好的，这就是我最终得到的结果（处理奇怪边缘情况的代码墙）。
correctWindowLocationForScreen() 将重新定位一个窗口，如果它不完全在可见屏幕区域内（最简单的情况，它完全在一个屏幕上。硬情况，它跨越多个屏幕）。如果窗口仅离开整个屏幕区域一个像素，则使用找到的第一个屏幕矩形重新定位。如果窗口不适合屏幕，它位于左上角并延伸到屏幕右下角（它由 positionInsideRectangle() 检查/更改坐标的顺序暗示）。
考虑到需求很简单，这很复杂。
/**
* Check that window is completely on screen, if not correct position.
* Will not ensure the window fits completely onto the screen.
*/
public static void correctWindowLocationForScreen(final Window window) {
correctComponentLocation(window, getScreenRectangles());
}
/**
* Set the component location so that it is completely inside the available
* regions (if possible).
* Although the method will make some effort to place the component
* nicely, it may end up partially outside the regions (either because it
* doesn't fit at all, or the regions are placed badly).
*/
public static void correctComponentLocation(final Component component, final Rectangle ... availableRegions) {
// check the simple cases (component completely inside one region, no regions available)
final Rectangle bounds = component.getBounds();
if (availableRegions == null || availableRegions.length <= 0)
return;
final List<Rectangle> intersecting = new ArrayList<>(3);
for (final Rectangle region : availableRegions) {
if (region.contains(bounds)) {
return;
} else if (region.intersects(bounds)) {
// partial overlap
intersecting.add(region);
}
}
switch (intersecting.size()) {
case 0:
// position component in the first available region
positionInsideRectangle(component, availableRegions[0]);
return;
case 1:
// position component in the only intersecting region
positionInsideRectangle(component, intersecting.get(0));
return;
default:
// uuuh oooh...
break;
}
// build area containing all detected intersections
// and check if the bounds fall completely into the intersection area
final Area area = new Area();
for (final Rectangle region : intersecting) {
final Rectangle2D r2d = new Rectangle2D.Double(region.x, region.y, region.width, region.height);
area.add(new Area(r2d));
}
final Rectangle2D boundsRect = new Rectangle2D.Double(bounds.x, bounds.y, bounds.width, bounds.height);
if (area.contains(boundsRect))
return;
// bah, just place it in the first intersecting region...
positionInsideRectangle(component, intersecting.get(0));
}
/**
* Position component so that its completely inside the rectangle.
* If the component is larger than the rectangle, component will
* exceed to rectangle bounds to the right and bottom, e.g.
* the component is placed at the rectangles x respectively y.
*/
public static void positionInsideRectangle(final Component component, final Rectangle region) {
final Rectangle bounds = component.getBounds();
int x = bounds.x;
int y = bounds.y;
if (x + bounds.width > region.x + region.width)
x = region.x + region.width - bounds.width;
if (y + bounds.height > region.y + region.height)
y = region.y + region.height - bounds.height;
if (region.x < region.x)
x = region.x;
if (y < region.y)
y = region.y;
if (x != bounds.x || y != bounds.y)
component.setLocation(x, y);
}
/**
* Gets the available display space as an arrays of rectangles
* (there is one rectangle for each screen, if the environment is
* headless the resulting array will be empty).
*/
public static Rectangle[] getScreenRectangles() {
try {
Rectangle[] result;
final GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
final GraphicsDevice[] devices = ge.getScreenDevices();
result = new Rectangle[devices.length];
for (int i=0; i<devices.length; ++i) {
final GraphicsDevice gd = devices[i];
result[i] = gd.getDefaultConfiguration().getBounds();
}
return result;
} catch (final Exception e) {
return new Rectangle[0];
}
}