Question

说我有一个我正在编辑的PFObject。在稍后阶段，我希望取消我对PFObject所做的更改。如何恢复到PFObject的原始副本？

我尝试了什么

    if (self.request.isDirty) {   // self.request is a PFObject
        // Reload object
        NSLog(@"%@", self.request.requestTitle); // Logs ABC, Original was DEF
        [self.request refreshInBackgroundWithBlock:^(PFObject *object, NSError *error) {
            if (!error) {
                NSLog(@"%@", self.request.requestTitle);   // Logs ABC
                [self.requestDetailsTableView reloadData];
            }
        }];
    }

我也尝试获取对象，但结果相同

    if (self.request.isDirty) {   // self.request is a PFObject
        // Reload object
        NSLog(@"%@", self.request.requestTitle); // Logs ABC, Original was DEF
        [self.request fetchInBackgroundWithBlock:^(PFObject *object, NSError *error) {
            if (!error) {
                NSLog(@"%@", self.request.requestTitle);   // Logs ABC
                [self.requestDetailsTableView reloadData];
            }
        }];
    }

Answer 1

PFObject现在有一种还原方法，只要您没有调用save，就会将对象重置为服务器状态：http://parseplatform.org/Parse-SDK-iOS-OSX/api/Classes/PFObject.html#/c:objc(cs)PFObject(im)revert

例如，我使用带有表单的推送视图控制器来编辑我的PFObject子类的属性，并且我有两个取消和保存按钮...

@IBAction override func cancelAction() {
    self.myObject?.revert()
    self.navigationController?.popViewControllerAnimated(true)
}

@IBAction override func saveAction() {
    self.myObject?.saveInBackgroundWithBlock({ (succeeded: Bool, error: NSError?) -> Void in
        if (succeeded) {
            self.navigationController?.popViewControllerAnimated(true)
        } else {
            // Show error
        }
    })
}

Answer 2

目前没有办法直接执行此操作 - 您需要在通话时做一些花哨的步法：）

试试这个：

if (self.request.isDirty) {   // self.request is a PFObject
    // Reload object
    NSLog(@"%@", self.request.requestTitle); // Logs ABC, Original was DEF
    PFQuery *newRequest = [PFQuery queryWithClassName:@"YourClassName"];
    //Add your request parameters here...

    [newRequest getFirstObjectInBackgroundWithBlock:^(PFObject *object, NSError *error) {
        if (!error) 
            self.request = object;
            NSLog(@"%@", self.request.requestTitle);   // Should log DEF
            [self.requestDetailsTableView reloadData];
        }
    }];
}

撤消/恢复对PFObject的本地更改

2 个答案: