UIAlertController在ipad上運行崩潰（ UIAlertController () of style UIAlertCo

 

 

當使用UIAlertController的

UIAlertControllerStyleActionSheet

時在ipad上運行會崩潰，報如下的錯誤：

 reason: 'Your application has presented a UIAlertController (<UIAlertController: 0x1099a7800>) 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.

 

意思就是沒有設置UIAlertController這個彈出窗口的位置信息，能夠經過下面的方式解決，

alertSheetVc.popoverPresentationController.sourceView = self.bgScrollView; 

alertSheetVc.popoverPresentationController.sourceRect =  view.frame;

 或者是經過實現 UIPopoverPresentationControllerDelegate的prepareForPopoverPresentation方法 來設置UIAlertController在當前頁面上的位置信息，設置後的顯示效果與 iPhone是有區別的不是在屏幕的中間位置彈出而是在你所設置的位置彈出：以下圖的界面效果

UIAlertController *alertSheetVc = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];
    alertSheetVc.popoverPresentationController.sourceView = self.bgScrollView;
    
    alertSheetVc.popoverPresentationController.sourceRect =  view.frame;
    
    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"取消" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
        
    }];
    UIAlertAction *albumAction = [UIAlertAction actionWithTitle:@"去相冊選擇" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        [self pushTZImagePickerController];
    }];
    UIAlertAction *cameraAction = [UIAlertAction actionWithTitle:@"拍照" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
        [self takePhoto];
    }];
    [alertSheetVc addAction:cameraAction];
    [alertSheetVc addAction:albumAction];
    [alertSheetVc addAction:cancelAction];
    [self presentViewController:alertSheetVc animated:YES completion:nil];