Question

是否有人知道如何制作依赖UIPickerView。例如，当我选择组件1的第2行时，组件2的标题会发生变化吗？

我在互联网上看到没有真正的答案，我尝试使用if和switch语句，但它们只是崩溃。

Answer 1

这取决于您将如何保存数据。例如，如果您将数组作为字典键的值，并且该字典具有不同的此类键，则第一列将是键，而在选择一列时，您将在另一列中显示该数组（组件））。 - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView方法应返回2。在 - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component 方法，您需要在组件1的字典中给出键的数量，以及当前所选键的数组的计数。例如

if(component==0) return [[DICTIONARY allKeys] count];
else return [[DICTIONARY objectForKey:@"SELECTED_KEY"] count];

然后，

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

    selectedIndex = [pickerView selectedRowInComponent:0];
    if (component == 1 && !(selectedIndex < 0)) {
        [pickerView reloadComponent:2];

        [pickerView selectRow:0 inComponent:2 animated:YES];
    }

}

和

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

    UILabel *pickerRow = (view != nil) ? view : [[[UILabel alloc] initWithFrame:CGRectMake(5, 0, 115, 60)] autorelease];
    pickerRow.font = [UIFont boldSystemFontOfSize:14];
    pickerRow.textAlignment = UITextAlignmentLeft;
    pickerRow.backgroundColor = [UIColor clearColor];
    pickerRow.textColor = [UIColor blackColor];
    pickerRow.numberOfLines = 0;
    if (component == 0) {

        pickerRow.text = @"DICTIONARY_ROW'th_KEY";
    }
    else {

        pickerRow.text = [[dictionary objectForKey:@"SELECTED_KEY"] objectAtIndex:row];

    }
    return pickerRow;
}

Answer 2

我确信这可以使用委托方法pickerView：didSelectRow：inComponent：和reloadComponents的组合来完成。

Answer 3

希望这有帮助，我有类似的情况，我的要求是当我在组件中选择国家/地区名称时，应该在第二个组件中加载该国家/地区的城市。所以我做的是，我有2个pickerview并排，当用户在国家选择器中选择一行时，我重新启动了第二个选择器并提供了适当的数据。

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

    if (pickerView == countryPickerView)    
    {

        if(PickerViewCity)
        {
            [PickerViewCity removeFromSuperview];
            [PickerViewCity release];
            PickerViewCity=nil;
        }


        PickerViewCity = [[UIPickerView alloc] initWithFrame:CGRectMake(160, 38, 320, 240)];
        PickerViewArrayCity=[[countryPickerViewArray objectAtIndex:[pickerView selectedRowInComponent:0]]objectForKey:@"nodeChildArray"];
        //NSLog(@"%@",PickerViewArrayCity);
        PickerViewCity.showsSelectionIndicator = YES;   // note this is default to NO
        PickerViewCity.delegate = self;
        PickerViewCity.dataSource = self;
        CGAffineTransform s20 = CGAffineTransformMakeScale(0.5, 0.58);
        CGAffineTransform t21 = CGAffineTransformMakeTranslation(-80,-50);
        PickerViewCity.transform = CGAffineTransformConcat(s20, t21);
        PickerViewCity.layer.masksToBounds = YES;
        [someview addSubview:PickerViewCity];       
    }


    if (pickerView == PickerViewCity)   
    {


    }   
}

Answer 4

我认为，您希望在更改另一个组件时更改一个组件的相应项。这可能是一个更好的解决方案。

代码：

- (void)pickerView:(UIPickerView *)pickerView
      didSelectRow:(NSInteger)row
       inComponent:(NSInteger)component {
    if (component == 0) {

        //Here First Part of the Pickerview is represented using 0.
        // dependentPicker is the Pickerview outlet

        [dependentPicker selectRow:row inComponent:1 animated:YES];
        [dependentPicker reloadComponent:1];
    }
    else
    {
        [dependentPicker selectRow:row inComponent:0 animated:YES];
        [dependentPicker reloadComponent:1];
    }
}

注意：使用此代码时，组件值必须由两个NSArray保持，并且两个数组中相应依赖值的顺序必须相同。

Answer 5

你需要为第一个组件的每一行设置条件（索引为0）并打开一个开关来选择每个索引，我做了它并为我工作：

on ... titleForRow:(NSinteger)row forComponent(NSInteger)component

{
    if (component == 0)  // this is first component from left to right
        return [arrayForFirstComponent objectAtIndex:row];
    if (component == 1)  // this is second component from left to right
        switch([pickerIBOutletAsYouNamedIt selectedRowInComponent:0])  // here you set content of component two depending on which row is selected from component 1
        {
             case 0:            // remember index starts at 0
                 return [arrayForComponent2ForRow1inComponent1 objectAtIndex:row];
                 break;
             //... and so on for each row in the component 1 (with index 0)
        }
}

记住：你也必须这样做 - ...... numberOfRowsInComponent:(NSInteger)component 与 - ...... didSelectRow:(NSInteger)row inComponent:(NSInteger)component 在他的最后一个中，在组件0中选择行调用[pikcerIBOutlet reloadComponent:1]

依赖UIPickerView

5 个答案: