Java程序設計實訓教程課件7圖形界面1

本章內容圖形用戶界面開發(fā)概述Java事件模型常用組件與事件處理

圖形用戶界面開發(fā)概述人機交互的窗口，由一組圖形界面成分和界面元素組成。主要工作：

創(chuàng)建界面，設置并布局，形成物理外觀；定義事件和響應，實現(xiàn)交互功能。組成：容器、控制組件和用戶自定義成分

容器：組織界面成分和元素。控制組件：圖形用戶界面組成單位。用戶自定義部分：根據(jù)需要可自定義圖形、標志圖案等。AWT組件AWT——abstractwindowtoolkit(抽象窗口工具包)建立JFC的主要基礎；Swing組件：建立在AWT之上，新的、功能更強大的圖形組件包。事件類字體類GraphicsComponent顏色類布局管理類java.lang.ObjectCheckboxContainerButton…WindowPanelAppletDialogFrameList圖象類菜單類JavaApplet一個JavaApplet程序中必須有一個類是Applet的子類publicclassExample8_1extendsAppletApplet類是包java.applet中的一個類，也是java.awt中Container的子類importjava.applet.*;publicvoidinit(){….}publicvoidstart(){……}publicvoidstop(){……}publicvoiddestroy(){….}publicvoidpaint(Graphicsg){……}publicvoidrepaint(Graphicsg){……}初始化init（）啟動start（）中止stop（）銷毀destroy（）瀏覽器下載并實例化Applet轉入后臺重新激活Applet退出瀏覽器Applet生命周期：

常用組件

Component類importjava.awt.*;importjava.awt.event.*;importjava.applet.*;publicclassMyWindow1extendsApplet

implementsActionListener{

privateButtonm_btn=newButton(“test”);publicvoidinit(){add(m_btn);

m_btn.addActionListener(this);}//init()

publicvoidactionPerformed(ActionEvente){System.out.println(“Hello”);}//實現(xiàn)接口

}//MyWindowJava事件模型事件源注冊：btn.addActionListener(監(jiān)聽者對象）監(jiān)聽者類實現(xiàn)接口：publicvoidactionPerformed(ActionEvente)ActionEvent類型注冊觸發(fā)事件調用并傳遞參數(shù)ActionEvent類常用方法publicObjectgetSource(){…}

獲取發(fā)生ActionEvent事件的事件源對象例：publicvoidactionPerformed(ActionEvente){if(e.getSource()==text1)label1.setText(“It’stext1!”);elseif(e.getSource()==text2)label1.setText(“It’stext2!”);…….}publicStringgetActionCommand(){…}發(fā)生事件時，獲取文本框中的文本字符串例：publicvoidactionPerformed(ActionEvente){Strings=e.getActionCommand();label1.setText(s);}事件模型實現(xiàn)方法：方法1：定義類時實現(xiàn)監(jiān)聽接口publicclassMyWindow1extendsApplet

implementsActionListener{

privateButtonm_btn=newButton(“test”);publicvoidinit(){

add(m_btn);m_btn.addActionListener(this);}

publicvoidactionPerformed(ActionEvente){……}}方法2：在另一個類中實現(xiàn)監(jiān)聽接口

publicclassLess6extendsApplet{privateButtonm_btn=newButton(“test”);publicvoidinit(){

add(m_btn);m_btn.addActionListener(newbtnListener());}//init()}//Less6classbtnListenerimplementsActionListener{publicvoidactionPerformed(ActionEvente){

m_btn.setLabel(“事件被觸發(fā)”);}//實現(xiàn)事件接口

}//btnListener

方法3：創(chuàng)建匿名內部類importjava.applet.*;importjava.awt.*;Importjava.awt.event.*;

publicclasstestextendsApplet

{

privateButtonm_btn=newButton(“test”);publicvoidinit(){add(m_btn);m_btn.addActionListener(newActionListener(){publicvoidactionPerformed(ActionEvente){

m_btn.setLabel(“事件被觸發(fā)”);

}//actionPerformed

});}//init()}//testEventObjectActionEventItemEventAdjustmentEventComponentEventTextEventAWTEventMouseEventKeyEventContainerEventPaintEventFocusEventInputEventWindowEvent事件類體系結構圖：事件類監(jiān)聽器接口增加監(jiān)聽器方法刪除監(jiān)聽器方法ActionEventActionListeneraddActionListener()removeActionListener()AdjustmentEventAdjustmentListeneraddAdjustmentListener()removeAdjustmentListener()ComponentEventComponentListeneraddComponentListener()removeComponentListener()ContainerEventContainerListeneraddContainerListener()removeContainerListener()FocusEventFocusListeneraddFocusListener()removeFocusListener()KeyEventKeyListeneraddKeyListener()removeKeyListener()MouseEventMouseListeneraddMouseListener()removeMouseListener()MouseMotionListeneraddMouseMotionListener()removeMouseMotionListener()WindowEventWindowListeneraddWindowListener()removeWindowListener()ItemEventItemListeneraddItemListener()removeItemListener()TextEventTextListeneraddTextListener()removeTextListener()事件與監(jiān)聽器對照表監(jiān)聽器接口接口中的函數(shù)ActionListeneractionPerformedAdjustmentListeneradjustmentValueChangedComponentListenercomponentHidden,componentShown,componentMoved,componentResizedContainerListenercomponentAdded,componentRemovedFocusListenerfocusGained,focusLostKeyListenerkeyPressed,keyReleased,keyTypedMouseListenermouseClicked,mouseEntered,mouseExited,mousePressed,mouseReleasedMouseMotionListenermouseDragged,mouseMovedWindowListenerwindowOpened,windowClosing,windowClosed,windowActivated,windowDeactivated,windowIconified,windowDeiconifiedItemListeneritemStateChangedTextListenertextValueChanged標簽（Label）創(chuàng)建標簽

Label

prompt

=

newLabel(“你好”);常用方法

getText()setText(Strings)

if(prompt.getText()==“你好”）

prompt.setText(“再見”);產生事件

標簽不能接收用戶輸入，所以不能引發(fā)事件。按鈕（Button）創(chuàng)建按鈕

Button

btn=

newButton(“操作”);常用方法

getLabel()setLabel(Strings)

Strings=btn.getLabel();btn.setLabel(“你好”);產生事件

單擊按鈕引發(fā)動作事件ActionEvent

對應的監(jiān)聽接口是ActionListener

文本框（TextField）P131創(chuàng)建文本框

TextFieldtxt=newTextField();TextFieldtxt=newTextField(“hello”);TextFieldtxt=newTextField(10);TextFieldtxt=newTextField(“hel