说明:示范如何利用AlertView来制作系统登入的介面
    
    
    
      
         
      
      
      
      
      程式碼:
      
      CustomAlertViewViewController.h 
    
  
    
      
        
    
  
    #import <UIKit/UIKit.h>
//記得加入UIAlertViewDelete
@interface CustomAlertViewViewController : UIViewController<UIAlertViewDelegate> {
    UIAlertView *myAlertView;
}
@property (nonatomic,retain) UIAlertView *myAlertView;
-(IBAction) buttonPressed:(id)sender;
@end
CustomAlertViewViewController.m 
-(IBAction) buttonPressed:(id)sender{
    myAlertView=[[UIAlertView alloc] initWithTitle:@"系統登入" message:nil delegate:self cancelButtonTitle:@"取消" otherButtonTitles:@"登入",nil];
    [myAlertView show];
    [myAlertView release];
    
}
- (void)willPresentAlertView:(UIAlertView *)alertView
{
        CGRect frame = alertView.frame;
        if( alertView==myAlertView )
        {
                frame.origin.y -= 120;
                frame.size.height += 80;
                alertView.frame = frame;
                for( UIView * view in alertView.subviews )
                {
            //列舉alertView中所有的物件
                        if( ![view isKindOfClass:[UILabel class]] )
                        {
            //若不UILable則另行處理
                if (view.tag==1)
                {
                //處理第一個按鈕,也就是 CancelButton
                           CGRect btnFrame1 =CGRectMake(30, frame.size.height-65, 105, 40);
                                view.frame = btnFrame1;
               
                } else if  (view.tag==2){
                //處理第二個按鈕,也就是otherButton    
                    CGRect btnFrame2 =CGRectMake(142, frame.size.height-65, 105, 40);
                    view.frame = btnFrame2;               
                }
                        }
                }
                
        //加入自訂的label及UITextFiled
        UILabel *lblaccountName=[[UILabel alloc] initWithFrame:CGRectMake( 30, 50,60, 30 )];;
        lblaccountName.text=@"帳號:";
        lblaccountName.backgroundColor=[UIColor clearColor];
        lblaccountName.textColor=[UIColor whiteColor];
        
        UITextField *accoutName = [[UITextField alloc] initWithFrame: CGRectMake( 85, 50,160, 30 )];   
        accoutName.placeholder = @"帳號名稱";
        accoutName.borderStyle=UITextBorderStyleRoundedRect;
        
        
        UILabel *lblaccountPassword=[[UILabel alloc] initWithFrame:CGRectMake( 30, 85,60, 30 )];;
        lblaccountPassword.text=@"密碼:";
        lblaccountPassword.backgroundColor=[UIColor clearColor];
        lblaccountPassword.textColor=[UIColor whiteColor];
        
        UITextField *accoutPassword = [[UITextField alloc] initWithFrame: CGRectMake( 85, 85,160, 30 )];   
        accoutPassword.placeholder = @"登入密碼";
        accoutPassword.borderStyle=UITextBorderStyleRoundedRect;
        //輸入的資料以星號顯示(密碼資料)
        accoutPassword.secureTextEntry=YES;
        
             [alertView addSubview:lblaccountName];
                [alertView addSubview:accoutName];         
        [alertView addSubview:lblaccountPassword];
                [alertView addSubview:accoutPassword];
        }
}
- (void)dealloc {
    [myAlertView release];
    [super dealloc];
}
  
  


 
					 
					