Added Checkbox.Checked().

checkbox.go

@@ -39,7 +39,17 @@ func (c *Checkbox) SetText(text string) (err error) {
 	return nil
 }
 
-// TODO Checked()
+// Checked() returns whether or not the checkbox has been checked.
+func (c *Checkbox) Checked() bool {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+
+	check, err := c.sysData.isChecked()
+	if err != nil {
+		panic(err)		// TODO
+	}
+	return check
+}
 
 func (c *Checkbox) apply(window *sysData) error {
 	c.lock.Lock()

controls_windows.go

@@ -38,10 +38,25 @@ const (
 	_BS_FLAT = 0x00008000
 	_BS_RIGHTBUTTON = _BS_LEFTTEXT
 	// from commctrl.h
-//	_BS_SPLITBUTTON = 0x0000000C		// Windows Vista and newer and(/or?) comctl6 only
-//	_BS_DEFSPLITBUTTON = 0x0000000D	// Windows Vista and newer and(/or?) comctl6 only
+//	_BS_SPLITBUTTON = 0x0000000C			// Windows Vista and newer and(/or?) comctl6 only
+//	_BS_DEFSPLITBUTTON = 0x0000000D		// Windows Vista and newer and(/or?) comctl6 only
 //	_BS_COMMANDLINK = 0x0000000E		// Windows Vista and newer and(/or?) comctl6 only
-//	_BS_DEFCOMMANDLINK = 0x0000000F	// Windows Vista and newer and(/or?) comctl6 only
+//	_BS_DEFCOMMANDLINK = 0x0000000F		// Windows Vista and newer and(/or?) comctl6 only
+)
+
+// Button messages.
+// TODO check if any are not defined on Windows 2000
+const (
+	// from winuser.h
+	_BM_GETCHECK = 0x00F0
+	_BM_SETCHECK = 0x00F1
+	_BM_GETSTATE = 0x00F2
+	_BM_SETSTATE = 0x00F3
+	_BM_SETSTYLE = 0x00F4
+	_BM_CLICK = 0x00F5
+	_BM_GETIMAGE = 0x00F6
+	_BM_SETIMAGE = 0x00F7
+	_BM_SETDONTCLICK = 0x00F8
 )
 
 // Button WM_COMMAND notifications.

main.go

@@ -1,6 +1,10 @@
 // 11 february 2014
 package main
 
+import (
+	"fmt"
+)
+
 func main() {
 	w := NewWindow("Main Window", 320, 240)
 	w.Closing = make(chan struct{})
@@ -23,7 +27,7 @@ mainloop:
 		case <-w.Closing:
 			break mainloop
 		case <-b.Clicked:
-			err := w.SetTitle("Button Clicked")
+			err := w.SetTitle(fmt.Sprintf("Check State: %v", c.Checked()))
 			if err != nil {
 				panic(err)
 			}

sysdata.go

@@ -26,6 +26,9 @@ func (c *cSysData) setText(text string) error {
 func (c *cSysData) setRect(x int, y int, width int, height int) error {
 	panic(runtime.GOOS + " sysData does not define setRect()")
 }
+func (c *cSysData) isChecked() (bool, error) {
+	panic(runtime.GOOS + " sysData does not define isChecked()")
+}
 
 const (
 	c_window = iota

sysdata_windows.go

@@ -201,3 +201,21 @@ func (s *sysData) setRect(x int, y int, width int, height int) error {
 	}
 	return nil
 }
+
+// TODO figure out how to handle error
+func (s *sysData) isChecked() (bool, error) {
+	ret := make(chan uiret)
+	defer close(ret)
+	uitask <- &uimsg{
+		call:		_sendMessage,
+		p:		[]uintptr{
+			uintptr(s.hwnd),
+			uintptr(_BM_GETCHECK),
+			uintptr(0),
+			uintptr(0),
+		},
+		ret:		ret,
+	}
+	r := <-ret
+	return r.ret == _BST_CHECKED, nil
+}