IOS8以上版本，使用UIAlertController代替 UIActionSheet和UIAlertView

苹果在IOS8版本上，新添加了一个UIAlertController用来代替 UIActionSheet 和 UIAlertView；

在工作中，会遇到修改这两个控件按钮颜色的要求，在网上一看，多是采用下边这种方法的：

- (void)willPresentActionSheet:(UIActionSheet *)actionSheet

{

DDLogDebug(@"%@",actionSheet.subviews);

for (UIView *subview
in actionSheet.subviews) {

if ([subview
isKindOfClass:[UIButton
class]]) {

UIButton *button = (UIButton *)subview;

[button
setTitleColor:APP_TINT_COLOR
forState:UIControlStateHighlighted];

[button
setTitleColor:APP_TINT_COLOR
forState:UIControlStateNormal];

[button
setTitleColor:APP_TINT_COLOR
forState:UIControlStateSelected];

}

}

}

但是在IOS8以后，无论是UIActionSheet、UIAlertView还是其他的一些控件的subviews就一直是空，不能返回任何UIView。所以在程序中根据系统版本采用不同的实现方式才是行之有效的，下面是UIAlertController的简单使用：

if ([[XWGlobalHelper
systemVersion] intValue] >
7.99) {
UIAlertController *alertController = [UIAlertController
alertControllerWithTitle:nil

message:nil

preferredStyle:UIAlertControllerStyleActionSheet];

UIAlertAction* cancelAction = [UIAlertAction
actionWithTitle:@"取消"
style:UIAlertActionStyleCancel

handler:^(UIAlertAction * action) {}];

UIAlertAction* fromPhotoAction = [UIAlertAction
actionWithTitle:@"从相册选择"
style:UIAlertActionStyleDefault
handler:^(UIAlertAction * action)
{
UIImagePickerController *imagePicker = [[UIImagePickerController
alloc]
init];
imagePicker.sourceType =
UIImagePickerControllerSourceTypePhotoLibrary;
imagePicker.modalTransitionStyle =
UIModalTransitionStyleCoverVertical;

// imagePicker.allowsEditing = YES;
imagePicker.allowsEditing =
NO;
imagePicker.delegate =
self;
[self
presentViewController:imagePicker
animated:YES
completion:nil];
}];

UIAlertAction* fromCameraAction = [UIAlertAction
actionWithTitle:@"相机"
style:UIAlertActionStyleDefault
handler:^(UIAlertAction * action)
{
if([UIImagePickerController
isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera])
{

UIImagePickerController *imagePicker = [[UIImagePickerController
alloc]
init];
imagePicker.delegate =
self;

// imagePicker.allowsEditing = YES;
imagePicker.allowsEditing =
NO;
imagePicker.modalTransitionStyle =
UIModalTransitionStyleCoverVertical;
imagePicker.sourceType =
UIImagePickerControllerSourceTypeCamera;
[self
presentViewController:imagePicker
animated:YES
completion:nil];
}
}];
[alertController
addAction:cancelAction];
[alertController
addAction:fromCameraAction];
[alertController
addAction:fromPhotoAction];
[self
presentViewController:alertController
animated:YES
completion:nil];
} else {
UIActionSheet * actionSheet = [[UIActionSheet
alloc]
initWithTitle:nil
delegate:self
cancelButtonTitle:@"取消"
destructiveButtonTitle:nil
otherButtonTitles:@"相机",@"从相册选择",
nil];
actionSheet.actionSheetStyle =
UIActionSheetStyleBlackOpaque;
actionSheet.delegate =
self;
[actionSheet
showInView:self.view];

}

上边的UIAlertControllerStyleActionSheet指定了显示效果为之前版本的UIActionSheet，另外还有一个UIAlertControllerStyleAlert指定了显示效果为之前版本的UIAlertView!