UIAlertControllerStyleActionShee

ActionSheet样式弹框:

UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"title" message:@"message" preferredStyle:UIAlertControllerStyleActionSheet];
    
    UIAlertAction *action = [UIAlertAction actionWithTitle:@"act1" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        
    }];
    UIAlertAction *action2 = [UIAlertAction actionWithTitle:@"act2" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        
    }];
    UIAlertAction *cancle = [UIAlertAction actionWithTitle:@"cancle" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
        
    }];
    [alert addAction:action];
    [alert addAction:action2];
    [alert addAction:cancle];
    [self presentViewController:alert animated:YES completion:nil];

设置仅在iPhone: 路径: TARGETS -> Development Info -> Devices

Snip20171208_3.png

上面创建UIAlertControllerStyleActionSheet样式弹框的代码在iPhone手机上运行时没有问题，运行效果如图(四周存在黑边是因为Xcode设置仅在iPhone运行 而模拟器放在了iPad上不适配所致): 此时可看到UIAlertControllerStyleActionSheet运行效果iPhone与iPad效果一致.

Simulator Screen Shot - iPad Pro (9.7 inch) - 2017-12-08 at 14.21.09.png

设置Universal:

Snip20171208_2.png

设置机型为Universal(即: 手机和iPad均支持) 在iPhone上运行效果与上一致，而在iPad上运行时 导致崩溃

报错信息:

Your application has presented a UIAlertController (<UIAlertController: 0x100b790f0>) of style UIAlertControllerStyleActionSheet. The modalPresentationStyle of a UIAlertController with this style is UIModalPresentationPopover. You must provide location information for this popover through the alert controller's popoverPresentationController. You must provide either a sourceView and sourceRect or a barButtonItem. If this information is not known when you present the alert controller, you may provide it in the UIPopoverPresentationControllerDelegate method -prepareForPopoverPresentation.

解决:

UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"title" message:@"message" preferredStyle:UIAlertControllerStyleActionSheet];
    
    UIAlertAction *action = [UIAlertAction actionWithTitle:@"act1" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        
    }];
    UIAlertAction *action2 = [UIAlertAction actionWithTitle:@"act2" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        
    }];
    UIAlertAction *cancle = [UIAlertAction actionWithTitle:@"cancle" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
        
    }];
    [alert addAction:action];
    [alert addAction:action2];
    [alert addAction:cancle];
    
    UIPopoverPresentationController *popover = alert.popoverPresentationController;
    if (popover)
    {
        popover.sourceView = self.view;
        popover.sourceRect = CGRectMake(0, 0, 100, 100);
        popover.permittedArrowDirections = UIPopoverArrowDirectionAny;
    }
    
    [self presentViewController:alert animated:YES completion:nil];

Simulator Screen Shot - iPad Pro (9.7 inch) - 2017-12-08 at 14.21.34.png