Parse.com - 如何刷新用户的信息

Question

当我在Parse后端更改例如bool时，我无法在我的iOS应用中检索此值。请参阅以下屏幕截图，其中第一个bool用户对象已手动更改，第二个已从应用程序更改。

第一个不起作用，而一个（从应用程序更改）确实有效。 我使用以下代码获取值：

[[PFUser currentUser] objectForKey:@"is_pro"]

在第一种情况下，返回对象始终是nil（我已经手动更改了bool）。

Answer 1

在您对用户的Parse表进行更改后，请致电

[[PFUser currentUser] fetch]; //synchronous

或

[[PFUser currentUser] fetchInBackground]; //asynchronous

或

[[PFUser currentUser] fetchInBackgroundWithBlock:^(PFObject *object, NSError *error) { //asynchronous with completion block

前

[[PFUser currentUser] objectForKey:@"is_pro"]

获取[PFUser currentUser]对象的更新副本。

注意：refresh和refreshInBackgroundWithBlock:现已弃用，已替换为fetch和fetchInBackgroundWithBlock:

<强>更新

正如Ryan Kreager在评论中指出的那样，使用fetchIfNeeded，fetchIfNeededInBackground或fetchIfNeededInBackgroundWithBlock:＆＃34;可能会更好/更有效率，因为他们会使用可用时的本地缓存。＆＃34;

Answer 2

Swift 中的示例：

首先，请查看isDataAvailable和isDirty。

var user = PFUser.currentUser()!

// Gets whether the PFObject has been fetched.
// isDataAvailable: true if the PFObject is new or has been fetched or refreshed, otherwise false.
user.isDataAvailable()

// Gets whether any key-value pair in this object (or its children) has been added/updated/removed and not saved yet. 
// Returns whether this object has been altered and not saved yet.
user.isDirty()

使用fetchIfNeeded，fetchIfNeededInBackground或fetchIfNeededInBackgroundWithBlock:“可能更好/更有效率，因为他们将在可用时使用本地缓存。”

// Synchronously fetches the PFObject data from the server if isDataAvailable is false.
user.fetchIfNeeded()

// Fetches the PFObject data asynchronously if isDataAvailable is false, then sets it as a result for the task.    
user.fetchIfNeededInBackground()

// Fetches the PFObject data asynchronously if isDataAvailable is false, then calls the callback block.        
user.fetchIfNeededInBackgroundWithBlock({ 
            (object: PFObject?, error: NSError?) -> Void in
    // Code here         
})

否则，如果您不需要使用本地缓存，也可以使用fetch，fetchInBackground，fetchInBackgroundWithBlock。

// Synchronously fetches the PFObject with the current data from the server.
user.fetch()

// Fetches the PFObject asynchronously and sets it as a result for the task.
user.fetchInBackground()

// Fetches the PFObject asynchronously and executes the given callback block.
user.fetchInBackgroundWithBlock({
               (object: PFObject?, error: NSError?) -> Void in
     // Code here
})

Answer 3

当你有指针时，你不能使用fetch。这是最好的方式：

 PFQuery *userQuery = [PFUser query];
    [userQuery includeKey:@"addresses"];
    [userQuery includeKey:@"cards"];
    [userQuery whereKey:@"objectId" equalTo:[PFUser currentUser].objectId];
    [userQuery getFirstObjectInBackgroundWithBlock:^(PFObject * _Nullable object, NSError * _Nullable error) {
}];