BufferedCanvasComponent.java 文件源码

public void hierarchyChanged(HierarchyEvent e) {
    if ((e.getChangeFlags() & HierarchyEvent.PARENT_CHANGED) != 0) {
        Window parentWindow = SwingUtilities.getWindowAncestor(BufferedCanvasComponent.this);
        if (lastParentWindow != parentWindow) {
            if (lastParentWindow != null) lastParentWindow.removeWindowListener(VisibilityHandler.this);
            if (parentWindow != null) parentWindow.addWindowListener(VisibilityHandler.this);
            lastParentWindow = parentWindow;
        }
    }

    if ((e.getChangeFlags() & HierarchyEvent.SHOWING_CHANGED) != 0) {
        if (isShowing()) BufferedCanvasComponent.this.shown();
        else BufferedCanvasComponent.this.hidden();
    }
}