objective-c - ios编程-格式字符串未使用数据参数

Question

当我运行以下代码时，出现Data argument not used by format string 错误:

- (void)pickerView:(UIPickerView *)thePickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {

NSString *colour = ([colourArray objectAtIndex:row]);

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];

[defaults setObject:(colour) forKey:@"colour"];

NSLog(@"NSString =", colour);
NSLog(@"NSUserDefaults =", [defaults objectForKey:@"colour"]);

}

我在 NSLog 两行都收到了错误。此外，这是日志中的内容:

2011-10-25 09:01:50.260 Random[35636:b303] NSString =
2011-10-25 09:01:50.260 Random[35636:b303] NSUserDefaults =

谢谢，亚瑟

Answer 1

NSLog(@"NSString = ", colour);    
NSLog(@"NSUserDefaults =", [defaults objectForKey:@"colour"]);

有问题

应该是

NSLog(@"NSString = %@", colour);
NSLog(@"NSUserDefaults = %@", [defaults objectForKey:@"colour"]);

在这种情况下，格式说明符是 %@，用于打印 object。要打印数字，您可以使用 %d 之类的东西。 See complete documentation here.