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 ;
}
}
}
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