ios7 uialertview

- (void) viewDidAppear:(BOOL)animated{
    [super viewDidAppear:animated];
    
    UIAlertView *alertView = [[UIAlertView alloc]
                              //提示标题
                              initWithTitle:@"Password"
                              //提示话
                              message:@"Please enter your password:"
                              //协议
                              delegate:self
                              //取消
                              cancelButtonTitle:@"Cancel"
                              //确认
                              otherButtonTitles:@"Ok", nil];
    //允许用户输入文本
    [alertView setAlertViewStyle:UIAlertViewStyleSecureTextInput];
    //展示
    [alertView show];
    
}