我有一个UIAlertView，它在iOS 7中完美显示，但在iOS 8中，不显示任何按钮或标签。警告仍然可见，但只是一个小白框。
OK和cancel按钮也会响应事件，但没有文字可见。
我已经使用这个警告来在点击按钮时显示。
- (IBAction)sel_btnLogout:(id)sender {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Logout!" message:@"Are you sure you want to logout?" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"Ok", nil];
[alert show];
}
我在iOS 8中检查了框架：它给出的是（0,0,0,0），但在iOS 7中它会给出一个确定的值。
我还检查了遍历uialertview子视图的情况。在iOS7中，它进入循环，因为它找到了alert的子视图。在iOS8中，它说alertView没有子视图。
检查类是否可用
if ([UIAlertController class])
{
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"Alert title" message:@"Alert message" preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction* ok = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:nil];
[alertController addAction:ok];
[self presentViewController:alertController animated:YES completion:nil];
}
else
{
UIAlertView * alert = [[UIAlertView alloc]initWithTitle:@"Alert title" message:@"Alert message" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
[alert show];
}
iOS 8 允许你设置标题而不是消息：
[[[UIAlertView alloc] initWithTitle:@"AlertView in iOS 8." message:nil delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil]show];
从iOS 8开始，UIAlertView已经被废弃。如果需要更多信息，请访问http://nshipster.com/uialertcontroller/ 或者https://developer.apple.com/LIBRARY/IOS/documentation/UIKit/Reference/UIAlertViewDelegate_Protocol/index.html
因此，如果你要为iOS 7和iOS 8编写单独的代码，应该使用UIAlertController代替UIAlertView:
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"AlertView in iOS 8" message:nil preferredStyle:UIAlertControllerStyleAlert];
[alertController addAction:[UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) {
[self dismissViewControllerAnimated:YES completion:nil];
}]];
[self presentViewController:alertController animated:YES completion:nil];
UIAlertView完美地实现。 - rmaddy- (IBAction)UIAlertControllerWithActionSheetTextFields:(id)sender {
UIAlertController * alert= [UIAlertController
alertControllerWithTitle:@"Info"
message:@"You are using UIAlertController with Actionsheet and text fields"
preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction* ok = [UIAlertAction
actionWithTitle:@"OK"
style:UIAlertActionStyleDefault
handler:^(UIAlertAction * action)
{
NSLog(@"Resolving UIAlert Action for tapping OK Button");
[alert dismissViewControllerAnimated:YES completion:nil];
}];
UIAlertAction* cancel = [UIAlertAction
actionWithTitle:@"Cancel"
style:UIAlertActionStyleDefault
handler:^(UIAlertAction * action)
{
NSLog(@"Resolving UIAlertActionController for tapping cancel button");
[alert dismissViewControllerAnimated:YES completion:nil];
}];
[alert addAction:ok];
[alert addAction:cancel];
[alert addTextFieldWithConfigurationHandler:^(UITextField * textField) {
textField.accessibilityIdentifier = @"usernameTextField";
textField.placeholder = @"Enter your username";
textField.accessibilityLabel = @"usernameLabel";
}];
[alert addTextFieldWithConfigurationHandler:^(UITextField * textField) {
textField.placeholder = @"Enter your password";
textField.accessibilityIdentifier = @"paswordTextField";
textField.accessibilityLabel = @"passwordLabel";
}];
[self presentViewController:alert animated:YES completion:nil];
}如果您需要一个项目来完整地了解IOS中可用的警报类型，请访问以下URL查看我的项目：
iOS 8中，您需要使用UIAlertController 替换 UIAlertView 和 UIActionSheet。请先阅读苹果论坛中的文档：
苹果Alertcontroller
if (([[[UIDevice currentDevice] systemVersion] compare:@"8.0" options:NSNumericSearch] == NSOrderedAscending))
{
// use UIAlertView
UIAlertView *alert = [[UIAlertView alloc]initWithTitle:Title message:desc delegate:nil cancelButtonTitle:@"OK" otherButtonTitles: nil];
[alert show];
}
else {
// use UIAlertController
UIAlertController *alert = [UIAlertController alertControllerWithTitle:Title message:desc preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction *okAction = [UIAlertAction actionWithTitle:@"OK" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
}];
[alert addAction:okAction];
[self presentViewController:alert animated:YES completion:nil];
}
let alert = UIAlertController(title: "Warning" as String , message: messageString as String, preferredStyle: .Alert)
let okAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.Default)
{
UIAlertAction in
self.dismissViewControllerAnimated(true, completion: nil)
}
// Add the actions
alert.addAction(okAction)
self.presentViewController(alert, animated: true, completion: nil)
我认为这不是UIAlertview的问题。请检查这个是否正常运作。
我认为你的代码有问题......
在任何视图控制器中，请将此代码放在viewDidLoad中，如下所示：
- (void)viewDidLoad
{
[super viewDidLoad];
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Title" message:@"My message" delegate:self cancelButtonTitle:@"Cancel" otherButtonTitles:@"Ok", nil];
[alert show];
}
viewDidLoad 方法中不要显示警告。因为视图还没有显示出来。