Question

我是xcode的新手，请指导我更正错误，我的代码是，

//Set our mapView
[MapViewC setRegion:myRegion animated:NO];
CLLocation *someLocation=[[CLLocation alloc]initWithLatitude:latitude longitude:longitude];
CLGeocoder *geocoder = [[CLGeocoder alloc] init];
[geocoder reverseGeocodeLocation:someLocation completionHandler:^(NSArray *placemarks, NSError *error) {
    NSDictionary *dictionary = [[placemarks objectAtIndex:0] addressDictionary];
    addressOutlet=[dictionary valueForKey:@"Street"];
    City=[dictionary valueForKey:@"City"];
    State=[dictionary valueForKey:@"State"];

    if (addressOutlet!=NULL&&City!=NULL)
    {
        NSString *SubTitle=[NSString stringWithFormat:@"%@,%@,%@",addressOutlet,City,State];
        cell.detailTextLabel.text=SubTitle;


    }
    else if (addressOutlet==NULL&&City!=NULL)
    {
        NSString *SubTitle=[NSString stringWithFormat:@"%@,%@,",City,State];
        cell.detailTextLabel.text=SubTitle;

    }
    else if (addressOutlet!=NULL&&City==NULL)
    {
        NSString *SubTitle=[NSString stringWithFormat:@"%@,%@,",addressOutlet,State];
        cell.detailTextLabel.text=SubTitle;
    }
    else if(addressOutlet==NULL&&City==NULL)
    {
        NSString *SubTitle=[NSString stringWithFormat:@"%@",State];
        cell.detailTextLabel.text=SubTitle;

    }




}];

提前致谢。

Answer 1

确定数组可以为空，在这种情况下，以下语句将导致异常：

NSDictionary *dictionary = [[placemarks objectAtIndex:0] addressDictionary];
//                                                    ^

所以要防范它，比如：

if ([placemarks count] > 0) {
    NSDictionary *dictionary = [[placemarks objectAtIndex:0] addressDictionary];
    ....
}

我还没有阅读该完成处理程序的API文档，但如果error不是nil，您可以可能测试并相应地采取行动（即， error != nil响应错误，否则处理placemarks数组。

索引0超出空数组的边界'libc ++ abi.dylib：terminate称为抛出异常

1 个答案: