如何在UIAlertController中放置UIActivityIndicatorView？ [英] How do I put a UIActivityIndicatorView in a UIAlertController?
问题描述
我们正在离开MBProgressHUD，因为它在我们的应用程序中太麻烦了，并且没有阻止用户输入或提供取消按钮等功能。
那么，我试图实现一样，有一个名为的属性contentViewController 我们可以使用KVC进行访问
示例：
UIViewController * v = [[UIViewController alloc] init];
v.view.backgroundColor = [UIColor redColor];
[alertController setValue：v forKey：@contentViewController];
所以这里是你的代码应该是这样的（测试并且工作正常）：
- （IBAction）buttonClicked：（id）sender
{
self.alertController = [UIAlertController alertControllerWithTitle： @正在加载
消息：nil
preferredStyle：UIAlertControllerStyleAlert];
[self.alertController addAction：[UIAlertAction actionWithTitle：@Cancelstyle：UIAlertActionStyleCancel handler：nil]];
UIViewController * customVC = [[UIViewController alloc] init];
UIActivityIndicatorView * spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle：UIActivityIndicatorViewStyleGray];
[spinner startAnimating];
[customVC.view addSubview：spinner];
[customVC.view addConstraint：[NSLayoutConstraint
constraintWithItem：spinner
attribute：NSLayoutAttributeCenterX
relatedBy：NSLayoutRelationEqual
toItem：customVC.view
属性：NSLayoutAttributeCenterX
乘数：1.0f
常数：0.0f]];
[customVC.view addConstraint：[NSLayoutConstraint
constraintWithItem：spinner
attribute：NSLayoutAttributeCenterY
relatedBy：NSLayoutRelationEqual
toItem ：customVC.view
属性：NSLayoutAttributeCenterY
乘数：1.0f
常数：0.0f]];
[self.alertController setValue：customVC forKey：@contentViewController];
[self presentViewController：self.alertController
animated：true
completion：nil];
}
您可以覆盖
-preferredContentSize返回您设置为contentViewController的
视图控制器中的自定义大小。
在我们的例子中它是 customVC
结果：
希望文字低于指标？
I使用 xib 创建了一个 UIViewController ，作为我们的 contentViewController的自定义控制器在第一个例子中我们创建了没有xib文件的视图控制器，现在我们可以使用界面构建器添加视图，我添加了一个活动指示器并将约束设置为水平和垂直居中以及活动下的标签这里水平居中的指标是我的界面构建器：
我们现在有更少的代码：
- （IBAction）buttonClicked：（id）sender
{
self.alertController = [UIAlertController alertControllerWithTitle：nil
message：nil
preferredStyle：UIAlertControllerStyleAlert];
MyCustomViewController * v = [[MyCustomViewController alloc] init];
[self.alertController setValue：v forKey：@contentViewController];
[self presentViewController：self.alertController animated：true completion：nil];
}
结果：
We're moving away from MBProgressHUD because it's too glitchy in our app, and doesn't have features such as blocking user input or providing a Cancel button.
So, I've attempted to implement Swipesight's How to display activity indicator in center of UIAlertController?, and I ran into improper positioning of the indicator:
It is green because our app's tint is green.
As you can see, it's not in the white rectangle part of the controller, but the grey background. This uses something similar to his "@62Shark" solution:
// in implementation:
@property (nonatomic, strong) UIActivityIndicatorView *spinner;
@property (nonatomic, strong) UIAlertController *alertController;
// in init:
_alertController = [UIAlertController alertControllerWithTitle: @"Loading"
message: nil
preferredStyle: UIAlertControllerStyleAlert];
_spinner = [UIActivityIndicatorView new];
_spinner.translatesAutoresizingMaskIntoConstraints = false;
_spinner.userInteractionEnabled = false;
_spinner.color = [ThemingAssistant tintColor];
_spinner.frame = _alertController.view.bounds;
_spinner.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
[_spinner startAnimating];
[_alertController.view addSubview: _spinner];
// ...
- (void) showOn: (UIViewController *)target
title: (NSString *)title
message: (NSString *)message
canCancel: (BOOL)canCancel
{
self.alertController.title = title;
self.alertController.message = message;
if (canCancel)
{
[self.alertController addAction:[UIAlertAction actionWithTitle: @"Cancel"
style: UIAlertActionStyleCancel
handler: ^(UIAlertAction *name){
[self customDismiss];
}]];
}
NSDictionary *views = @{@"pending" : self.alertController.view,
@"indicator" : self.spinner};
NSArray *constraints =
[NSLayoutConstraint constraintsWithVisualFormat: @"V:[indicator]-(-50)-|"
options: 0
metrics: nil
views: views];
[constraints arrayByAddingObjectsFromArray:
[NSLayoutConstraint constraintsWithVisualFormat: @"H:|[indicator]|"
options: 0
metrics: nil
views: views]];
[target presentViewController: self.alertController
animated: true
completion: nil];
}
Even if this was in the white rectangle, I fear it might run into text (also, when I get it in there, I want it to be in the middle-top, much like MBProgressHUD does), so I'll need a way to reserve some space for it.
So, my question is two-fold: How do I reserve space for a UIActivityIndicatorView in a UIAlertController's white rectangle, and then how do I actually place it in there?
Like JonasG mentioned here there is a property named contentViewController and we can use KVC for access
Example :
UIViewController *v = [[UIViewController alloc] init];
v.view.backgroundColor = [UIColor redColor];
[alertController setValue:v forKey:@"contentViewController"];
So here is how your code should looks like (tested and works fine) :
- (IBAction)buttonClicked:(id)sender
{
self.alertController = [UIAlertController alertControllerWithTitle: @"Loading"
message: nil
preferredStyle: UIAlertControllerStyleAlert];
[self.alertController addAction:[UIAlertAction actionWithTitle: @"Cancel" style: UIAlertActionStyleCancel handler:nil]];
UIViewController *customVC = [[UIViewController alloc] init];
UIActivityIndicatorView* spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
[spinner startAnimating];
[customVC.view addSubview:spinner];
[customVC.view addConstraint:[NSLayoutConstraint
constraintWithItem: spinner
attribute:NSLayoutAttributeCenterX
relatedBy:NSLayoutRelationEqual
toItem:customVC.view
attribute:NSLayoutAttributeCenterX
multiplier:1.0f
constant:0.0f]];
[customVC.view addConstraint:[NSLayoutConstraint
constraintWithItem: spinner
attribute:NSLayoutAttributeCenterY
relatedBy:NSLayoutRelationEqual
toItem:customVC.view
attribute:NSLayoutAttributeCenterY
multiplier:1.0f
constant:0.0f]];
[self.alertController setValue:customVC forKey:@"contentViewController"];
[self presentViewController: self.alertController
animated: true
completion: nil];
}
You can override
-preferredContentSizeto return a custom size in the view controller that you are setting ascontentViewController.
in our case it's customVC
Result:
Want the text to be below the indicator ?
I have created a UIViewController with an xib to act as a custom controller for our contentViewController in the first example we have created the view controller without xib file, Now we can add views using interface builder, I have added an Activity indicator and set the constraints to be centered horizontally and vertically and a label under the activity indicator which is centered horizontally here is my interface builder:
we have less code now:
- (IBAction)buttonClicked:(id)sender
{
self.alertController = [UIAlertController alertControllerWithTitle: nil
message: nil
preferredStyle: UIAlertControllerStyleAlert];
MyCustomViewController *v = [[MyCustomViewController alloc] init];
[self.alertController setValue:v forKey:@"contentViewController"];
[self presentViewController: self.alertController animated: true completion: nil];
}
Result :
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