Java元素排列

Question

我有以下代碼。如果我最大化applet的窗口，所有元素將在一行中排序。我想在一行上有一些元素，在另一行上有其他元素等等。我試圖創建面板，但它不起作用。爲了解決這個問題，我應該改變什麼？

import java.applet.Applet; 
import java.awt.*; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 


public class Numbers extends Applet implements ActionListener{ 
private Button b1,b2,b3; 
private Label lb1,lb2,lb3; 
private TextField tf1,tf2,tf3; 
private Panel row1,row2,row3,row4,row5; 
private Panel CreatePanel(LayoutManager layout_type) 
{ 
Panel p=new Panel(); 
p.setLayout(layout_type); 
return p;   
} 
public void init() { 
    setLayout(new FlowLayout(FlowLayout.LEFT,4,2)); 
    row1=CreatePanel(new FlowLayout(FlowLayout.CENTER,4,2)); 
    lb1=new Label("First number: "); 
    tf1=new TextField("",10); 
    row1.add(lb1); 
    row1.add(tf1); 
    add(row1); 
    row2=CreatePanel(new FlowLayout(FlowLayout.CENTER,2,2)); 
    lb2=new Label("Second number: "); 
    row2.add(lb2); 
    tf2=new TextField("",10); 
    row2.add(tf2); 
    add(row2); 
    row3=CreatePanel(new FlowLayout(FlowLayout.CENTER,4,2)); 
    b1=new Button("Multiply "); 
    b1.addActionListener(this); 
    row3.add(b1); 
    b2=new Button("Add"); 
    b2.addActionListener(this); 
    row3.add(b2); 
    b3=new Button("Subtract"); 
    b3.addActionListener(this); 
    row3.add(b3); 
    add(row3); 
    row4=CreatePanel(new FlowLayout(FlowLayout.CENTER,4,2)); 
    row5=CreatePanel(new FlowLayout(FlowLayout.CENTER,5,2)); 
    lb3=new Label("Result:   "); 
    row5.add(lb3); 
    add(row5); 
    } 
    public void actionPerformed(ActionEvent e) 
    { 
    String txt1=tf1.getText(); 
    String txt2=tf2.getText(); 
    int n=Integer.parseInt(txt1); 
    int m=Integer.parseInt(txt2); 
    if(e.getSource()==b1) 
    lb3.setText("Result: "+n*m); 
    if(e.getSource()==b2) 
     lb3.setText("Result: "+(n+m)); 
    if(e.getSource()==b3) 
     lb3.setText("Result: "+(n-m));    
    } 



    } 

Answer 1

您可以GridLayout嘗試爲根面板，並添加所有其它面板在裏面。

瞭解更多關於A Visual Guide to Layout Managers的地方，以及樣例代碼。

示例代碼：

public void init() { 
    Panel rootPanel = CreatePanel(new GridLayout(4, 1)); // 4 rows with 1 column 
    ... 
    rootPanel.add(row1); 
    ... 
    rootPanel.add(row2); 
    ... 
    rootPanel.add(row3); 
    ... 
    rootPanel.add(row5); 

    add(rootPanel); 
} 

注：始終遵循​​