带有解析查询的 UITableView 未加载

Question

所以我有一个 UITableView 和一个 Parse 查询，并且该查询能够从 parse 中检索对象。但是 TableView 没有显示它们。

这是我的代码，我将在下面详细解释：

- (PFQuery *)query {
    NSLog(@"hello");
    PFQuery *query = [PFQuery queryWithClassName:@"Posts"];

    // If no objects are loaded in memory, we look to the cache first to fill the table
    // and then subsequently do a query against the network.


    // Query for posts near our current location.

    // Get our current location:
    //CLLocation *currentLocation = [self.dataSource currentLocationForWallPostsTableViewController:self];
    CLLocationAccuracy filterDistance = [[NSUserDefaults standardUserDefaults] doubleForKey:PAWUserDefaultsFilterDistanceKey];

    // And set the query to look by location
    PFGeoPoint *point = [PFGeoPoint geoPointWithLatitude:40.941984
                                               longitude:-72.88712399999997];
    [query whereKey:PAWParsePostLocationKey nearGeoPoint:point withinKilometers:PAWMetersToKilometers(filterDistance)];
    [query includeKey:PAWParsePostUserKey];

    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (!error) {
            // The find succeeded.
            NSLog(@"Successfully retrieved %lu users.", (unsigned long)objects.count);
            self.myArray = objects;
        } else {
            // Log details of the failure
            NSLog(@"Error: %@ %@", error, [error userInfo]);
        }
    }];


    NSLog(@"work");

    return query;
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}



- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    // Return the number of sections.
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{

    return self.myArray.count;
}


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath object:(PFObject *)object {
    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
    }
    NSLog(@"yy");
    NSString *kk= [object objectForKey:@"text"];
    NSLog(@"%@",kk);
    // Configure the cell
    cell.textLabel.text = [object objectForKey:@"text"];

    return cell;
}

我发现可能导致问题的两件事是：

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section 在查询之前被调用，这对我来说没有意义。
并且因为在查询之前被调用，所以 array.count 是 0；

所以我不明白为什么在查询之前会调用该行。如果您有任何建议，请告诉我！

Update这个被调用了三次，第二次nslog没有被调用

 - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
    {
        NSLog(@"Fsa");
        return self.myArray.count;
        NSLog(@"Successfully retrieved %lu .", (unsigned long)self.myArray.count);

    }

在我的.h

UIViewController <UITableViewDataSource, UITableViewDelegate>
@property (weak, nonatomic) IBOutlet UITableView *tableView;

Answer 1

尝试在 viewDidLoad 中显式调用它。提供 self.myArray = objects 不 return nil 这应该足够了。它将强制加载规避其他方法首先加载：

-(void)viewDidLoad {
    ...
    [self locationQuery];
}

-(PFQuery *)locationQuery {

    CLLocationAccuracy filterDistance = [[NSUserDefaults standardUserDefaults] doubleForKey:PAWUserDefaultsFilterDistanceKey];
    PFGeoPoint *point = [PFGeoPoint geoPointWithLatitude:40.941984
                                           longitude:-72.88712399999997];

    PFQuery *query = [PFQuery queryWithClassName:@"Posts"];
    [query whereKey:PAWParsePostLocationKey nearGeoPoint:point withinKilometers:PAWMetersToKilometers(filterDistance)];
    [query includeKey:PAWParsePostUserKey];
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
            if (!error) {
                // The find succeeded.
                NSLog(@"Successfully retrieved %lu users.", (unsigned long)objects.count); 
                self.myArray = objects;
                //OR : 
                self.myArray = [objects valueForKey:@"NameOfParse.comClassColumnHere"];
                [self.tableView reloadData];
            } else {
                // Log details of the failure
                NSLog(@"Error: %@ %@", error, [error userInfo]);
            }
     }];
        return query;
}

此外，您的 cell.textLabel.text 引用了不存在的内容..

NSString *kk= [object objectForKey:@"text"]; NSLog(@"%@",kk); // Configure the cell cell.textLabel.text = [object objectForKey:@"text"];

这是什么？如果你想让它成为你查询的数组，你必须这样做：

cell.textLabel.text = [NSString stringWithFormat:@"%@", [self.myArray objectAtIndex:indexPath.row]];

Answer 2

试试这个：

[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
    if (!error) {
        // The find succeeded.
        NSLog(@"Successfully retrieved %lu users.", (unsigned long)objects.count);
        self.myArray = objects;
        dispatch_async(dispatch_get_main_queue(), ^{
            [self.tableView reloadData];
        });

    } else {
        // Log details of the failure
        NSLog(@"Error: %@ %@", error, [error userInfo]);
    }
}];

Answer 3

此方法：

- (PFQuery *)queryForTable

returns 一个自动填充 PFObject in cellForRowAtIndexPath:object: in

的查询

- (UITableViewCell *)tableView:(UITableView *)tableView
   cellForRowAtIndexPath:(NSIndexPath *)indexPath object:(PFObject *)object {

但是，您所做的是在 queryForTable 方法中执行 query。 (1) 您不需要执行查询，您只需要 return 它，但是 (2) 似乎您正在严格执行该查询以填充 self.myArray然后将其用作 numberOfRowsInSection: 中的 return 值。 #2 的问题是您在 queryForTable 中执行的查询是异步执行的，因此在调用 numberOfRowsInSection: 时 self.myArray 可能仍为空。这就是正在发生的事情 - self.myArray.count = 0 因此 cellForRowAtIndexPath: 不会被调用。

但最大的问题 #3 是 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath object:(PFObject *)object 只能用在 PFQueryTableViewController 中，所以你必须使用查询和标准 UITableView委托方法代替。

试试这个：

- (void)viewDidLoad {

    NSLog(@"hello");
    PFQuery *query = [PFQuery queryWithClassName:@"Posts"];

    // Query for posts near our current location.

    // Get our current location:
    //CLLocation *currentLocation = [self.dataSource currentLocationForWallPostsTableViewController:self];
    CLLocationAccuracy filterDistance = [[NSUserDefaults standardUserDefaults] doubleForKey:PAWUserDefaultsFilterDistanceKey];

    // And set the query to look by location
    PFGeoPoint *point = [PFGeoPoint geoPointWithLatitude:40.941984
                                               longitude:-72.88712399999997];
    [query whereKey:PAWParsePostLocationKey nearGeoPoint:point withinKilometers:PAWMetersToKilometers(filterDistance)];
    [query includeKey:PAWParsePostUserKey];

    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (!error) {
            // The find succeeded.
            NSLog(@"Successfully retrieved %lu users.", (unsigned long)objects.count);
            self.myArray = objects;

            dispatch_async(dispatch_get_main_queue(), ^{
                [self.tableView reloadData];
            });

        } else {
            // Log details of the failure
            NSLog(@"Error: %@ %@", error, [error userInfo]);
        }
    }];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    // Return the number of sections.
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return self.myArray.count;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
    }
    NSLog(@"yy");
    NSString *kk= [[self.myArray objectAtIndex:indexPath.row] objectForKey:@"text"];
    NSLog(@"%@",kk);
    // Configure the cell
    cell.textLabel.text = [[self.myArray objectAtIndex:indexPath.row] objectForKey:@"text"];

    return cell;
}

带有解析查询的 UITableView 未加载

UITableView With Parse Query Not Loading

ios

objective-c

iphone

uitableview

parse-platform