ios - 如何格式化 iOS 7 UIPickerView 以仅显示 3 个选择？ IE。主动选择上面一个和下面一个？

Question

我想格式化 iOS 7 UIPickerView 以仅显示三个选项。 IE。所选选项上方一个，下方一个。我还想将文本格式设置为小于默认值。我如何实现这一目标？

Answer 1

实现这些委托(delegate)方法将为您提供一个 3 行的选择器 View ，并让您自定义字体、颜色等...

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

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

        UILabel *pickerRowLabel = (UILabel *)view;

        if (pickerRowLabel == nil) {
            CGRect frame = //YOUR PICKERVIEW FRAME. HEIGHT IS 44 by default.
            pickerRowLabel = [[UILabel alloc] initWithFrame:frame];
           //FORMAT THE FONT FOR THE LABEL AS YOU LIKE
            pickerRowLabel.backgroundColor = [UIColor clearColor];
            pickerRowLabel.userInteractionEnabled = YES;
        }

        pickerRowLabel.text = //YOUR TEXT, MOST LIKELY FROM AN ARRAY ... ?

        return pickerRowLabel;
    }

    - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component {

        return 3; //MOST LIKELY YOUR ARRAY OF OBJECTS COUNT
    }