UIPickerView 的 selectedRowInComponent 仅在旋转且未选中时返回随机行。怎么了？

Posted 2023-02-24

【中文标题】UIPickerView 的 selectedRowInComponent 仅在旋转且未选中时返回随机行。怎么了？

【英文标题】：selectedRowInComponent for UIPickerView is returning random rows only when spun and not selected. What is happening?

【发布时间】：2013-03-15 02:26:16

【问题描述】：

我有一个双选择器和两个 NSInteger 变量，用于更新选择器的每个组件所在的行。在 iPhone 模拟器中（我没有在实际的 iPhone 上测试过），如果我选择行（即单击下方或上方），数字很好，但是当我旋转时，我收到的行号通常与实际相差几个。这是我所拥有的：

- (UIView *)pickerView:(UIPickerView *)pickerView
        viewForRow:(NSInteger)row
      forComponent:(NSInteger)component reusingView:(UIView *)view 

if (component == kSuitComponent) 
    UIImage *image = self.suitImages[row];
    UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
    [self theSuitRow];
    return imageView;

else 
    NSString *text = self.cardNumber[row];
    UILabel *label = [[UILabel alloc] init];
    [self getCardRow];
    label.text = text;
    return label;


 -(void) getCardRow 
    cardRow = [_doublePicker selectedRowInComponent:kCardNumberComponent];

-(void) theSuitRow 
suitRow = [_doublePicker selectedRowInComponent:kSuitComponent];

【问题讨论】：

viewForRow:forComponent: 用于用视图填充行，并被多次调用——您不应该使用它来获取选定的行。您是否有理由不使用 pickerView:didSelectRow:inComponent:

【参考方案1】：

应该是：

- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view 

    if (component == kSuitComponent) 
        UIImage *image = self.suitImages[row];
        UIImageView *imageView = [[UIImageView alloc] initWithImage:image];
        return imageView;
    
    else 
        NSString *text = self.cardNumber[row];
        UILabel *label = [[UILabel alloc] init];
        label.text = text;
        return label;
    


- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component 
    if (component == kCardNumberComponent) 
        cardRow = row;
     else 
        suitRow = row;