Question

我被困住了。我打电话给PFQuery和我NSlog我的“类别” 这一切在调试器区域都很好。

我遇到麻烦的地方是使用这些数据从Parse.com填充我的UIPickerView。

这是我想出的。

请注意，我已经为Picker提供了必要的方法，我只需要使用解析中的数据来填充它。

_pickerData是一个填充选择器的NSArray，我认为我可以等于填充对象，但这不起作用。

编辑：到目前为止我有什么......

 - (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.


    PFQuery *query = [PFQuery queryWithClassName:@"Categories"];
    [query whereKeyExists:@"Category"];
    [query orderByDescending:@"createdAt"];
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (!error) {
            _pickerData = objects;

            NSLog(@"%@",objects);
        }
        else {
            NSLog(@"error");
        }
    }];


    self.categoryPicker.dataSource = self;
    self.categoryPicker.delegate = self;


}


// The number of columns of data
- (int)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
    return 1;
}

// The number of rows of data
- (int)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
    return _pickerData.count;
}

// The data to return for the row and component (column) that's being passed in
- (NSString*)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    return _pickerData[row];
}

Answer 1

在将objects分配给_pickerData

后重新加载您的选择器视图

PFQuery *query = [PFQuery queryWithClassName:@"Categories"];
[query whereKeyExists:@"Category"];
[query orderByDescending:@"createdAt"];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
    if (!error) {
        _pickerData = objects;

      [_categoryPicker reloadData];

      NSLog(@"%@",objects);
    }
    else {
        NSLog(@"error");
    }
}];

Answer 2

PFQuery *query = [PFQuery queryWithClassName:@"Categories"];
    [query whereKeyExists:@"Category"];
    [query orderByDescending:@"createdAt"];
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (!error) {
            _pickerData = objects;

             // update pickerView
             [categoryPicker reloadAllComponents];

            NSLog(@"%@",objects);
        }
        else {
            NSLog(@"error");
        }
    }];

在加载数据后使用[categoryPicker reloadAllComponents];更新pickerView。

修改

设置代表＆amp;资源 //连接数据

self.categoryPicker.dataSource = self; self.categoryPicker.delegate = self;

添加方法：

// The number of columns of data - (int)numberOfComponentsInPickerView:(UIPickerView *)pickerView { return 1; } // The number of rows of data - (int)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component { return _pickerData.count; } // The data to return for the row and component (column) that's being passed in - (NSString*)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component { return _pickerData[row]; }

Answer 3

试试这个，如上所述，你需要在查询找到对象并加载数组后重新加载pickerView。另请注意，这是一个PFObjects数组，你必须使用标题的键值，你不能只插入一个PFObject来进行titleForRow：DataSource调用。

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    self.categoryPicker.dataSource = self;
    self.categoryPicker.delegate = self;

    PFQuery *query = [PFQuery queryWithClassName:@"Categories"];
    [query whereKeyExists:@"Category"];
    [query orderByDescending:@"createdAt"];
    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (!error) {
            _pickerData = objects;
            [self.categoryPicker reloadAllComponents];
        }
        else {
            NSLog(@"error");
        }
    }];
}


// The number of columns of data
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
    return 1;
}

// The number of rows of data
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
    return _pickerData.count;
}

// The data to return for the row and component (column) that's being passed in
- (NSString*)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    PFObject *object = _pickerData[row];
    //Assuming "Category" is a string here for your title
    return object[@"Category"];
}

如何使用Parse.com填充UIPickerView

3 个答案: