好吧,也许我错过了一些非常简单的事情,如果是这样的话我会道歉,但是,我已经搜索了标题的每一个排列并且没有找到!所以这就是我想要做的事情:当选择该行时,将我正在使用的标签的背景颜色更改为2组件选择器视图中的行视图。所以我认为这会奏效:
if (row == [pickerview selectedRowForComponent])
viewlabel.backgroundColor = redcolor;
但这不起作用。它似乎随意选择要着色的行,有时甚至会给出错误的访问错误。我试过所有不同的条款都没有效果!任何建议将不胜感激!!
这是完整的方法:
- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
{
if (component == kNumberComponent) {
#define PICKER_LABEL_FONT_SIZE 24
#define PICKER_LABEL_ALPHA 1.0
// UIFont *font = [UIFont boldSystemFontOfSize:PICKER_LABEL_FONT_SIZE];
UIFont *font = [ UIFont fontWithName:@"AppleGothic" size:24];
UILabel *carsLabel =[ [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 75, 50) ]autorelease];
//[picker selectRow:row inComponent:component animated:YES];
NSString *pickerText = [self.numbers objectAtIndex:(int)row];
carsLabel.text = pickerText;
carsLabel.textAlignment = UITextAlignmentCenter;
NSLog(@"carsLabel = %@",carsLabel.text);
//carsLabel.text = @"maybe because the string isn't long enough";
carsLabel.textColor = [UIColor blackColor];
carsLabel.font = font;
carsLabel.opaque = YES;
[view addSubview:carsLabel];
return carsLabel;
} else {
UIFont *font = [ UIFont fontWithName:@"AppleGothic" size:18];
UILabel *carsLabel = [[[UILabel alloc] initWithFrame:CGRectMake(0, 0, 225, 50)] autorelease];
id fact = [self.facts objectAtIndex:(int)row];
NSString *pickerText = @"Dictionary Entry";
if ( [fact isKindOfClass:[NSString class]]) {
pickerText = [self.facts objectAtIndex:(int)row];
}
carsLabel.text = pickerText;
carsLabel.textAlignment = UITextAlignmentCenter;
NSLog(@"carsLabel = %@",carsLabel.text);
//carsLabel.text = @"maybe because the string isn't long enough";
carsLabel.textColor = [UIColor blackColor];
carsLabel.font = font;
if ( row == 0) {
carsLabel.backgroundColor = [UIColor redColor];
}
//carsLabel.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"blackboard.png"]];;
carsLabel.opaque = YES;
[view addSubview:carsLabel];
return carsLabel;
}
return nil;
}
通常,我使用这种方法:
我使用自定义视图来显示行项目
-(UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
{
UILabel *label = (id)view;
if (!label)
{
label= [[UILabel alloc] initWithFrame:CGRectMake(0.0f, 0.0f, [pickerView rowSizeForComponent:component].width, [pickerView rowSizeForComponent:component].height)];
label.textAlignment = NSTextAlignmentCenter;
label.textColor = [UIColor whiteColor];
label.text = _arrayStringPicker[row];
}
return label;
我改变选择的行的颜色:
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component
{
UILabel *labelSelected = (UILabel*)[pickerView viewForRow:row forComponent:component];
[labelSelected setTextColor:[UIColor redColor]];
}
Swift版本的@ alessandro-pirovano回答
func pickerView(_ pickerView: UIPickerView, viewForRow row: Int, forComponent component: Int, reusing view: UIView?) -> UIView {
let rowSize = pickerView.rowSize(forComponent: component)
let width = rowSize.width
let height = rowSize.height
let frame = CGRect(x: 0, y: 0, width: width, height: height)
let label = UILabel(frame: frame)
label.textAlignment = .center
label.text = rows[row]
return label
}
func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
guard let label = pickerView.view(forRow: row, forComponent: component) as? UILabel else {
return
}
label.backgroundColor = .orange
}
viewForPicker的正确格式是:
- (UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view
{
UILabel *label = (UILabel*) view;
if (label == nil)
{
label = [[UILabel alloc] init];
}
[label setText:@"Whatever"];
// This part just colorizes everything, since you asked about that.
