如何在IOS 8中设置UIAlertController的高度和宽度

Question

我有一个带有TextFile的UIAlertController。问题是默认的UIAlertController是一个非常小的尺寸。它的文字无法正常看到。

所以，我想增加UIAlertController的高度和宽度。换句话说，我想创建一个自定义的UIAlertController。这样做的方法是什么？

Answer 1

我不认为你可以设置大小。不好的解决方法是，在邮件上设置\n。 UIAlertView也有同样的限制。

我建议使用UIPopoverController并实现自己的dismiss按钮，因为UIAlertController的目的是为每个Apple文档向用户显示警报消息（短消息）。我不认为消息墙可以被视为警报消息。

一般来说，我认为这个限制是由Apple设定的，提醒这个视图是向用户显示短信，作为其用户体验的一部分。

用示例代码编辑首先，抱歉，我的意思是UIPopoverPresentViewController，而不是UIPopoverController

这是示例类：

@interface DemoPopOverPresentViewController : UIViewController

- (instancetype)initWithTitle:(NSString*)title message:(NSString*)message buttonTitle:(NSString*)buttonTitle;

@property NSString* titleText;
@property NSString* messageText;
@property NSString* buttonTitleText;

@property UILabel* titleLabel;
@property UILabel* textLabel;
@property UIButton* submitButton;

@end

@implementation DemoPopOverPresentViewController

- (instancetype)initWithTitle:(NSString*)title message:(NSString*)message buttonTitle:(NSString*)buttonTitle;
{
    self = [super init];

    if ( self ) {
        _titleText = title;
        _messageText = message;
        _buttonTitleText = buttonTitle;
    }

    return self;
}

- (void)viewDidLoad;
{
    [super viewDidLoad];

    _titleLabel = [UILabel new];
    [_titleLabel setTextAlignment:NSTextAlignmentCenter];
    [_titleLabel setFont:[UIFont preferredFontForTextStyle:UIFontTextStyleHeadline]];
    [_titleLabel setTranslatesAutoresizingMaskIntoConstraints:NO];
    [_titleLabel setText:_titleText];
    [self.view addSubview:_titleLabel];
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"|[_titleLabel]|"     options:0 metrics:nil views:NSDictionaryOfVariableBindings(_titleLabel)]];

    _textLabel = [UILabel new];
    [_textLabel setTextAlignment:NSTextAlignmentCenter];
    [_textLabel setFont:[UIFont preferredFontForTextStyle:UIFontTextStyleBody]];
    [_textLabel setTranslatesAutoresizingMaskIntoConstraints:NO];
    [_textLabel setNumberOfLines:0];
    [_textLabel setText:_messageText];
    [self.view addSubview:_textLabel];
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"|[_textLabel]|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(_textLabel)]];

    _submitButton = [UIButton buttonWithType:UIButtonTypeSystem];
    [_submitButton setTitle:_buttonTitleText forState:UIControlStateNormal];
    [_submitButton addTarget:self action:@selector(submitButtonTouched:) forControlEvents:UIControlEventTouchUpInside];
    [_submitButton setTranslatesAutoresizingMaskIntoConstraints:NO];
    [self.view addSubview:_submitButton];
    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"|[_submitButton]|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(_submitButton)]];

    [self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|-[_titleLabel(<=44.0)]-16-[_textLabel]-16-[_submitButton(<=44.0)]-|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(_titleLabel,_textLabel,_submitButton)]];
}

- (void)submitButtonTouched:(id)sender;
{
    [self dismissViewControllerAnimated:YES completion:^{

    }];
}

@end

然后在presentViewController上，

• 首先，它需要实现UIPopoverPresentationControllerDelegate委托
• 然后初始化类：

  DemoPopOverPresentViewController* controller = [[DemoPopOverPresentViewController alloc] initWithTitle:@"Info" message:@"The quick brown fox jumps over the lazy dog" buttonTitle:@"Dismiss"];
  controller.modalPresentationStyle = UIModalPresentationPopover;
  // set the content size of your 'alert view'
  controller.preferredContentSize = CGSizeMake(200.0, 150.0);
  UIPopoverPresentationController* pc = [controller popoverPresentationController];
  pc.sourceView = self.view;
  pc.delegate = self;
  pc.sourceRect = CGRectMake(self.view.frame.size.width/2.0, self.view.frame.size.height/2.0, 0.0, 0.0);
  pc.permittedArrowDirections = NULL;
  [self presentViewController:controller animated:YES completion:^{
  
  }];

• 实现UIPopoverPresentationControllerDelegate的委托方法：- (UIModalPresentationStyle)adaptivePresentationStyleForPresentationController:(UIPresentationController *)controller并返回UIModalPresentationNone

Answer 2

我知道这已关闭但我发现你可以像这样添加alertviewcotnroller.view的约束

var height:NSLayoutConstraint = NSLayoutConstraint(item: alertController.view, attribute: NSLayoutAttribute.Height, relatedBy: NSLayoutRelation.Equal, toItem: nil, attribute: NSLayoutAttribute.NotAnAttribute, multiplier: 1, constant: self.view.frame.height * 0.80)
    alertController.view.addConstraint(height);

Answer 3

UIAlertController *alert = [UIAlertController alertControllerWithTitle:title message:message preferredStyle:UIAlertControllerStyleAlert];
[alert addAction:[UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {

}]];


UIViewController *viewController = [[[[UIApplication sharedApplication] delegate] window] rootViewController];

if ( viewController.presentedViewController && !viewController.presentedViewController.isBeingDismissed ) {
    viewController = viewController.presentedViewController;
}

**NSLayoutConstraint *constraint = [NSLayoutConstraint constraintWithItem:alert.view attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationLessThanOrEqual toItem:nil attribute:NSLayoutAttributeNotAnAttribute multiplier:1 constant:viewController.view.frame.size.height*0.8f];
[alert.view addConstraint:constraint];**

[viewController presentViewController:alert animated:YES completion:^{

}];

Answer 4

这当然可以帮到你。 （斯威夫特4.2）

let alert = UIAlertController(title: "Alert", message: "Some message", preferredStyle: .actionSheet)

alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: { (action) in

}))
alert.addAction(UIAlertAction(title: "Some", style: .default))
alert.addAction(UIAlertAction(title: "Some", style: .default))

let height:NSLayoutConstraint = NSLayoutConstraint(item: alert.view, attribute: NSLayoutConstraint.Attribute.height, relatedBy: NSLayoutConstraint.Relation.equal, toItem: nil, attribute: NSLayoutConstraint.Attribute.notAnAttribute, multiplier: 1, constant: view.frame.height)
alert.view.addConstraint(height);
present(alert, animated: true)