我在一個項目中使用eclipse中的Window Builder。我正在嘗試添加啓動畫面。我得到的錯誤類型進度條無法解析

Question

我在GUI項目中使用eclipse中的Window Builder。我想添加一個啓動畫面用進度條轉到主頁加載達到100％之後。我得到的錯誤類型進度欄不能在運行（）來解決

import java.awt.EventQueue;  
import javax.swing.JFrame; 
import javax.swing.JPanel; 
import javax.swing.border.EmptyBorder; 
import javax.swing.JLabel; 
import javax.swing.JOptionPane; 

import java.awt.Font; 
import java.awt.Color; 
import javax.swing.UIManager; 
import javax.swing.JProgressBar; 
import javax.swing.ProgressMonitor; 

import java.awt.SystemColor; 
import java.sql.Connection; 

import javax.swing.border.LineBorder; 
import javax.swing.plaf.ProgressBarUI; 

@SuppressWarnings("serial") 
public class Loading extends JFrame implements Runnable{ 

    Connection conn; 
    int s=0; 
    Thread th; 



    private JPanel contentPane; 



    /** 
    * Create the frame. 
    */ 
    public Loading() { 

     super("Loading"); 
     th = new Thread((Runnable) this); 

     setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     setBounds(100, 100, 540, 363); 
     contentPane = new JPanel(); 
     contentPane.setBorder(new LineBorder(new Color(250, 128, 114), 2)); 
     setContentPane(contentPane); 
     contentPane.setLayout(null); 

     JLabel lblSmartLibrary = new JLabel("# Library"); 
     lblSmartLibrary.setForeground(UIManager.getColor("RadioButtonMenuItem.selectionBackground")); 
     lblSmartLibrary.setFont(new Font("Times New Roman", Font.PLAIN, 20)); 
     lblSmartLibrary.setBounds(225, 43, 144, 24); 
     contentPane.add(lblSmartLibrary); 

     JProgressBar progressBar = new JProgressBar(); 
     progressBar.setValue(0); 
     progressBar.setStringPainted(true); 
     progressBar.setForeground(new Color(135, 206, 250)); 
     progressBar.setBackground(SystemColor.window); 
     progressBar.setBounds(190, 151, 150, 32); 
     contentPane.add(progressBar); 

     JLabel lblPleaseWait = new JLabel("Please wait..."); 
     lblPleaseWait.setBounds(225, 182, 88, 16); 
     contentPane.add(lblPleaseWait); 

    } 

    public void setupLoading(){ 
     setVisible(false); 
     th.start(); 
    } 

    public void run(){ 
     try{ 
      for (int i=1; i<= 200; i++){ 
       s = s + 1; 
      //The error is Here.Type progressBar cannot be resolved     
       int m = progressBar.getMaximum(); 
       int v= progressBar.getValue(); 
       if(v<m){ 
        progressBar.setValue(progressBar.getValue()+1); 

       }else{ 
        i=201; 
        setVisible(false); 
        Home ob = new Home(); 
        ob.setVisible(true); 
       }Thread.sleep(50); 
      } 
     }catch (Exception e){ 
      JOptionPane.showMessageDialog(null, e); 
     } 

    } 

    /** 
    * Launch the application. 
    */ 
    public static void main(String[] args) { 
     EventQueue.invokeLater(new Runnable() { 
      public void run() { 
       try { 
        Loading frame = new Loading(); 
        frame.setVisible(true); 
       } catch (Exception e) { 
        e.printStackTrace(); 
       } 
      } 
     }); 
    } 
} 

Answer 1

沒有變或名爲progressBar [在可見範圍內]的字段。所以對語法的下一個可能的解釋是它是一個名爲progressBar的類上的一些靜態方法的調用。如果該類不存在，那就是你得到的錯誤。

Answer 2

已將我的代碼更改爲以下版本，並能正常工作。

import java.awt.BorderLayout; 
import java.awt.EventQueue; 

import javax.swing.JFrame; 
import javax.swing.JPanel; 
import javax.swing.border.EmptyBorder; 
import javax.swing.UIManager; 
import javax.swing.border.LineBorder; 
import java.awt.Color; 
import javax.swing.JLabel; 
import javax.swing.JOptionPane; 

import java.awt.Font; 
import java.sql.Connection; 

import javax.swing.JProgressBar; 
import javax.swing.SwingUtilities; 
import javax.swing.SwingConstants; 
import java.awt.Window.Type; 


public class Loading extends JFrame{ 

    Connection conn; 
    private Task task; 
    private JProgressBar progressBar; 


    private JPanel contentPane; 


    /** 
    * Launch the application. 
    */ 
    public static void main(String[] args) { 
     EventQueue.invokeLater(new Runnable() { 
      public void run() { 
       try { 
        Loading frame = new Loading(); 
        frame.setVisible(true); 
       } catch (Exception e) { 
        e.printStackTrace(); 
       } 
      } 
     }); 
    } 

    /** 
    * Create the frame. 
    */ 
    public Loading() { 
     setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     setBounds(100, 100, 450, 300); 
     contentPane = new JPanel(); 
     contentPane.setBorder(new EmptyBorder(5, 5, 5, 5)); 
     setContentPane(contentPane); 
     contentPane.setLayout(null); 

     JPanel panel = new JPanel(); 
     panel.setBorder(new LineBorder(new Color(153, 204, 255), 3)); 
     panel.setForeground(UIManager.getColor("ProgressBar.background")); 
     panel.setBounds(30, 26, 391, 220); 
     contentPane.add(panel); 
     panel.setLayout(null); 

     JLabel lblLibrary = new JLabel("Loading"); 
     lblLibrary.setHorizontalAlignment(SwingConstants.CENTER); 
     lblLibrary.setFont(new Font("Lucida Grande", Font.PLAIN, 20)); 
     lblLibrary.setBounds(146, 23, 107, 45); 
     panel.add(lblLibrary); 

     progressBar = new JProgressBar(0,100); 
     lblLibrary.setLabelFor(progressBar); 
     progressBar.setStringPainted(true); 
     progressBar.setValue(0); 
     progressBar.setForeground(new Color(0, 51, 255)); 
     progressBar.setBounds(120, 80, 146, 20); 
     panel.add(progressBar); 

     JLabel lblPleaseWait = new JLabel("Please wait..."); 
     lblPleaseWait.setBounds(146, 109, 81, 16); 
     panel.add(lblPleaseWait); 
    } 

    public void setUpLoading(){ 
     setVisible(false); 
     task = new Task(); 
     task.start(); 
     ; 
    } 


    private class Task extends Thread {  
     public Task(){ 
      } 
      public void run(){ 
      for(int i =0; i<= 100; i+=1){ 
       final int progress = i; 

       SwingUtilities.invokeLater(new Runnable() { 
        public void run() { 
         progressBar.setValue(progress); 
        } 
       }); 
        if(progress==100){ 
         setVisible(false); 
         Home ob = new Home(); 
         ob.setVisible(true); 
        } 
       try { 
        Thread.sleep(100); 
       } catch (InterruptedException e) {} 
      } 
      } 
     } 
    }