iphone - 弹出UIPickerView不显示

Question

我正在尝试实现一个弹出式 UIPickerView 来模拟单击 Safari 中的下拉字段时的行为，但到目前为止取得的成功有限。我发现:

Bottom pop-up UIPicker?

并尝试遵循这一点。到目前为止，我显示了 PopUpPickerView，但 UIPickerView 本身没有显示(我只看到 View 背景颜色显示)。

PopUpPickerViewController 有一个 nib 文件，因此当单击按钮时，会调用“更改”选择器，并且应该弹出 UIPickerView。目前，仅弹出 PopUpPickerView 的背景色。

如果您能提供任何帮助，我们将不胜感激。提前致谢!

我的代码如下:

PopUpPickerViewController.h

#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>
#import "PopUpPickerView.h"

#define UIColorMakeRGBA(nRed, nGreen, nBlue, nAlpha) [UIColor colorWithRed: (nRed)/255.0f green: (nGreen)/255.0f blue:(nBlue)/255.0f alpha:nAlpha]

@class PopUpPickerView;

@interface PopUpPickerViewController : UIViewController{
    NSArray *pickerData;
    PopUpPickerView *pickerView;
    UIPickerView *picker;
}

-(IBAction)change:(id)sender;
-(void)addSubviewToWindow:(UIView*) addView;

@property(nonatomic, retain) PopUpPickerView *pickerView;
@property(nonatomic, retain) NSArray *pickerData;
@property(nonatomic, retain) UIPickerView *picker;

@end

PopUpPickerViewController.m

#import "PopUpPickerViewController.h"
#import "PopUpPickerView.h"

@implementation PopUpPickerViewController

@synthesize pickerData, pickerView, picker;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];

     self.pickerView = [[PopUpPickerView alloc] initWithFrame:CGRectMake(0.0, 174.0, 320.0, 286.0)];
     self.picker = [[UIPickerView alloc] initWithFrame:CGRectMake(0.0, 70.0, 320.0, 216.0)];
     self.pickerView.picker = self.picker;
     //[self.picker addTarget:self action:@selector(pickerValueChanged:) forControlEvents:UIControlEventValueChanged];
     self.pickerView.parentViewController = self;
     [self.pickerView addSubview:self.picker];
 }

- (void)viewDidUnload
{
    [super viewDidUnload];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

-(IBAction)change:(id)sender{
    PopUpPickerView *pView = (PopUpPickerView*) pickerView;
    [pView animateDatePicker:YES];

}

-(void)addSubviewToWindow:(UIView*) addView{
     [self.view addSubview:addView];
}

@end

PopUpPickerView.h

#import <UIKit/UIKit.h>
#import "PopUpPickerViewController.h"

@class PopUpPickerViewController;

@interface PopUpPickerView : UIView<UIPickerViewDelegate, UIPickerViewDataSource>{
    UIPickerView *picker;
    PopUpPickerViewController *parentViewController;
    NSArray *pickerData;
}

-(void)animateDatePicker:(BOOL)show;

@property(nonatomic, retain) UIPickerView *picker;
@property(nonatomic, retain) NSArray *pickerData;
@property(nonatomic, retain) PopUpPickerViewController *parentViewController;

@end

PopUpPickerView.m

#import "PopUpPickerView.h"
#import "PopUpPickerViewController.h"

@implementation PopUpPickerView

@synthesize  picker, pickerData, parentViewController;

- (void)animateDatePicker:(BOOL)show {

    pickerData = [[NSArray alloc] initWithObjects:@"1", @"2", @"3", nil];

    self.picker.delegate = self;
    self.picker.dataSource = self;

    CGRect screenRect = self.frame;
    CGSize pickerSize = [self.picker sizeThatFits:CGSizeZero];

    CGRect startRect = CGRectMake(0.0,
                              screenRect.origin.y + screenRect.size.height,
                              pickerSize.width, pickerSize.height);

    CGRect pickerRect = CGRectMake(0.0,
                               screenRect.origin.y + screenRect.size.height,
                               pickerSize.width,
                              pickerSize.height);

    self.picker.frame = pickerRect;
    self.backgroundColor = UIColorMakeRGBA( 255, 125, 64, 0.7f - (int)show * 0.7f );

    if ( show ) {
        self.picker.frame = startRect;
        PopUpPickerViewController *controller = (PopUpPickerViewController*) self.parentViewController;
        [controller addSubviewToWindow:self];
    }

    [UIView beginAnimations:nil context:nil];
    [UIView setAnimationDuration:0.3f];
    [UIView setAnimationDelegate:self];

    self.backgroundColor = UIColorMakeRGBA( 255, 125, 64, 0.0f + (int)show * 0.7f );

    if ( show ) {
        self.picker.frame = pickerRect;

    } else {
        [UIView setAnimationDidStopSelector:@selector(slideDownDidStop)];
        self.picker.frame = startRect;
    }

    [UIView commitAnimations];  
}

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

-(NSInteger) pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
     return [pickerData count];
}

-(NSString*) pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component
{
    return [self.pickerData objectAtIndex:row];
}


 @end

Answer 1

事实证明，答案与 UIPickerView 放置的坐标有关。 UIPickerView 被放置在 PopUpPickerView 的底部，这意味着它位于屏幕外。调整坐标后一切正常。