columnlayout.java

corejava的一部分源码,与corejiavasource中的有区别。

import java.awt.*;

public class ColumnLayout implements LayoutManager {
    static private int _defaultGap = 5;

    private int         gap;
    private Orientation horizontalOrientation;
    private Orientation verticalOrientation;

    public ColumnLayout() {
        this(Orientation.CENTER, 
             Orientation.CENTER, _defaultGap);
    }
    public ColumnLayout(int gap) {
        this(Orientation.CENTER, Orientation.CENTER, gap);
    }
    public ColumnLayout(Orientation horizontalOrient, 
                        Orientation verticalOrient) {
        this(horizontalOrient, verticalOrient, _defaultGap);
    }
    public ColumnLayout(Orientation horizontalOrient, 
                        Orientation verticalOrient, int gap) {
        if(gap < 0 ||
            (horizontalOrient != Orientation.LEFT   &&
            horizontalOrient != Orientation.CENTER &&
            horizontalOrient != Orientation.RIGHT) ||

            (verticalOrient   != Orientation.TOP    &&
            verticalOrient   != Orientation.CENTER &&
            verticalOrient   != Orientation.BOTTOM)) {
			throw new IllegalArgumentException(
				"bad gap or orientation");
		}
        this.gap                   = gap;
        this.verticalOrientation   = verticalOrient;
        this.horizontalOrientation = horizontalOrient;
    }

    public void addLayoutComponent(String name, 
                                   Component comp) {
    }
    public void removeLayoutComponent(Component comp) { 
    }

    public Dimension preferredLayoutSize(Container target) {
        Insets    insets      = target.getInsets();
        Dimension dim         = new Dimension(0,0);
        int       ncomponents = target.getComponentCount();
        Component comp;
        Dimension d;

        for (int i = 0 ; i < ncomponents ; i++) {
            comp = target.getComponent(i);

            if(comp.isVisible()) {
                d = comp.getPreferredSize();
                if(i > 0) 
                    dim.height += gap;

                dim.height += d.height;
                dim.width   = Math.max(d.width, dim.width);
            }
        }
        dim.width  += insets.left + insets.right;
        dim.height += insets.top  + insets.bottom;
        return dim;
    }
    public Dimension minimumLayoutSize(Container target) {
        Insets    insets      = target.getInsets();
        Dimension dim         = new Dimension(0,0);
        int       ncomponents = target.getComponentCount();
        Component comp;
        Dimension d;

        for (int i = 0 ; i < ncomponents ; i++) {
            comp = target.getComponent(i);

            if(comp.isVisible()) {
                d = comp.getMinimumSize();

                dim.width  = Math.max(d.width, dim.width);
                dim.height += d.height;

                if(i > 0) dim.height += gap;
            }
        }
        dim.width  += insets.left + insets.right;
        dim.height += insets.top  + insets.bottom;

        return dim;
    }
    public void layoutContainer(Container target) {
        Insets    insets        = target.getInsets();
        int       top           = insets.top;
        int       left          = 0;
        int       ncomponents   = target.getComponentCount();
        Dimension preferredSize = target.getPreferredSize();
        Dimension targetSize    = target.getSize();
        Component comp;
        Dimension ps;

        if(verticalOrientation == Orientation.CENTER)
            top += (targetSize.height/2) - 
                   (preferredSize.height/2);
        else if(verticalOrientation == Orientation.BOTTOM)
            top = targetSize.height - preferredSize.height + 
                  insets.top;

        for (int i = 0 ; i < ncomponents ; i++) {
            comp = target.getComponent(i);
            left = insets.left;

            if(comp.isVisible()) {
                ps = comp.getPreferredSize();

                if(horizontalOrientation == Orientation.CENTER)
                    left = (targetSize.width/2) - (ps.width/2);
                else if(
                  horizontalOrientation == Orientation.RIGHT) {
                    left = targetSize.width - ps.width - 
                           insets.right;
                }
                comp.setBounds(left,top,ps.width,ps.height);
                top += ps.height + gap;
            }
        }
    }
}