[label setTextColor:[UIColor whiteColor]];
[label setBackgroundColor:[UIColor blackColor]];
CGSize rowSize = [pickerView rowSizeForComponent:component];
CGRect labelRect = CGRectMake (0, 0, rowSize.width, rowSize.height);
[label setFrame:labelRect];
return label;
}
上面代码的问题是:它使标签着色,而不是选择器本身。因此,当您滚动到一端或另一端时,会有一个空白点,您可以看到白色背景。设置[myPicker setBackgroundColor ...]并不能达到人们所希望的效果。
//我们想要的帧的CGRectMake值
UIPickerView *myPickerView = [[UIPickerView alloc] initWithFrame:CGRectMake(0,0, self.view.bounds.size.width, self.view.bounds.size.height)];
// add the UIPickerView to your viewcontroller [mainView addSubview:myPickerView];
// set the selectionindicator to none myPickerView.showsSelectionIndicator = NO;
//定义我们想要使用的图像
UIImage *selectorImage = [UIImage imageNamed:@"selectionIndicator.png"];
UIView *customSelector = [[UIImageView alloc] initWithImage:selectorImage];
//将x和y值设置为UIPickerView上要放置图像的位置
//将宽度和高度值设置为图像的宽度和高度
customSelector.frame = CGRectMake(10,(myPickerView.bounds.size.height / 2) + 16, self.view.bounds.size.width – 10, 47);
//也将自定义selectionIndicator添加到同一个viewcontroller
[mainView addSubview:customSelector];
解决了!声明2个实例变量:selectedView和oldView。然后以下代码可以解决问题:
if (self.oldView != nil)
self.oldView.backgroundColor = [UIColor clearColor];
self.selectedView = [picker viewForRow:row forComponent:kNumberComponent];
self.selectedView.backgroundColor = [UIColor redColor];
[self.selectedView setNeedsDisplay];
self.oldView = self.selectedView;
快速实施
extension PickerViewController: UIPickerViewDelegate {
func pickerView(pickerView: UIPickerView, attributedTitleForRow row: Int, forComponent component: Int) -> NSAttributedString? {
var color: UIColor!
if pickerView.selectedRowInComponent(component) == row {
color = UIColor.redColor()
} else {
color = UIColor.blackColor()
}
let attributes: [String: AnyObject] = [
NSForegroundColorAttributeName: color,
NSFontAttributeName: UIFont.systemFontOfSize(15)
]
return NSAttributedString(string: rows[row], attributes: attributes)
}
func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
//this will trigger attributedTitleForRow-method to be called
pickerView.reloadAllComponents()
}
}
调用UIPickerView
实例的-viewForRow:forComponent:
方法来获取UIView *
对象。然后设置该视图的背景UIColor
。
目前还不清楚您将上述代码放在何处。是在-pickerView:viewForRow:forComponent:reusingView:
?这应该是它应该的地方。您确定要维护指向该特定视图的标签的指针吗?你崩溃的事实暗示你可能不是。更大的代码块,包括您放置它的位置,将会很有帮助。
这对我有用:
UIView
添加为UIPickerView
的子视图UIPickerView
输入的Y并且具有相同的宽度pickerView(_ pickerView: UIPickerView, rowHeightForComponent component: Int) -> CGFloat
返回的高度*其他解决方案(对于行的行或属性字符串的自定义视图)在快速滚动时是错误的。
UIPickerView有委托为行和组件设置NSAttributeString我们可以设置属性颜色,如下所示:
- (NSAttributedString *)pickerView:(UIPickerView *)pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component {
NSDictionary *attrs = @{NSForegroundColorAttributeName : [UIColor redColor]};
NSString *title = @"title"
return [[NSAttributedString alloc] initWithString:title attributes:attrs];
}