UIPicker标签与输出不同

Question

I have a UIPicker populated with an NSarray. This sends the row selected to a text field. I would like to know how to change the name of the rows in my picker. Sorry if its not clear im having difficulty explaining what I mean clearly.

 - (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    arrStatus = [[NSArray alloc] initWithObjects:@"A", @"B", @"C", @"D", nil];
}

-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
    //One column
    return 1;
}

-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent: (NSInteger)component
{
    //set number of rows
    return arrStatus.count;
}

-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    //set item per row
    return [arrStatus objectAtIndex:row];
}

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
    NSInteger selectedRow = [result selectedRowInComponent:0];
    text1.text = [arrStatus objectAtIndex:selectedRow];
}

Answer 1

Here is an example of what I think is close to what you want. If you had 2 arrays, one with the country names, and one with the populations (in the same order), you could use the following code to create an array of dictionaries that would contain both values (you could actually use the 2 arrays directly, but that would require that you keep them in sync if you make any changes. It would be better to do it like below):

NSMutableArray *arrStatus = [NSMutableArray array];
    NSArray *nameArray = [NSArray arrayWithObjects:@"Albania",@"Brazil",@"Columbia", nil];
    NSArray *popArray = [NSArray arrayWithObjects:@10.3,@200,@50, nil];
    NSMutableDictionary *dict = [NSMutableDictionary dictionary];
    for (int i=0; i<nameArray.count; i++) {
        [dict setValue:[nameArray objectAtIndex:i] forKey:@"countryName"];
        [dict setValue:[popArray objectAtIndex:i] forKey:@"poulation"];
        [arrStatus addObject:[dict copy]];
    }

Now, in your picker methods, you could do this:

-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    //set item per row
    return [[arrStatus objectAtIndex:row] valueForKey:@"countryNames"];
}

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    text1.text = [arrStatus objectAtIndex:row] valueForKey:@"population"];
}

This would put the population numbers in the text field, and the country names in the picker. Notice that I changed the way I got the value in the didSelectRow method -- no need to define selectedRow, the row argument passed into the method has that value already.

The way I put the population numbers in the popArray will only work in OS X 10.8 I think, I'm not sure whether it works in iOS, or if so, in what version. You would have to replace @10.3, for example, with [NSNumber numberWithFloat:10.3] in earlier versions.