SWING – FlowLayout Class

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Introduction

The class FlowLayout components in a left-to-right flow.

Class Declaration

Following is the declaration for java.awt.FlowLayout class −

public class FlowLayout
   extends Object
      implements LayoutManager, Serializable

Field

Following are the fields for java.awt.BorderLayout class −

• static int CENTER − This value indicates that each row of components should be centered.

• static int LEADING − This value indicates that each row of components should be justified to the leading edge of the container’s orientation. For example, to the left in left-to-right orientations.

• static int LEFT − This value indicates that each row of components should be left-justified.

• static int RIGHT − This value indicates that each row of components should be right-justified.

• static int TRAILING − This value indicates that each row of components should be justified to the trailing edge of the container’s orientation. For example, to the right in left-to-right orientations.

Class Constructors

Sr.No.
Constructor & Description

1

FlowLayout()

Constructs a new FlowLayout with a centered alignment and a default 5-unit horizontal and vertical gap.

2

FlowLayout(int align)

Constructs a new FlowLayout with the specified alignment and a default 5-unit horizontal and vertical gap.

3

FlowLayout(int align, int hgap, int vgap)

Creates a new flow layout manager with the indicated alignment and the indicated horizontal and vertical gaps.

Class Methods

Sr.No.
Method & Description

1

void addLayoutComponent(String name, Component comp)

Adds the specified component to the layout.

2

int getAlignment()

Gets the alignment for this layout.

3

int getHgap()

Gets the horizontal gap between the components.

4

int getVgap()

Gets the vertical gap between the components.

5

void layoutContainer(Container target)

Lays out the container.

6

Dimension minimumLayoutSize(Container target)

Returns the minimum dimensions needed to layout the visible components contained in the specified target container.

7

Dimension preferredLayoutSize(Container target)

Returns the preferred dimensions for this layout given the visible components in the specified target container.

8

void removeLayoutComponent(Component comp)

Removes the specified component from the layout.

9

void setAlignment(int align)

Sets the alignment for this layout.

10

void setHgap(int hgap)

Sets the horizontal gap between the components.

11

void setVgap(int vgap)

Sets the vertical gap between the components.

12

String toString()

Returns a string representation of this FlowLayout object and its values.

Methods Inherited

This class inherits methods from the following classes −

• java.lang.Object

FlowLayout Example

Create the following Java program using any editor of your choice in say D:/ > SWING > com > tutorialspoint > gui >

SwingLayoutDemo.java

package com.tutorialspoint.gui;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class SwingLayoutDemo {
   private JFrame mainFrame;
   private JLabel headerLabel;
   private JLabel statusLabel;
   private JPanel controlPanel;
   private JLabel msglabel;

   public SwingLayoutDemo(){
      prepareGUI();
   }
   public static void main(String[] args){
      SwingLayoutDemo swingLayoutDemo = new SwingLayoutDemo();  
      swingLayoutDemo.showFlowLayoutDemo();       
   }
   private void prepareGUI(){
      mainFrame = new JFrame("Java SWING Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));

      headerLabel = new JLabel("",JLabel.CENTER );
      statusLabel = new JLabel("",JLabel.CENTER);        
      statusLabel.setSize(350,100);
      
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      controlPanel = new JPanel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }
   private void showFlowLayoutDemo(){
      headerLabel.setText("Layout in action: FlowLayout");      

      JPanel panel = new JPanel();
      panel.setBackground(Color.darkGray);
      panel.setSize(200,200);
      FlowLayout layout = new FlowLayout();
      layout.setHgap(10);              
      layout.setVgap(10);
      
      panel.setLayout(layout);        
      panel.add(new JButton("OK"));
      panel.add(new JButton("Cancel"));       
      controlPanel.add(panel);
      mainFrame.setVisible(true);  
   }
}

Compile the program using the command prompt. Go to D:/ > SWING and type the following command.

D:\SWING>javac com\tutorialspoint\gui\SwingLayoutDemo.java

If no error occurs, it means the compilation is successful. Run the program using the following command.

D:\SWING>java com.tutorialspoint.gui.SwingLayoutDemo

Verify the following output.

swing_layouts.htm

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