UIAlertController

1.创建UIAlertController

UIAlertController *alertController = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];

2.创建UIAlertAction

        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];
            }
        }];

3.把创建的UIAlertAction添加到UIAlertController里。

        [alertController addAction:cancelAction];
        [alertController addAction:fromCameraAction];
        [alertController addAction:fromPhotoAction];

4.显示提示框

        [self presentViewController:alertController animated:YES completion:nil];