使用多个UIPickerView

Question

我决定使用UIPickerView来模拟一种下拉菜单。我的问题是，我想使用多个UIPickerView。如何设置第二个UIPickerView？添加新的UIViewController？或者它是如何工作的？添加第二个跨度是不够的，我还需要3个UIPickerViews。提前感谢:)

代码：

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

    -(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
        return [pickerarray count];
    }

    -(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {
        return [pickerarray objectAtIndex:row];
    }

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

- (void)viewDidLoad {

pickerarray = [[NSMutableArray alloc] init];
[pickerarray addObject:@"Hamburg"];
[pickerarray addObject:@"Berlin"];
[pickerarray addObject:@"München"];
[pickerarray addObject:@"Bonn"];

pickerarray2 = [[NSMutableArray alloc] init];
[pickerarray2 addObject:@"Hambburg"];
[pickerarray2 addObject:@"Berelin"];
[pickerarray2 addObject:@"Müneechen"];
[pickerarray2 addObject:@"Boneen"];
}

Answer 1

1. 将它们全部添加到视图中。
2. 将它们设置为隐藏。
3. 为它们中的每一个都设置了唯一的标记。
4. 添加了一些按钮，这些按钮“显示根据选取器视图标记管理值的委托方法。

代码更新：

// put this before view controllers @implementation
enum {
  MyFirstPickerViewTag = 1,
  MySecondPickerViewTag
} MyPickerViewTags; // fix for warning

// assign tags 1 and 2 respectively to your picker views in IB
// here's one of delegate methods

-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
    switch(pickerView.tag) {
        case MyFirstPickerViewTag: {
            return 2;
        }
        case MySecondPickerViewTag: {
            return 3;
        }
    }
    return 1; //  component by default
}