Question

我正在解析JSON文件中的一些数据

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

这是因为您每次循环迭代都会分配AirportsArray 。

所以在循环外部分配一次：

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

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

Answer 2

如果您反复创建机场阵列，会发生什么。在此之前你会破坏它所处的位置。

airportsArray = [[NSMutableArray alloc]init];

将此行移至for...in区块之外。

PickerView仅返回我的数组中添加的最后一个Object

2 个答案: