AWT GridBagLayout

介绍

GridBagLayout 类组件排列在一个水平和垂直的方式。

类的声明

以下是声明的java.awt.GridBagLayout类：

public class GridBagLayout
   extends Object
      implements LayoutManager2, Serializable

字段域

下面是java.awt.BorderLayout类的字段：

double[] columnWeights -- 此字段存放列权重的重写。
int[] columnWidths -- 此字段中拥有覆盖列的最小宽度。
protected Hashtable comptable -- 这个哈希表维护组件和它的网格包约束之间的关联。
protected GridBagConstraints defaultConstraints -- 此字段保存网格包约束实例包含默认值，因此如果某个组件没有与它相关联的网格包约束，那么该组件将被分配副本defaultConstraints
protected java.awt.GridBagLayoutInfo layoutInfo -- 此字段持有网格包布局信息。
protected static int MAXGRIDSIZE -- 最大数量的的网格位置（水平和垂直），可以铺设是由网格包布局。
protected static int MINSIZE -- 可安排最小的网格由网格包布局。
protected static int PREFERREDSIZE -- 首选的网格大小，可以布局网格袋布局。
int[] rowHeights -- 此字段持有覆盖到该行的最低高度。
double[] rowWeights -- 此字段持有行权的重写。

类的构造函数

S.N.	构造函数与说明
1	GridBagLayout() Creates a grid bag layout manager.

类方法

S.N.	Method & Description
1	void addLayoutComponent(Component comp, Object constraints) Adds the specified component to the layout, using the specified constraints object.
2	void addLayoutComponent(String name, Component comp) Adds the specified component with the specified name to the layout.
3	protected void adjustForGravity(GridBagConstraints constraints, Rectangle r) Adjusts the x, y, width, and height fields to the correct values depending on the constraint geometry and pads.
4	protected void AdjustForGravity(GridBagConstraints constraints, Rectangle r) This method is obsolete and supplied for backwards compatability only; new code should call adjustForGravity instead.
5	protected void arrangeGrid(Container parent) Lays out the grid.
6	protected void ArrangeGrid(Container parent) This method is obsolete and supplied for backwards compatability only; new code should call arrangeGrid instead.
7	GridBagConstraints getConstraints(Component comp) Gets the constraints for the specified component.
8	float getLayoutAlignmentX(Container parent) Returns the alignment along the x axis.
9	float getLayoutAlignmentY(Container parent) Returns the alignment along the y axis.
10	int[][] getLayoutDimensions() Determines column widths and row heights for the layout grid.
11	protected java.awt.GridBagLayoutInfo getLayoutInfo(Container parent, int sizeflag) Fills in an instance of GridBagLayoutInfo for the current set of managed children.
12	protected java.awt.GridBagLayoutInfo GetLayoutInfo(Container parent, int sizeflag) This method is obsolete and supplied for backwards compatability only; new code should call getLayoutInfo instead.
13	Point getLayoutOrigin() Determines the origin of the layout area, in the graphics coordinate space of the target container.
14	double[][] getLayoutWeights() Determines the weights of the layout grid's columns and rows.
15	protected Dimension getMinSize(Container parent, java.awt.GridBagLayoutInfo info) Figures out the minimum size of the master based on the information from getLayoutInfo().
16	protected Dimension GetMinSize(Container parent, java.awt.GridBagLayoutInfo info) This method is obsolete and supplied for backwards compatability only; new code should call getMinSize instead.
17	void invalidateLayout(Container target) Invalidates the layout, indicating that if the layout manager has cached information it should be discarded.
18	void layoutContainer(Container parent) Lays out the specified container using this grid bag layout.
19	Point location(int x, int y) Determines which cell in the layout grid contains the point specified by (x, y).
20	protected GridBagConstraints lookupConstraints(Component comp) Retrieves the constraints for the specified component.
21	Dimension maximumLayoutSize(Container target) Returns the maximum dimensions for this layout given the components in the specified target container.
22	Dimension minimumLayoutSize(Container parent) Determines the minimum size of the parent container using this grid bag layout.
23	Dimension preferredLayoutSize(Container parent) Determines the preferred size of the parent container using this grid bag layout.
24	void removeLayoutComponent(Component comp) Removes the specified component from this layout.
25	void setConstraints(Component comp, GridBagConstraints constraints) Sets the constraints for the specified component in this layout.
26	String toString() Returns a string representation of this grid bag layout's values.

继承的方法

这个类继承的方法从以下类：

java.lang.Object

GridBagLayout 实例

选择使用任何编辑器创建以下java程序 D:/ > AWT > com > yiibai > gui >

AwtLayoutDemo

package com.yiibai.gui;

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

public class AwtLayoutDemo {
   private Frame mainFrame;
   private Label headerLabel;
   private Label statusLabel;
   private Panel controlPanel;
   private Label msglabel;

   public AwtLayoutDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      AwtLayoutDemo  awtLayoutDemo = new AwtLayoutDemo();  
      awtLayoutDemo.showGridBagLayoutDemo();       
   }
      
   private void prepareGUI(){
      mainFrame = new Frame("Java AWT Examples");
      mainFrame.setSize(400,400);
      mainFrame.setLayout(new GridLayout(3, 1));
      mainFrame.addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent windowEvent){
            System.exit(0);
         }        
      });    
      headerLabel = new Label();
      headerLabel.setAlignment(Label.CENTER);
      statusLabel = new Label();        
      statusLabel.setAlignment(Label.CENTER);
      statusLabel.setSize(350,100);

      msglabel = new Label();
      msglabel.setAlignment(Label.CENTER);
      msglabel.setText("Welcome to TutorialsPoint AWT Tutorial.");

      controlPanel = new Panel();
      controlPanel.setLayout(new FlowLayout());

      mainFrame.add(headerLabel);
      mainFrame.add(controlPanel);
      mainFrame.add(statusLabel);
      mainFrame.setVisible(true);  
   }

   private void showGridBagLayoutDemo(){
      headerLabel.setText("Layout in action: GridBagLayout");      

      Panel panel = new Panel();
      panel.setBackground(Color.darkGray);
      panel.setSize(300,300);
      GridBagLayout layout = new GridBagLayout();

      panel.setLayout(layout);        
      GridBagConstraints gbc = new GridBagConstraints();

      gbc.fill = GridBagConstraints.HORIZONTAL;
      gbc.gridx = 0;
      gbc.gridy = 0;
      panel.add(new Button("Button 1"),gbc);

      gbc.gridx = 1;
      gbc.gridy = 0;
      panel.add(new Button("Button 2"),gbc); 

      gbc.fill = GridBagConstraints.HORIZONTAL;
      gbc.ipady = 20;   
      gbc.gridx = 0;
      gbc.gridy = 1;
      panel.add(new Button("Button 3"),gbc); 

      gbc.gridx = 1;
      gbc.gridy = 1;       
      panel.add(new Button("Button 4"),gbc);  

      gbc.gridx = 0;
      gbc.gridy = 2;      
      gbc.fill = GridBagConstraints.HORIZONTAL;
      gbc.gridwidth = 2;
      panel.add(new Button("Button 5"),gbc);  

      controlPanel.add(panel);

      mainFrame.setVisible(true);  
   }
}

编译程序，使用命令提示符。进入到D:/> AWT，然后键入以下命令。

D:AWT>javac comyiibaiguiAwtlayoutDemo.java

如果没有错误出现，这意味着编译成功。使用下面的命令来运行程序。

D:AWT>java com.yiibai.gui.AwtlayoutDemo

验证下面的输出