Java AWT | GridLayout 类
GridLayout 类表示在矩形网格中具有指定行数和列数的布局管理器。GridLayout 容器被分成大小相等的矩形，每个矩形中放置一个组件。每个矩形单元格都有相同的大小，因此，它们包含一个填充整个单元格的组件。当用户改变或调整容器的尺寸时，每个矩形的尺寸也相应地改变。
类的构造函数:
- GridLayout(): 它创建一个网格布局，默认每个组件在一行中有一列。
- GridLayout(int rw，int cl): 它创建具有指定行数和列数的网格布局。
- GridLayout(int rw，int cl，int hgap，int vgap): 它创建具有指定行数和列数的网格布局，并具有水平和垂直间隙。
常用方法:
- 添加布局组件(String str，Component cmp): 将具有指定名称的指定组件添加到布局中。
- 设置列数(int cl): 将此布局中的列数设置为指定值。
- 设置 Hgap(int hgap): 将组件之间的水平间隙设置为指定值。
- 设置行数(int rw): 将此布局中的行数设置为指定值。
- 设置 Vgap(int vgap): 将组件之间的垂直间隙设置为指定值。
- layoutContainer(Container pr):使用此布局布局指定的容器。
- toString(): 返回该网格布局值的字符串表示形式。
下面的程序说明了网格布局类:
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Program 1: In below program we are passing the argument in GridLayout. We create 4 JLabel components named “one“, “two“, “three“, “four” and create 2 JButton components named “buttonsave” and “buttonexit” and create 4 Jtextfield components named “tname“, “tcode“, “tdesig“, “tsalary” and all of add them to the JFrame by the method add(). We will set the visibility and size of the frame by using setVisible() and setSize() method. The layout is set by using setLayout() method.
```java // Java program to illustrate the GridLayout import javax.swing.; import java.awt.;
// class GridLayout extends JFrame public class GridLayoutDemo extends JFrame {
GridLayoutDemo() {
// Creating Object P1 of JPanel class JPanel p1 = new JPanel();
// set the layout p1.setLayout(new GridLayout(4, 2));
// Creating Object of "FlowLayout" class FlowLayout layout = new FlowLayout();
// Creating Object P2 of JPanel class JPanel p2 = new JPanel();
// set the layout p2.setLayout(layout);
// Declaration of objects of JLabel class. JLabel one, two, three, four;
// Declaration of objects of JTextField class. JTextField tname, tsalary, tcode, tdesig;
// Declaration of objects of JButton class. JButton buttonSave, buttonExit;
// Initialization of object // "one" of JLabel class. one = new JLabel("NAME");
// Initialization of object // "tname" of JTextField class. tname = new JTextField(20);
// Initialization of object // "two" of JLabel class. two = new JLabel("CODE");
// Initialization of object // "tcode" of JTextField class. tcode = new JTextField(20);
// Initialization of object // "three" of JLabel class. three = new JLabel("DESIGNATION");
// Initialization of object // "tdesig" of JTextField class. tdesig = new JTextField(20);
// Initialization of object // "four" of JLabel class. four = new JLabel("SALARY");
// Initialization of object // "tsalary" of JTextField class. tsalary = new JTextField(20);
// Initialization of object // "buttonsave" of JButton class. buttonSave = new JButton("SAVE");
// Initialization of object // "buttonexit" of JButton class. buttonExit = new JButton("EXIT");
// Adding Jlabel "one" on JFrame. p1.add(one);
// Adding JTextField "tname" on JFrame. p1.add(tname);
// Adding Jlabel "two" on JFrame. p1.add(two);
// Adding JTextField "tcode" on JFrame. p1.add(tcode);
// Adding Jlabel "three" on JFrame. p1.add(three);
// Adding JTextField "tdesig" on JFrame. p1.add(tdesig);
// Adding Jlabel "four" on JFrame. p1.add(four);
// Adding JTextField "tsalary" on JFrame. p1.add(tsalary);
// Adding JButton "buttonsave" on JFrame. p2.add(buttonSave);
// Adding JButton "buttonexit" on JFrame. p2.add(buttonExit);
// add the p1 object which // refer to the Jpanel add(p1, "North");
// add the p2 object which // refer to the Jpanel add(p2, "South");
// Function to set visible // status of JFrame. setVisible(true);
// this Keyword refers to current // object. Function to set size of JFrame. this.setSize(400, 180); }
// Main Method public static void main(String args[]) {
// calling the constructor new GridLayoutDemo(); } } ```
输出:
https://media.geeksforgeeks.org/wp-content/uploads/Untitled-14.mp4 * Program 2: In below program we are passing the argument in GridLayout. We create 5 JButton components named “btn1“, “btn2“, “btn3“, “btn4“, “btn5” and then add them to the JFrame by the method add(). We will set the visibility and size of the frame by using setvisible() and setsize() method. The layout is set by using setLayout() method.
```java // Java program to illustrate the GridLayout import java.awt.; import javax.swing.;
// create a class griddemo public class Griddemo {
// Main Method public static void main(String[] args) {
// Creating Object of JFrame class // with new name frame JFrame frame = new JFrame("GridLayout Demo");
// Initialization of object // "btn1" of JButton class. JButton btn1 = new JButton("Button 1");
// Initialization of object // "btn2" of JButton class. JButton btn2 = new JButton("Button 2");
// Initialization of object // "btn3" of JButton class. JButton btn3 = new JButton("Button 3");
// Initialization of object // "btn4" of JButton class. JButton btn4 = new JButton("Button 4");
// Initialization of object // "btn5" of JButton class. JButton btn5 = new JButton("Button 5");
// Creating Object Panel of JPanel class // create grid layout with 3 rows, // 2 columns with horizontal and // vertical gap set to 10 JPanel panel = new JPanel(new GridLayout(3, 2, 10, 10));
// Adding JButton "btn1" on JPanel. panel.add(btn1);
// Adding JButton "btn2" on JPanel. panel.add(btn2);
// Adding JButton "btn3" on JPanel. panel.add(btn3);
// Adding JButton "btn4" on JPanel. panel.add(btn4);
// Adding JButton "btn5" on JPanel. panel.add(btn5);
// Function to close the operation of JFrame. frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
// Function to set size of JFrame. frame.setSize(300, 150);
// Function to get the content of JFrame. frame.getContentPane().add(panel);
// Function to set visible status of JFrame. frame.setVisible(true); } } ```
输出:
https://media.geeksforgeeks.org/wp-content/uploads/Untitled-13Trim-2.mp4
注意:上述程序可能无法在在线 IDE 中运行。请使用离线编译器。
参考:https://docs . Oracle . com/javase/7/docs/API/Java/awt/gridlayout . html
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