pad弹出UIAlertControllerStyleActionSheet时，在iphone上运行正常，但在ipad上崩溃，解决代码如下：
UIAlertController *alertVc = [UIAlertController alertControllerWithTitle:@"请选择图片" message:@"" preferredStyle:UIAlertControllerStyleActionSheet];
if (isiPad) {//判断是否为ipad
UIPopoverPresentationController *popover = alertVc.popoverPresentationController;
if (popover) {
popover.sourceView = view;//视图中的某个view
popover.sourceRect = view.bounds;
popover.permittedArrowDirections = UIPopoverArrowDirectionDown;//alertVC弹出的位置
}
}
UIAlertAction *action1 = [UIAlertAction actionWithTitle:@"拍照" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
}];
UIAlertAction *action2 = [UIAlertAction actionWithTitle:@"相册" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
}];
UIAlertAction *action3 = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleDestructive handler:^(UIAlertAction * _Nonnull action) {
[alertVc dismissViewControllerAnimated:YES completion:nil];
}];
[alertVc addAction:action1];
[alertVc addAction:action2];
[alertVc addAction:action3];
[self presentViewController:alertVc animated:YES completion:nil];