UIPicker首先出現黑色

Question

我有以下代碼來繪製自定義選取器。不幸的是，當第一次繪製視圖是黑色的。只有當我觸摸它時纔會出現。

我該如何解決這個問題？

這裏是UIView的相關代碼：

- (void)drawRect:(CGRect)rect 
{ 
    [self createPicker]; 
    [self addSubview:dPicker]; 
//[dPicker reloadComponent:1]; 
} 

-(void) createPicker 
{ 
    dPicker = [[UIPickerView alloc] initWithFrame:CGRectZero]; 
    CGSize pickerSize = [dPicker sizeThatFits:CGSizeZero]; 
    dPicker.frame = [self pickerFrameWithSize:pickerSize]; 
    dPicker.delegate=self; 
    dPicker.showsSelectionIndicator = YES; 
    dPicker.hidden=NO; 
} 


- (CGRect)pickerFrameWithSize:(CGSize)size 
{ 
    CGRect screenRect = [[UIScreen mainScreen] applicationFrame]; 
    CGRect pickerRect = CGRectMake(0.0, 
           screenRect.size.height - 44.0 - size.height, 
           size.width, 
           size.height); 
    return pickerRect; 
} 

Answer 1

固定它。從UIViewController調用子視圖而不是UIView