iphone - PickerView 仅返回我的数组中添加的最后一个对象

Question

我正在从一个 JSON 文件中解析一些数据

NSString *filePath = [[NSBundle mainBundle] pathForResource:@"airports" ofType:@"json"];

NSString *jsonData = [[NSString alloc] initWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:NULL];

NSArray *airports = [NSJSONSerialization JSONObjectWithData:[jsonData dataUsingEncoding:NSUTF8StringEncoding] options:0 error:nil];


for (NSDictionary *result in airports)
{

    NSLog(@"%@ ", [result objectForKey:@"name"]);
    airportsArray = [[NSMutableArray alloc]init];
    [airportsArray addObject:[result objectForKey:@"name"]];


}

NSLOG 正确显示所有机场，但当 pickerView 仅显示我文件中的最后一个机场时。

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
return 1
;
}
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:    (NSInteger)component
 {
return [airportsArray count];
}
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row  forComponent:    (NSInteger)component
{
return [airportsArray objectAtIndex:row];
}

更新:感谢您的回复。我修复了我的代码。我只是在 For in 循环中分配数组。

NSString *filePath = [[NSBundle mainBundle] pathForResource:@"airports" ofType:@"json"];

NSString *jsonData = [[NSString alloc] initWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:NULL];

NSArray *airports = [NSJSONSerialization JSONObjectWithData:[jsonData dataUsingEncoding:NSUTF8StringEncoding] options:0 error:nil];

    airportsArray = [[NSMutableArray alloc]init];


for (NSDictionary *result in airports)
{

    NSLog(@"%@ ", [result objectForKey:@"name"]);
    [airportsArray addObject:[result objectForKey:@"name"]];


}

Answer 1

这是因为您在每次循环迭代时都分配 airportsArray。

所以在循环外分配一次:

airportsArray = [[NSMutableArray alloc]init];
for (NSDictionary *result in airports)
{

    NSLog(@"%@ ", [result objectForKey:@"name"]);
    [airportsArray addObject:[result objectForKey:@"name"]];
}