slider.java

源码为Eclipse开源开发平台桌面开发工具SWT的源代码,

	if ((state & DISABLED) != 0) {
		if (OS.IsWinCE) {
			OS.EnableWindow (handle, false);
		} else {
			OS.EnableScrollBar (handle, OS.SB_CTL, OS.ESB_DISABLE_BOTH);
		}
	}
	
	/*
	* Bug in Windows.  If the thumb is resized when it has focus,
	* the flashing cursor that is used to show that the scroll bar has
	* focus is not moved.  The fix is to post a fake WM_SETFOCUS to
	* get the scroll bar to recompute the size of the flashing cursor.
	*/
	if (OS.GetFocus () == handle) {
		OS.PostMessage (handle, OS.WM_SETFOCUS, 0, 0);
	}
}

/**
 * Sets the minimum value. If this value is negative or greater
 * than or equal to the maximum, the value is ignored. If necessary,
 * first the thumb and then the selection are adjusted to fit within
 * the new range.
 *
 * @param value the new minimum
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setMinimum (int value) {
	checkWidget ();
	if (value < 0) return;
	SCROLLINFO info = new SCROLLINFO ();
	info.cbSize = SCROLLINFO.sizeof;
	info.fMask = OS.SIF_RANGE | OS.SIF_DISABLENOSCROLL;
	OS.GetScrollInfo (handle, OS.SB_CTL, info);
	if (info.nMax - value - info.nPage < 1) return;
	info.nMin = value;
	OS.SetScrollInfo (handle, OS.SB_CTL, info, true);

	/*
	* Feature in Windows.  Using SIF_DISABLENOSCROLL,
	* SetScrollInfo () can change enabled and disabled
	* state of the scroll bar causing a scroll bar that
	* was disabled by the application to become enabled.
	* The fix is to disable the scroll bar (again) when
	* the application has disabled the scroll bar.
	*/
	if ((state & DISABLED) != 0) {
		if (OS.IsWinCE) {
			OS.EnableWindow (handle, false);
		} else {
			OS.EnableScrollBar (handle, OS.SB_CTL, OS.ESB_DISABLE_BOTH);
		}
	}
	
	/*
	* Bug in Windows.  If the thumb is resized when it has focus,
	* the flashing cursor that is used to show that the scroll bar has
	* focus is not moved.  The fix is to post a fake WM_SETFOCUS to
	* get the scroll bar to recompute the size of the flashing cursor.
	*/
	if (OS.GetFocus () == handle) {
		OS.PostMessage (handle, OS.WM_SETFOCUS, 0, 0);
	}
}

/**
 * Sets the amount that the receiver's value will be
 * modified by when the page increment/decrement areas
 * are selected to the argument, which must be at least
 * one.
 *
 * @param value the page increment (must be greater than zero)
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setPageIncrement (int value) {
	checkWidget ();
	if (value < 1) return;
	pageIncrement = value;
}

/**
 * Sets the single <em>selection</em> that is the receiver's
 * value to the argument which must be greater than or equal
 * to zero.
 *
 * @param value the new selection (must be zero or greater)
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setSelection (int value) {
	checkWidget ();
	SCROLLINFO info = new SCROLLINFO ();
	info.cbSize = SCROLLINFO.sizeof;
	info.fMask = OS.SIF_POS;
	info.nPos = value;
	OS.SetScrollInfo (handle, OS.SB_CTL, info, true);
}

/**
 * Sets the size of the receiver's thumb relative to the
 * difference between its maximum and minimum values.  This new
 * value will be ignored if it is less than one, and will be
 * clamped if it exceeds the receiver's current range.
 *
 * @param value the new thumb value, which must be at least one and not
 * larger than the size of the current range
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setThumb (int value) {
	checkWidget ();

	/* Position the thumb */
	if (value < 1) return;
	SCROLLINFO info = new SCROLLINFO ();
	info.cbSize = SCROLLINFO.sizeof;
	info.fMask = OS.SIF_PAGE | OS.SIF_RANGE | OS.SIF_DISABLENOSCROLL;
	OS.GetScrollInfo (handle, OS.SB_CTL, info);
	info.nPage = value;
	if (info.nPage != 0) info.nPage++;
	OS.SetScrollInfo (handle, OS.SB_CTL, info, true);
		
	/*
	* Feature in Windows.  Using SIF_DISABLENOSCROLL,
	* SetScrollInfo () can change enabled and disabled
	* state of the scroll bar causing a scroll bar that
	* was disabled by the application to become enabled.
	* The fix is to disable the scroll bar (again) when
	* the application has disabled the scroll bar.
	*/
	if ((state & DISABLED) != 0) {
		if (OS.IsWinCE) {
			OS.EnableWindow (handle, false);
		} else {
			OS.EnableScrollBar (handle, OS.SB_CTL, OS.ESB_DISABLE_BOTH);
		}
	}
	
	/*
	* Bug in Windows.  If the thumb is resized when it has focus,
	* the flashing cursor that is used to show that the scroll bar has
	* focus is not moved.  The fix is to post a fake WM_SETFOCUS to
	* get the scroll bar to recompute the size of the flashing cursor.
	*/
	if (OS.GetFocus () == handle) {
		OS.PostMessage (handle, OS.WM_SETFOCUS, 0, 0);
	}
}

