UITextField没有出现在iOS8中

Question

因此，我最近为iOS 6开发了一个可读取PDF的应用程序。它在我的iPhone 3GS上运行良好，但是当我在较新版本的Xcode (最初使用4.5，现在使用6.01)为iOS 8重新编译它时，输入您想要加载的PDF名称的文本字段不再显示它应该加载的位置。

当用户按下打开键时，出现在警告框中的文本字段。

下面是在iOS 6中工作的代码

    alert = [[UIAlertView alloc]initWithTitle:@"Please enter a valid PDF name below:" message:@"(Please add .PDF on the end!) \n \n" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"ok", nil];
    textField = [[UITextField alloc] initWithFrame:CGRectMake(10, 200, 300, 40)];
    [textField setBackgroundColor:[UIColor whiteColor]];
    textField.delegate = nil;
    textField.borderStyle = UITextBorderStyleRoundedRect;
    textField.placeholder = @"PDF name";
    textField.tintColor = [UIColor colorWithRed:98.0/255.0f green:98.0/255.0f blue:98.0/255.0f alpha:1.0];
    textField.keyboardAppearance = UIKeyboardAppearanceAlert; //set up an alert box with a text feild
    [textField becomeFirstResponder];
    [alert addSubview:textField];
    [alert show];
    [alert release];

Answer 1

试着遵循代码！！

    UIAlertController * alertView=   [UIAlertController
                                      alertControllerWithTitle:@"Please enter a valid PDF name below:"
                                      message:@"Please add .PDF on the end!"
                                      preferredStyle:UIAlertControllerStyleAlert];

    [alertView addTextFieldWithConfigurationHandler:^(UITextField *textField) {
        textField.placeholder = @"PDF name";

    }];

    UIAlertAction* yesButton = [UIAlertAction
                                actionWithTitle:@"Ok"
                                style:UIAlertActionStyleDefault
                                handler:^(UIAlertAction * action)
                                {
                                    //Handel your yes please button action here
                                    UITextField *textField = alertView.textFields[0];
                                    NSString *pdfName = textField.text;
                                    NSLog(@"PDF Name: %@",pdfName);
                                    [alertView dismissViewControllerAnimated:YES completion:nil];


                                }];
    UIAlertAction* noButton = [UIAlertAction
                               actionWithTitle:@"Cancel"
                               style:UIAlertActionStyleDefault
                               handler:^(UIAlertAction * action)
                               {
                                   //Handel no, thanks button
                                   [alertView dismissViewControllerAnimated:YES completion:nil];
                               }];

    [alertView addAction:yesButton];
    [alertView addAction:noButton];
    [self presentViewController:alertView animated:YES completion:nil];