AS3初探

开发工具： FLEX BUILDER3 PRO

 

语言： AS 3.0

 

操作系统： Windows XP SP2

 

1.       在 flex3 里新建一个 AS 工程取名为 login2

2.       导入所需要的包（如果无法使用fl包，请参照我的前一篇文章：flex3 里如何导入FLASH CS3的包）

   import fl.controls.Button;

    import fl.controls.Label;

    import fl.controls.TextInput;

   

    import flash.display.Sprite;

    import flash.events.MouseEvent;

3.       定义变量（将来在舞台上出现的对象）

       // 用户名标签和输入框

       private var username_label:Label;

       private var username_txt:TextInput;

      

       // 密码标签和输入框

       private var pwd_label:Label;

       private var pwd_txt:TextInput;

      

       // 登录按钮

       private var login_btn:Button;

      

       // 提示消息

       private var showmsg_label:Label;

4.    定义函数让以上的对象并添加到在舞台上

   // 定义用户名标签函数

       private function setusernamelabel(): void

       {

           username_label = new Label();

           username_label.text = "UserName" ;

           username_label.move(10,10);

           this .addChild(username_label);

       }

      

       private function setusernametxt(): void

       {

           username_txt = new TextInput();

           username_txt.move(90,10);

           this .addChild(username_txt);

       }

      

       // 定义密码标签函数

       private function setpwdlabel(): void

       {

           pwd_label = new Label();

           pwd_label.text = "PassWord" ;

           pwd_label.move(10,40);

           this .addChild(pwd_label);

       }

      

       private function setpwdtxt(): void

       {

           pwd_txt = new TextInput();

           pwd_txt.displayAsPassword = true ;

           pwd_txt.move(90,40);

           this .addChild(pwd_txt);

       }

      

       // 初始化状态信息标签

       private function setshowmsg(): void

       {

           showmsg_label = new Label();

           showmsg_label.move(90,100);

           showmsg_label.text = "" ;

           this .addChild(showmsg_label);

       }

      

       // 定义 login 按钮函数

       private function setButton(): void

       {

           login_btn = new Button();

           login_btn.label = "Login" ;

           login_btn.move(90,70);

           login_btn.addEventListener(MouseEvent.CLICK,login_click);

           this .addChild(login_btn);

       }

5.    定义事件函数，这里定义的是鼠标事件

    private function login_click(e:MouseEvent): void

       {

          

           if (username_txt.text != "admin" || pwd_txt.text != "admin" )

           {

              showmsg_label.text = "UserName or Password is Error!" ;

              disableText();

           }

           else

           {

              showmsg_label.text = "Login Success!" ;

           }

          

       }

6.    在构造函数里初始化这些函数，否则舞台上是不会显示任何东西的，注意在这个函数过程中任何对象的引用都要先初始化，否则会提示无法引用空对象！

 

    private function setshowmsg(): void

       {

           showmsg_label = new Label();

           showmsg_label.move(90,100);

           showmsg_label.text = "" ;

           this .addChild(showmsg_label);

       }

7.    测试。

8.    完整代码：

package {

 

    import fl.controls.Button;

    import fl.controls.Label;

    import fl.controls.TextInput;

   

    import flash.display.Sprite;

    import flash.events.MouseEvent;

 

    public class login2 extends Sprite

    {

       // 用户名标签和输入框

       private var username_label:Label;

       private var username_txt:TextInput;

      

       // 密码标签和输入框

       private var pwd_label:Label;

       private var pwd_txt:TextInput;

      

       // 登录按钮

       private var login_btn:Button;

      

       // 提示消息

       private var showmsg_label:Label;

      

       public function login2()

       {

           setusernamelabel();

           setusernametxt();

           setpwdlabel();

           setpwdtxt();

           setButton();

           setshowmsg();

          

          

       }

       // 定义用户名标签函数

       private function setusernamelabel(): void

       {

           username_label = new Label();

           username_label.text = "UserName" ;

           username_label.move(10,10);

           this .addChild(username_label);

       }

      

       private function setusernametxt(): void

       {

           username_txt = new TextInput();

           username_txt.move(90,10);

           this .addChild(username_txt);

       }

      

       // 定义密码标签函数

       private function setpwdlabel(): void

       {

           pwd_label = new Label();

           pwd_label.text = "PassWord" ;

           pwd_label.move(10,40);

           this .addChild(pwd_label);

       }

      

       private function setpwdtxt(): void

       {

           pwd_txt = new TextInput();

           pwd_txt.displayAsPassword = true ;

           pwd_txt.move(90,40);

           this .addChild(pwd_txt);

       }

      

       // 初始化状态信息标签

       private function setshowmsg(): void

       {

           showmsg_label = new Label();

           showmsg_label.move(90,100);

           showmsg_label.text = "" ;

           this .addChild(showmsg_label);

       }

      

       // 定义 login 按钮函数

       private function setButton(): void

       {

           login_btn = new Button();

           login_btn.label = "Login" ;

           login_btn.move(90,70);

           login_btn.addEventListener(MouseEvent.CLICK,login_click);

           this .addChild(login_btn);

       }

       private function login_click(e:MouseEvent): void

       {

          

           if (username_txt.text != "admin" || pwd_txt.text != "admin" )

           {

              showmsg_label.text = "UserName or Password is Error!" ;

              disableText();

           }

           else

           {

              showmsg_label.text = "Login Success!" ;

           }

          

       }

       private function disableText(): void

       {

           username_txt.enabled = false ;

           pwd_txt.enabled = false ;

       }

      

    }

}