如何将多个组件添加到 PickerView?

问题描述

这可能是一个简单的问题，但是如何将多个组件添加到 UIPickerView?我使用 NSMutableArray 填充一个组件，但我不知道如何填充其他组件.选择一行时，我还需要更改标签的值.提前致谢基兰

It may be a simple question but how do I add multiple components to a UIPickerView? I use NSMutableArray to populate one component but I dont know how to populate the others. I also need to change the value of a label when a row is selected. Thanks in advance Kieran

推荐答案

我认为你是初学者.以下是如何实现 nacho 正确指出的方法:

I take it that you are a beginner. Here's how to implement the methods nacho has rightly pointed out:

- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView {
    // return the number of components required
    return 2;
}

您可以使用其他 NSMutableArray 来填充组件.假设您有 2 个组件，每个组件使用不同的 NSMutableArray 即 array1 和 array2:

You can use other NSMutableArray's to populate the components. Assuming that you have 2 components, each using different NSMutableArray i.e. array1 and array2:

// Return row count for each of the components
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {
    if (component == 0) {
        return [array1 count];
    }
    else {
        return [array2 count];
    }
}

// Populate the rows of the Picker
- (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component {

    // Component 0 should load the array1 values, Component 1 will have the array2 values
    if (component == 0) {
        return [array1 objectAtIndex:row];
    }
    else if (component == 1) {
        return [array2 objectAtIndex:row];
    }
    return nil;
}

使用此代码更改 label 的文本，例如在 PickerView 中选择值时说 selectedValue:

Use this code to change the text of a label, say selectedValue when a value is selected in the PickerView:

- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
    selectedValue.text = [NSString stringWithFormat: @"%@, %@", [array1 objectAtIndex:[myPicker selectedRowInComponent:0]],[array2 objectAtIndex:[myPicker selectedRowInComponent:1]]];
}

...你很高兴:)

您可能还想查看 http://joshhighland.com/blog/2009/09/17/uipickerview-spinning-multiple-components/ 获取有关 pickerView 编程的宝贵提示.

You might also want to see http://joshhighland.com/blog/2009/09/17/uipickerview-spinning-multiple-components/ for valuable tips on pickerView programming.

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