Swing: column-flow layout manager?

问题

I'm looking for a LayoutManager that will allow me to show a set of components in a container (e.g. a JPanel), in columns, roughly as follows.

The container's width is an input constraint.
The container's preferred height is a function of the width, and is either:
- the minimum height needed to get the components to fit within the width, when laid out in more than one column.
- the minimum height needed to get the components to fit in a single column.
The components will be placed in a newspaper-column order, from top to bottom and then from left to right.

Here's an example (low-tech text display) showing 13 components. If they can fit in 3 columns, they would look like this:

Foo1    Foo6     Foo11   
Foo2    Foo7     Foo12
Foo3    Foo8     Foo13
Foo4    Foo9     
Foo5    Foo10

If that's too wide, they'd look like this:

Foo1    Foo8 
Foo2    Foo9  
Foo3    Foo10 
Foo4    Foo11 
Foo5    Foo12
Foo6    Foo13
Foo7

And if that's too wide, they'd look like this:

Foo1     
Foo2      
Foo3     
Foo4     
Foo5    
Foo6    
Foo7    
Foo8
Foo9
Foo10
Foo11
Foo12
Foo13

Is there a pre-existing LayoutManager that I can use or subclass to do something like this?

edit: this is very close to this other question about vertical layout, but that layout has the component height being the constraint, and mine has the component width being a constraint.

回答1:

One other component that admits this kind of layout is JList, which includes a VERTICAL_WRAP that "Indicates a newspaper style layout with cells flowing vertically then horizontally." Depending on your needs, a suitable ListCellRenderer, mentioned here, may be suffice.

回答2:

you might want to look into GribBagLayout http://download.oracle.com/javase/tutorial/uiswing/layout/gridbag.html

With gridbag layout knowing the size you can set how many components you would have in a particular row.

but if i am not mistaken shouldnt gridlayout do exactly what you want.

lets go with the simple labels. if the size*2 of the label is longer than the width, then it will show only 1 label per row. and so on.

here is an example which should clear it up

import java.awt.*;
import java.awt.event.*;

import javax.swing.*;

public class GridLayoutDemo implements ActionListener{
    JTextField j1;
    JTextField j2;
    JFrame f;
    public void show(){
        j1=new JTextField("x dimention");
        j2=new JTextField("y dimention");
        f=new JFrame();
        JPanel p=new JPanel();
        JLabel l2=new JLabel("abcdefghijklmnoqrstuvw");
        JLabel l1=new JLabel("abcdefghijklmnoqrstuvw");
        JLabel l3=new JLabel("abcdefghijklmnoqrstuvw");
        JLabel l4=new JLabel("abcdefghijklmnoqrstuvw");
        JButton b=new JButton("new size");
        b.addActionListener(this);

        p.add(l1);
        p.add(l2);
        p.add(l3);
        p.add(l4);
        p.add(j1);
        p.add(j2);
        p.add(b);
        f.setSize(400, 200);
        f.add(p);

        //f.pack();
        f.setVisible(true);

    }

    public static void main(String[] args){
        GridLayoutDemo g=new GridLayoutDemo();
        g.show();
    }
    @Override
    public void actionPerformed(ActionEvent arg0) {
        // TODO Auto-generated method stub
        int x=Integer.parseInt(j1.getText());
        int y=Integer.parseInt(j2.getText());
        f.setSize(x,y);
        f.setVisible(true);

    }
}

来源：https://stackoverflow.com/questions/6311772/swing-column-flow-layout-manager

标签

java

swing

layout-manager