#import <UIKit/UIKit.h>@interface PasswordInputWindow : UIWindow+(PasswordInputWindow *)shareInstance;-(void)show;@end

#import "PasswordInputWindow.h"@implementation PasswordInputWindow{    UITextField *_textField;}+(PasswordInputWindow *)shareInstance{    static id shareInstance=nil;    static dispatch_once_t onceToken;    dispatch_once(&onceToken,^{                shareInstance=[[self alloc] initWithFrame:[[UIScreen mainScreen] bounds]];    });    return shareInstance;}-(id)initWithFrame:(CGRect)frame{    self=[super initWithFrame:frame];    if (self) {                UILabel *label=[[UILabel alloc]initWithFrame:CGRectMake(10, 50, 200, 20)];        label.text=@"請輸入密碼";        [self addSubview:label];                UITextField *textField=[[UITextField alloc]initWithFrame:CGRectMake(10, 80, 200, 20)];        textField.backgroundColor=[UIColor whiteColor];        textField.secureTextEntry=YES;        [self addSubview:textField];                        UIButton *button=[[UIButton alloc] initWithFrame:CGRectMake(10, 110, 200, 44)];        [button setBackgroundColor:[UIColor blueColor]];        button.titleLabel.textColor=[UIColor blackColor];        [button setTitle:@"確定" forState:UIControlStateNormal];        [button addTarget:self action:@selector(completeButtonPRessed:) forControlEvents:UIControlEventTouchUpInside];        [self addSubview:button];                        self.backgroundColor=[UIColor yellowColor];        _textField=textField;    }    return self;}-(void)show{    [self makeKeyAndVisible];    self.hidden=NO;}-(void)completeButtonPressed:(id)sender{    if ([_textField.text isEqualToString:@"abcd"]) {        [_textField resignFirstResponder];        [self resignFirstResponder];        self.hidden=YES;    }else{        [self showErrorAlertView];    }}-(void)showErrorAlertView{    UIAlertView *alertView=[[UIAlertView alloc]initWithTitle:nil message:@"密碼錯誤，正確密碼是abcd" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];    [alertView show];}@end