UIPickerView显示错误的标题

Question

我的应用是带有多组分拾取轮的转换器。它用于转换一些变量。您可以看到的数字仅用于测试，没有什么重要的。

- (void)viewDidLoad
{
  [super viewDidLoad];
  _convertFrom = @[@"One (1)", @"Two (2)",
  @"Three (3)", @"Four (4)", @"Five (5)"];

  _convertRates = @[ @1.0f, @2.0f, @3.0f,
  @4.0f, @5.0f];

  _convertTo = @[@"One (1)", @"Two (2)",
  @"Three (3)", @"Four (4)", @"Five (5)"];

_convertRates = @[ @1.0f, @2.0f, @3.0f,
@4.0f, @5.0f];

}

我在iOS 6模拟器中测试应用时显示的数字有一个小问题。正如你在这里看到的那样：

http://imgur.com/q4uxm

当我尝试下列表时，数字会发生变化。但它们的价值却没有。 如果有人有时间检查出来并且可能找到解决方案，那将非常有用：）

这是在这种情况下可能很重要的其余代码：

#pragma mark -
#pragma mark PickerView DataSource

- (NSInteger)numberOfComponentsInPickerView:
 (UIPickerView *)pickerView
{
return 2;
}

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:    (NSInteger)component
{
if (component == 0)  {
    return [_convertFrom count];
}
return [_convertTo count];
}


- (NSString *) pickerView: (UIPickerView *)pickerView
          titleForRow:(NSInteger)row
         forComponent:(NSInteger)component
{
if (component == 0) {
    return [_convertFrom objectAtIndex:[pickerView selectedRowInComponent:0]];
}
return [_convertTo objectAtIndex:[pickerView selectedRowInComponent:1]];
}




#pragma mark -
#pragma mark PickerView Delegate
-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row
  inComponent:(NSInteger)component
{
    float convertFrom = [[_convertRates objectAtIndex:[pickerView  selectedRowInComponent:0]] floatValue];
float convertTo = [[_convertRates objectAtIndex:[pickerView selectedRowInComponent:1]] floatValue];
float input = [dollarText.text floatValue];
float to = convertTo;
float from = convertFrom;
float dollars = input;
float result = to * from * dollars;
float mtpaTilMtpaFloat = dollars * 1;
NSString *resultString = [[NSString alloc] initWithFormat:
                          @"result = %.2f *  %.2f = %.2f", from, to, result];
resultLabel.text = resultString;

NSString *mtpaTilmtpa = [[NSString alloc ] initWithFormat:
                           @" %.2f MTPA = %.2f MTPA", dollars, mtpaTilMtpaFloat];



if (from == 1, to == 1) { resultLabel.text = mtpaTilmtpa;
}

当然，告诉我是否需要显示更多代码以便您能够理解它。这是我第一次使用这个网站btw :)

Answer 1

不要使用selectedRowInComponent。您不想显示在所有行中选择的值。只需使用row

即可

- (NSString *) pickerView: (UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    if (component == 0) {
        return [_convertFrom objectAtIndex:row];
    }
    return [_convertTo objectAtIndex:row];
}