/**
 * Sets the receiver's selection, minimum value, maximum
 * value, thumb, increment and page increment all at once.
 * <p>
 * Note: This is equivalent to setting the values individually
 * using the appropriate methods, but may be implemented in a 
 * more efficient fashion on some platforms.
 * </p>
 *
 * @param selection the new selection value
 * @param minimum the new minimum value
 * @param maximum the new maximum value
 * @param thumb the new thumb value
 * @param increment the new increment value
 * @param pageIncrement the new pageIncrement value
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setValues (int selection, int minimum, int maximum, int thumb, int increment, int pageIncrement) {
	checkWidget ();
	if (minimum < 0) return;
	if (maximum < 0) return;
	if (thumb < 1) return;
	if (increment < 1) return;
	if (pageIncrement < 1) return;
	this.increment = increment;
	this.pageIncrement = pageIncrement;
	SCROLLINFO info = new SCROLLINFO ();
	info.cbSize = SCROLLINFO.sizeof;
	info.fMask = OS.SIF_POS | OS.SIF_PAGE | OS.SIF_RANGE | OS.SIF_DISABLENOSCROLL;
	info.nPos = selection;
	info.nMin = minimum;
	info.nMax = maximum;
	info.nPage = thumb;
	if (info.nPage != 0) info.nPage++;
	OS.SetScrollInfo (handle, OS.SB_CTL, info, true);
		
	/*
	* Feature in Windows.  Using SIF_DISABLENOSCROLL,
	* SetScrollInfo () can change enabled and disabled
	* state of the scroll bar causing a scroll bar that
	* was disabled by the application to become enabled.
	* The fix is to disable the scroll bar (again) when
	* the application has disabled the scroll bar.
	*/
	if ((state & DISABLED) != 0) {
		if (OS.IsWinCE) {
			OS.EnableWindow (handle, false);
		} else {
			OS.EnableScrollBar (handle, OS.SB_CTL, OS.ESB_DISABLE_BOTH);
		}
	}
	
	/*
	* Bug in Windows.  If the thumb is resized when it has focus,
	* the flashing cursor that is used to show that the scroll bar has
	* focus is not moved.  The fix is to post a fake WM_SETFOCUS to
	* get the scroll bar to recompute the size of the flashing cursor.
	*/
	if (OS.GetFocus () == handle) {
		OS.PostMessage (handle, OS.WM_SETFOCUS, 0, 0);
	}
}

int widgetExtStyle () {
	/*
	* Bug in Windows.  If a scroll bar control is given a border,
	* dragging the scroll bar thumb eats away parts of the border 
	* while the thumb is dragged.  The fix is to clear border for
	* all scroll bars.
	*/
	int bits = super.widgetExtStyle ();
	if ((style & SWT.BORDER) != 0) bits &= ~OS.WS_EX_CLIENTEDGE;
	return bits;
}

int widgetStyle () {
	int bits = super.widgetStyle () | OS.WS_TABSTOP;
	/*
	* Bug in Windows.  If a scroll bar control is given a border,
	* dragging the scroll bar thumb eats away parts of the border 
	* while the thumb is dragged.  The fix is to clear WS_BORDER.
	*/
	if ((style & SWT.BORDER) != 0) bits &= ~OS.WS_BORDER;
	if ((style & SWT.HORIZONTAL) != 0) return bits | OS.SBS_HORZ;
	return bits | OS.SBS_VERT;
}

TCHAR windowClass () {
	return ScrollBarClass;
}

int windowProc () {
	return ScrollBarProc;
}

LRESULT WM_KEYDOWN (int wParam, int lParam) {
 	LRESULT result = super.WM_KEYDOWN (wParam, lParam);
 	if (result != null) return result;
 	if ((style & SWT.VERTICAL) != 0) return result;
 	
 	/*
 	* Bug in Windows.  When a horizontal scroll bar is mirrored,
 	* the native control does not correctly swap the arrow keys.
 	* The fix is to swap them before calling the scroll bar window
 	* proc.
 	* 
 	* NOTE: This fix is not ideal.  It breaks when the bug is fixed
 	* in the operating system.
 	*/
	if ((style & SWT.MIRRORED) != 0) {
	 	switch (wParam) {
	 		case OS.VK_LEFT: 
			case OS.VK_RIGHT: {
				int key = wParam == OS.VK_LEFT ? OS.VK_RIGHT : OS.VK_LEFT;
				int code = callWindowProc (OS.WM_KEYDOWN, key, lParam);
	 			return new LRESULT (code);
	 		}
	 	}
	}
 	return result;
}
 
LRESULT WM_LBUTTONDBLCLK (int wParam, int lParam) {
	
	/*
	* Feature in Windows.  For some reason, capturing
	* the mouse after processing WM_LBUTTONDBLCLK for the
	* widget interferes with the normal mouse processing
	* for the widget.  The fix is to avoid the automatic
	* mouse capture.
	*/

