AWT Scrollbar类

介绍

滚动条控制滚动条组件以让用户选择一个范围内的值。

类的声明

以下是的声明类java.awt.Scrollbar：

public class Scrollbar
   extends Component
      implements Adjustable, Accessible

字段域

以下java.awt.image类的字段：

static int HORIZONTAL -- 一个常量，表示一个水平滚动条。
static int VERTICAL -- 一个常量，表示一个垂直滚动条。

类的构造函数

S.N.	构造函数&说明
1	Scrollbar() Constructs a new vertical scroll bar.
2	Scrollbar(int orientation) Constructs a new scroll bar with the specified orientation.
3	Scrollbar(int orientation, int value, int visible, int minimum, int maximum) Constructs a new scroll bar with the specified orientation, initial value, visible amount, and minimum and maximum values.

类方法

AccessibleContext getAccessibleContext（）
获取的AccessibleContext和这个滚动条。 AdjustmentListener[] getAdjustmentListeners()
返回一个数组，在这个滚动条调整监听器注册。 <T extends EventListener>T[] getListeners(Class<T> listenerType)
返回一个数组，目前注册作为FooListeners在这滚动的所有对象。

S.N.	方法& 描述
1	void addAdjustmentListener(AdjustmentListener l) Adds the specified adjustment listener to receive instances of AdjustmentEvent from this scroll bar.
2	void addNotify() Creates the Scrollbar's peer.
3	int getBlockIncrement() Gets the block increment of this scroll bar.
4	int getLineIncrement() Deprecated. As of JDK version 1.1, replaced by getUnitIncrement().
5	int getMaximum() Gets the maximum value of this scroll bar.
6	int getMinimum() Gets the minimum value of this scroll bar.
7	int getOrientation() Returns the orientation of this scroll bar.
8	int getPageIncrement() Deprecated. As of JDK version 1.1, replaced by getBlockIncrement().
9	int getUnitIncrement() Gets the unit increment for this scrollbar.
10	int getValue() Gets the current value of this scroll bar.
11	boolean getValueIsAdjusting() Returns true if the value is in the process of changing as a result of actions being taken by the user.
12	int getVisible() Deprecated. As of JDK version 1.1, replaced by getVisibleAmount().
13	int getVisibleAmount() Gets the visible amount of this scroll bar.
14	protected String paramString() Returns a string representing the state of this Scrollbar.
15	protected void processAdjustmentEvent(AdjustmentEvent e) Processes adjustment events occurring on this scrollbar by dispatching them to any registered AdjustmentListener objects.
16	protected
1	void processEvent(AWTEvent e) Processes events on this scroll bar.
17	void removeAdjustmentListener(AdjustmentListener l) Removes the specified adjustment listener so that it no longer receives instances of AdjustmentEvent from this scroll bar.
18	void setBlockIncrement(int v) Sets the block increment for this scroll bar.
19	void setLineIncrement(int v) Deprecated. As of JDK version 1.1, replaced by setUnitIncrement(int).
20	void setMaximum(int newMaximum) Sets the maximum value of this scroll bar.
21	void setMinimum(int newMinimum) Sets the minimum value of this scroll bar.
22	void setOrientation(int orientation) Sets the orientation for this scroll bar.
23	void setPageIncrement(int v) Deprecated. As of JDK version 1.1, replaced by setBlockIncrement().
24	void setUnitIncrement(int v) Sets the unit increment for this scroll bar.
25	void setValue(int newValue) Sets the value of this scroll bar to the specified value.
26	void setValueIsAdjusting(boolean b) Sets the valueIsAdjusting property.
27	void setValues(int value, int visible, int minimum, int maximum) Sets the values of four properties for this scroll bar: value, visibleAmount, minimum, and maximum.
28	void setVisibleAmount(int newAmount) Sets the visible amount of this scroll bar.

继承的方法

这个类继承的方法从以下类：

java.awt.Component
java.lang.Object

选择示例

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

AwtControlDemo

package com.yiibai.gui;

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

public class AwtControlDemo {

   private Frame mainFrame;
   private Label headerLabel;
   private Label statusLabel;
   private Panel controlPanel;

   public AwtControlDemo(){
      prepareGUI();
   }

   public static void main(String[] args){
      AwtControlDemo  awtControlDemo = new AwtControlDemo();
      awtControlDemo.showScrollbarDemo();
   }

   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);

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

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

   private void showScrollbarDemo(){                                       
      headerLabel.setText("Control in action: Scrollbar"); 

      final Scrollbar horizontalScroller = new Scrollbar(Scrollbar.HORIZONTAL);
      final Scrollbar verticalScroller = new Scrollbar();
      verticalScroller.setOrientation(Scrollbar.VERTICAL);
      horizontalScroller.setMaximum (100);
      horizontalScroller.setMinimum (1);
      verticalScroller.setMaximum (100);
      verticalScroller.setMinimum (1);

      horizontalScroller.addAdjustmentListener(new AdjustmentListener() {

         @Override
         public void adjustmentValueChanged(AdjustmentEvent e) {
            statusLabel.setText("Horozontal: "
               +horizontalScroller.getValue() 
               +" ,Vertical: "
               + verticalScroller.getValue());
            }
         });

      verticalScroller.addAdjustmentListener(new AdjustmentListener() {

            @Override
            public void adjustmentValueChanged(AdjustmentEvent e) {
               statusLabel.setText("Horozontal: "
               +horizontalScroller.getValue() 
               +" ,Vertical: "+ verticalScroller.getValue());
            }
         });

      controlPanel.add(horizontalScroller);
      controlPanel.add(verticalScroller);

      mainFrame.setVisible(true);  
   }
}

编译程序，使用命令提示符。到 D:/ > AWT 然后键入以下命令。

D:AWT>javac comyiibaiguiAwtControlDemo.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.AwtControlDemo

验证下面的输出