BS_RIGHTBUTTON style).*/
BS_DEFPUSHBUTTON 0x0001 /*Creates a push button that behaves like
a BS_PUSHBUTTON style button, but also has a heavy black border. If the button
is in a dialog box, the user can select the button by pressing the enter key,
even when the button does not have the input focus. This style is useful for
enabling the user to quickly select the most likely (default) option.*/
BS_GROUPBOX 0x0007 /*Creates a rectangle in which other
controls can be grouped. Any text associated with this style is displayed in
the rectangle's upper left corner.*/
BS_PUSHBUTTON 0x0000 /*Creates a push button that posts a
WM_COMMAND message to the owner window when the user selects the button.*/
BS_RADIOBUTTON 0x0004 /*Creates a small circle with text. By
default, the text is displayed to the right of the circle. To display the text
to the left of the circle, combine this flag with the BS_LEFTTEXT style (or
with the equivalent BS_RIGHTBUTTON style). Use radio buttons for groups of
related, but mutually exclusive choices.*/
BS_BOTTOM 0x0800 /*Places text at the bottom of the button
rectangle.*/
BS_CENTER 0x0300 /*Centers text horizontally in the button
rectangle.*/
BS_FLAT 0x8000 /*Specifies that the button is
two-dimensional; it does not use the default shading to create a 3-D image.*/
BS_LEFT 0x0100 /*Left-justifies the text in the button
rectangle. However, if the button is a check box or radio button that does not
have the BS_RIGHTBUTTON style, the text is left justified on the right side of
the check box or radio button.*/
BS_PUSHLIKE 0x1000 /*Makes a button (such as a check box,
three-state check box, or radio button) look and act like a push button. The
button looks raised when it isn't pushed or checked, and sunken when it is
pushed or checked.*/
BS_RIGHT 0x0200 /*Right-justifies text in the button
rectangle. However, if the button is a check box or radio button that does not
have the BS_RIGHTBUTTON style, the text is right justified on the right side of
the check box or radio button.*/
BS_RIGHTBUTTON 0x0100 /*Positions a radio button's circle or a
check box's square on the right side of the button rectangle. Same as the
BS_LEFTTEXT style.*/
BS_TOP 0x0400 /*Places
text at the top of the button rectangle.*/
BS_VCENTER 0x0C00 /*Places text in the middle (vertically)
of the button rectangle.*/