How can I save a second row of UIPickerView to NSUserDefaults?

问题

I have pickerView with two rows and I need to save position of both to NSUserDefaults. I have successful saved first row with this code:

- (void)pickerView:(UIPickerView *)thePickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {    
    NSInteger selectedRow = [thePickerView selectedRowInComponent:0];

    [[NSUserDefaults standardUserDefaults] setInteger:selectedRow forKey:@"picker"];
}

And I don't get how to add a second one.

With this code I bring back the position:

-(void)viewWillAppear: (BOOL) animated {
    NSUserDefaults *pickerViewSelectionDefaults = [NSUserDefaults standardUserDefaults];
[picker selectRow:[pickerViewSelectionDefaults integerForKey:@"picker"] inComponent:0 animated:YES];
[picker selectRow:[pickerViewSelectionDefaults integerForKey:@"picker"] inComponent:1 animated:YES];
}

回答1:

Try this:

- (void)pickerView:(UIPickerView *)thePickerView didSelectRow:(NSInteger)row
             inComponent:(NSInteger)component {    
    NSInteger selectedRow = [thePickerView selectedRowInComponent:component];
    NSString *key = [NSString stringWithFormat:@"picker%d", component];

    [[NSUserDefaults standardUserDefaults] setInteger:selectedRow forKey:key];
}

and this

-(void)viewWillAppear: (BOOL) animated {
    NSUserDefaults *pickerViewSelectionDefaults = [NSUserDefaults standardUserDefaults];
    [picker selectRow:[pickerViewSelectionDefaults integerForKey:@"picker0"] 
        inComponent:0 animated:YES];
    [picker selectRow:[pickerViewSelectionDefaults integerForKey:@"picker1"] 
        inComponent:1 animated:YES];
}

回答2:

Add them with separate keys.

- (void)pickerView:(UIPickerView *)thePickerView didSelectRow:(NSInteger)row inComponent:   (NSInteger)component {    
NSInteger selectedRow = [thePickerView selectedRowInComponent:0];

[[NSUserDefaults standardUserDefaults] setInteger:selectedRow forKey:@"pickerRow1"];
[[NSUserDefaults standardUserDefaults] setInteger:selectedRow forKey:@"pickerRow2"];
}

来源：https://stackoverflow.com/questions/6034276/how-can-i-save-a-second-row-of-uipickerview-to-nsuserdefaults