	/*
	* Feature in Windows.  Windows uses the WS_TABSTOP
	* style for the scroll bar to decide that focus
	* should be set during WM_LBUTTONDBLCLK.  This is
	* not the desired behavior.  The fix is to clear
	* and restore WS_TABSTOP so that Windows will not
	* assign focus.
	*/

	int hwndCapture = OS.GetCapture ();
	int oldBits = OS.GetWindowLong (handle, OS.GWL_STYLE);
	int newBits = oldBits & ~OS.WS_TABSTOP;
	OS.SetWindowLong (handle, OS.GWL_STYLE, newBits);	
	LRESULT result = super.WM_LBUTTONDBLCLK (wParam, lParam);
	OS.SetWindowLong (handle, OS.GWL_STYLE, oldBits);
	if (OS.GetCapture () != hwndCapture) OS.SetCapture (hwndCapture);
	
	/*
	* Feature in Windows.  Windows runs a modal message loop
	* when the user drags a scroll bar that terminates when
	* it sees an WM_LBUTTONUP.  Unfortunately the WM_LBUTTONUP
	* is consumed.  The fix is to send a fake mouse up.
	*/	
	sendMouseEvent (SWT.MouseUp, 1, OS.WM_LBUTTONUP, wParam, lParam);	
	return result;
}

LRESULT WM_LBUTTONDOWN (int wParam, int lParam) {
	
	/*
	* Feature in Windows.  For some reason, capturing
	* the mouse after processing WM_LBUTTONDOWN for the
	* widget interferes with the normal mouse processing
	* for the widget.  The fix is to avoid the automatic
	* mouse capture.
	*/

	/*
	* Feature in Windows.  Windows uses the WS_TABSTOP
	* style for the scroll bar to decide that focus
	* should be set during WM_LBUTTONDOWN.  This is
	* not the desired behavior.  The fix is to clear
	* and restore WS_TABSTOP so that Windows will not
	* assign focus.
	*/

	int hwndCapture = OS.GetCapture ();
	int oldBits = OS.GetWindowLong (handle, OS.GWL_STYLE);
	int newBits = oldBits & ~OS.WS_TABSTOP;
	OS.SetWindowLong (handle, OS.GWL_STYLE, newBits);	
	LRESULT result = super.WM_LBUTTONDOWN (wParam, lParam);
	OS.SetWindowLong (handle, OS.GWL_STYLE, oldBits);
	if (OS.GetCapture () != hwndCapture) OS.SetCapture (hwndCapture);
	
	/*
	* Feature in Windows.  Windows runs a modal message loop
	* when the user drags a scroll bar that terminates when
	* it sees an WM_LBUTTONUP.  Unfortunately the WM_LBUTTONUP
	* is consumed.  The fix is to send a fake mouse up.
	*/	
	sendMouseEvent (SWT.MouseUp, 1, OS.WM_LBUTTONUP, wParam, lParam);
	return result;
}

LRESULT wmScrollChild (int wParam, int lParam) {

	/* Do nothing when scrolling is ending */
	int code = wParam & 0xFFFF;
	if (code == OS.SB_ENDSCROLL) return null;

	/* Move the thumb */
	Event event = new Event ();
	SCROLLINFO info = new SCROLLINFO ();
	info.cbSize = SCROLLINFO.sizeof;
	info.fMask = OS.SIF_TRACKPOS | OS.SIF_POS | OS.SIF_RANGE;
	OS.GetScrollInfo (handle, OS.SB_CTL, info);
	info.fMask = OS.SIF_POS;
	switch (code) {
		case OS.SB_THUMBPOSITION:
			/*
			* Do not set the detail field to DRAG to
			* indicate that the dragging has ended.
			*/
			info.nPos = info.nTrackPos;
			break;
		case OS.SB_THUMBTRACK:
			event.detail = SWT.DRAG;
			info.nPos = info.nTrackPos;
			break;
		case OS.SB_TOP:
			event.detail = SWT.HOME;
			info.nPos = info.nMin;
			break;
		case OS.SB_BOTTOM:
			event.detail = SWT.END;
			info.nPos = info.nMax;
			break;
		case OS.SB_LINEDOWN:
			event.detail = SWT.ARROW_DOWN;
			info.nPos += increment;
			break;
		case OS.SB_LINEUP:
			event.detail = SWT.ARROW_UP;
			info.nPos = Math.max (info.nMin, info.nPos - increment);
			break;
		case OS.SB_PAGEDOWN:
			event.detail = SWT.PAGE_DOWN;
			info.nPos += pageIncrement;
			break;
		case OS.SB_PAGEUP:
			event.detail = SWT.PAGE_UP;
			info.nPos = Math.max (info.nMin, info.nPos - pageIncrement);
			break;
	}
	OS.SetScrollInfo (handle, OS.SB_CTL, info, true);
	
	/*
	* Feature in Windows.  Windows runs a modal message
	* loop when the user drags a scroll bar.  This means
	* that selection event must be sent because WM_HSCROLL
	* and WM_VSCROLL are sent from the modal message loop
	* so that they are delivered during inside the loop.
	*/
	sendEvent (SWT.Selection, event);
	// the widget could be destroyed at this point
	return null;
}

}