如何在 iOS 7 下更改 UIPickerView 中文本的颜色？

Question

我知道pickerView:viewForRow:forComponent:reusingView 方法，但是当使用view 时，它传入reusingView: 如何更改它以使用不同的文本颜色？如果我使用view.backgroundColor = [UIColor whiteColor];，则不再显示任何视图。

Answer 1

委托方法中有一个更优雅的函数：

目标-C：

- (NSAttributedString *)pickerView:(UIPickerView *)pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    NSString *title = @"sample title";
    NSAttributedString *attString = 
        [[NSAttributedString alloc] initWithString:title attributes:@{NSForegroundColorAttributeName:[UIColor whiteColor]}];

    return attString;
}

如果您还想更改选择栏颜色，我发现我必须将 2 个单独的 UIViews 添加到包含 UIPickerView 的视图中，间隔 35 pts 以使选择器高度为 180。

斯威夫特 3：

func pickerView(_ pickerView: UIPickerView, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString? {

    let string = "myString"
    return NSAttributedString(string: string, attributes: [NSForegroundColorAttributeName:UIColor.white])
}

斯威夫特 4：

func pickerView(_ pickerView: UIPickerView, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString? {

    let string = "myString"
    return NSAttributedString(string: string, attributes: [NSAttributedStringKey.foregroundColor: UIColor.white])
}

Swift 4.2：

func pickerView(_ pickerView: UIPickerView, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString? {

    let string = "myString"
    return NSAttributedString(string: string, attributes: [NSAttributedString.Key.foregroundColor: UIColor.white])
}

使用该方法时请记住：您不需要实现titleForRowInComponent()，因为在使用attributedTitleForRow() 时它永远不会被调用。

Answer 2

原帖在这里：can I change the font color of the datePicker in iOS7?

- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
{
    UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, pickerView.frame.size.width, 44)];
    label.backgroundColor = [UIColor grayColor];
    label.textColor = [UIColor whiteColor];
    label.font = [UIFont fontWithName:@"HelveticaNeue-Bold" size:18];
    label.text = [NSString stringWithFormat:@" %d", row+1];
    return label;
}

// number Of Components
- (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView
{
    return 1;
}

// number Of Rows In Component
- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:   (NSInteger)component
{
    return 6;
}

Answer 3

1. 转到故事板
2. 选择 PickerView
3. 转到身份检查器（第三个选项卡）
4. 添加用户定义的运行时属性
5. KeyPath = textColor
6. 类型 = 颜色
7. 值 = [您选择的颜色]

Answer 4

在 Xamarin 中，重写 UIPickerModelView 方法 GetAttributedTitle

public override NSAttributedString GetAttributedTitle(UIPickerView picker, nint row, nint component)
{
    // change text white
    string title = GetTitle (picker, row, component); // get current text from UIPickerViewModel::GetTitle
    NSAttributedString ns = new NSAttributedString (title, null, UIColor.White); // null = font, use current font
    return ns;
}

Answer 5

对我有用

pickerView.setValue(UIColor.yellow, forKeyPath: "textColor")

Answer 6

我在使用两个组件的 pickerView 中遇到了同样的问题。我的解决方案类似于上面的一些修改。因为我使用了两个组件，所以需要从两个不同的数组中提取。

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

    UILabel *label = [[UILabel alloc] init];
    label.backgroundColor = [UIColor blueColor];
    label.textColor = [UIColor whiteColor];
    label.font = [UIFont fontWithName:@"HelveticaNeue-Bold" size:18];

    //WithFrame:CGRectMake(0, 0, pickerView.frame.size.width, 60)];

    if(component == 0)
    {
        label.text = [countryArray objectAtIndex:row];
    }
    else
    {
        label.text = [cityArray objectAtIndex:row];
    }
    return label;
}

Answer 7

Swift 4（更新已接受的答案）

extension MyViewController: UIPickerViewDelegate{
    }

    func pickerView(_ pickerView: UIPickerView, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString? {
        return NSAttributedString(string: "your-title-goes-here", attributes: [NSAttributedStringKey.foregroundColor: UIColor.white])
    }
}

Answer 8

- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view {
        UILabel* pickerLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, pickerView.frame.size.width, 37)];
        pickerLabel.text = @"text";
        pickerLabel.textColor = [UIColor redColor];
        return pickerLabel;
}