ios - 当我点击 UITextField 时如何显示 UIPickerView？

Question

我从互联网上找到了很多示例代码，但也不起作用....任何人都可以告诉我下面的代码有什么问题？多谢。紧急求救

//我的storeboard屏幕
http://imageupload.org/en/file/209300/03.jpg.html

//This is PickerViewTest.h

@interface InputRound : UIViewController<UITextFieldDelegate>
{
    UIPickerView *pvPickerTest;
    NSMutableArray *aryMaster;
}

@property (nonatomic, retain) IBOutlet UIPickerView *pvPickerTest; 
@property (nonatomic, retain) NSMutableArray *aryMaster;

@end


//This is PickerViewTest.m

@interface InputRound ()

@end

@implementation PickerViewTest

@synthesize pvPickerTest, aryMaster;

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

-(void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    aryMaster = [[NSMutableArray alloc] init];

    [aryMaster addObject:@"User01"];
    [aryMaster addObject:@"User02"];
    [aryMaster addObject:@"User03"];    
}

-(NSInteger)numberOfComponentsInPickerView:(NSInteger)component
{
    return 1;
}

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

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

-(void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
}

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

-(BOOL)textFieldShouldBeginEditing:(UITextField *)textField
{
    // Show UIPickerView
    pvPickerTest.frame = CGRectMake(0, 500, pvPickerTest.frame.size.width,     pvPickerTest.frame.size.height);

    [UIView beginAnimations:nil context:NULL];
    [UIView setAnimationDuration:.50];
    [UIView setAnimationDelegate:self];

    pvPickerTest.frame = CGRectMake(0, 200, pvPickerTest.frame.size.width, pvPickerTest.frame.size.height);
    [self.view addSubview:pvPickerTest];
    [UIView commitAnimations];    
    return NO;
}

@end

Answer 1

不要尝试通过滚动您自己的外观动画来模仿内置动画来重新发明轮子。将选择器 View 设置为文本字段的输入 View ，系统将为您制作动画:

textField.inputView = pickerView;

当您开始编辑文本字段时，选择器会在屏幕上为您动画显示。看我的回答here有关更多详细信息，包括在顶部添加带有“完成”按钮的工具栏。