自定义UIPickerView包含三个组件，每个组件都在select指示器上显示标签

在我的应用程序中，我试图做一个包含三个组件（天，小时和分钟）的自定义UIPickerView 。 我已经制定了三个组件的自定义select器。 而现在我被困在如何将标签添加到select指示器，该指示器显示哪些组件是几天，几小时或几分钟。

我已经浏览了本网站上发布的每一个链接或问题，但是没有人帮助我。

我试图实现这样的形象

任何人都可以build议我怎么做到这一点？

Answer 1

多数民众赞成我是如何实现这一点….我已经使我的自定义PickerView的一些代码的帮助下，我发现…

在.h文件中：

 // LabeledPickerView.h // LabeledPickerView #import <UIKit/UIKit.h> @interface LabeledPickerView : UIPickerView { NSMutableDictionary *labels; } /** Adds the label for the given component. */ -(void)addLabel:(NSString *)labeltext forComponent:(NSUInteger)component forLongestString:(NSString *)longestString; @end 

和在.m文件中…

 // LabeledPickerView.m // LabeledPickerView #import "LabeledPickerView.h" @implementation LabeledPickerView /** loading programmatically */ - (id)initWithFrame:(CGRect)aRect { if (self = [super initWithFrame:aRect]) { labels = [[NSMutableDictionary alloc] initWithCapacity:3]; } return self; } /** loading from nib */ - (id)initWithCoder:(NSCoder *)coder { if (self = [super initWithCoder:coder]) { labels = [[NSMutableDictionary alloc] initWithCapacity:3]; } return self; } - (void) dealloc { [labels release]; [super dealloc]; } #pragma mark Labels // Add labelText to our array but also add what will be the longest label we will use in updateLabel // If you do not plan to update label then the longestString should be the same as the labelText // This way we can initially size our label to the longest width and we get the same effect Apple uses -(void)addLabel:(NSString *)labeltext forComponent:(NSUInteger)component forLongestString:(NSString *)longestString { [labels setObject:labeltext forKey:[NSNumber numberWithInt:component]]; NSString *keyName = [NSString stringWithFormat:@"%@_%@", @"longestString", [NSNumber numberWithInt:component]]; if(!longestString) { longestString = labeltext; } [labels setObject:longestString forKey:keyName]; } // - (void) updateLabel:(NSString *)labeltext forComponent:(NSUInteger)component { UILabel *theLabel = (UILabel*)[self viewWithTag:component + 1]; // Update label if it doesn’t match current label if (![theLabel.text isEqualToString:labeltext]) { NSString *keyName = [NSString stringWithFormat:@"%@_%@", @"longestString", [NSNumber numberWithInt:component]]; NSString *longestString = [labels objectForKey:keyName]; // Update label array with our new string value [self addLabel:labeltext forComponent:component forLongestString:longestString]; // change label during fade out/in [UIView beginAnimations:nil context:NULL]; [UIView setAnimationDuration:0.75]; [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut]; theLabel.alpha = 0.00; theLabel.text = labeltext; theLabel.alpha = 1.00; [UIView commitAnimations]; } } /** Adds the labels to the view, below the selection indicator glass-thingy. The labels are aligned to the right side of the wheel. The delegate is responsible for providing enough width for both the value and the label. */ - (void)didMoveToWindow { // exit if view is removed from the window or there are no labels. if (!self.window || [labels count] == 0) return; UIFont *labelfont = [UIFont boldSystemFontOfSize:15]; // find the width of all the wheels combined CGFloat widthofwheels = 0; for (int i=0; i<self.numberOfComponents; i++) { widthofwheels += [self rowSizeForComponent:i].width; } // find the left side of the first wheel. // seems like a misnomer, but that will soon be corrected. CGFloat rightsideofwheel = (self.frame.size.width - widthofwheels) / 2; // cycle through all wheels for (int component=0; component<self.numberOfComponents; component++) { // find the right side of the wheel rightsideofwheel += [self rowSizeForComponent:component].width; // get the text for the label. // move on to the next if there is no label for this wheel. NSString *text = [labels objectForKey:[NSNumber numberWithInt:component]]; if (text) { // set up the frame for the label using our longestString length NSString *keyName = [NSString stringWithFormat:@"%@_%@", [NSString stringWithString:@"longestString"], [NSNumber numberWithInt:component]]; NSString *longestString = [labels objectForKey:keyName]; CGRect frame; frame.size = [longestString sizeWithFont:labelfont]; // center it vertically frame.origin.y = (self.frame.size.height / 2) - (frame.size.height / 2) - 0.5; // align it to the right side of the wheel, with a margin. // use a smaller margin for the rightmost wheel. frame.origin.x = rightsideofwheel - frame.size.width - (component == self.numberOfComponents - 1 ? 5 : 7); // set up the label. If label already exists, just get a reference to it BOOL addlabelView = NO; UILabel *label = (UILabel*)[self viewWithTag:component + 1]; if(!label) { label = [[[UILabel alloc] initWithFrame:frame] autorelease]; addlabelView = YES; } label.text = text; label.font = labelfont; label.backgroundColor = [UIColor clearColor]; label.shadowColor = [UIColor whiteColor]; label.shadowOffset = CGSizeMake(0,1); // Tag cannot be 0 so just increment component number to esnure we get a positive // NB update/remove Label methods are aware of this incrementation! label.tag = component + 1; if(addlabelView) { /* and now for the tricky bit: adding the label to the view. kind of a hack to be honest, might stop working if Apple decides to change the inner workings of the UIPickerView. */ if (self.showsSelectionIndicator) { // if this is the last wheel, add label as the third view from the top if (component==self.numberOfComponents-1) [self insertSubview:label atIndex:[self.subviews count]-3]; // otherwise add label as the 5th, 10th, 15th etc view from the top else [self insertSubview:label aboveSubview:[self.subviews objectAtIndex:5*(component+1)]]; } else // there is no selection indicator, so just add it to the top [self addSubview:label]; } if ([self.delegate respondsToSelector:@selector(pickerView:didSelectRow:inComponent:)]) [self.delegate pickerView:self didSelectRow:[self selectedRowInComponent:component] inComponent:component]; } } } 

并调用这个addLabel：方法与标签文本和组件标签，多数民众赞成在..！

Answer 2

下载自定义UIPickerView控件的源代码。

自定义UiPickerView。

希望它帮助你:)