更新UIPickerView行数

-- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component

{

return ([sectionNamesArray count] + 1);

}

问题是我将这个pickerView添加到titleView中导航条的中心。如果我尝试取消UIPickerView并重新分配它以希望再次调用委托,那么PickerView将显示在导航栏的左侧,而不是中间。我猜可能是界面生成器的设置把它放在了中间。。。?

这是密码:

-(void) setupPickerView{
myPickerView = nil;
myPickerView = [[UIPickerView alloc] init];
myPickerView.backgroundColor = [UIColor clearColor];
myPickerView.delegate = self;
myPickerView.dataSource = self;
myPickerView.showsSelectionIndicator = YES;
[self.navigationController.navigationBar setBackgroundView:myPickerView];

CGSize pickerSize = [myPickerView sizeThatFits:CGSizeZero];
UIView *pickerTransformView = [[UIView alloc] initWithFrame:CGRectMake(-40.0, -43.0, pickerSize.width, pickerSize.height)];
pickerTransformView.transform = CGAffineTransformMakeScale(.55f, .55f);

[pickerTransformView addSubview:myPickerView];
[self.navigationController.navigationBar setBackgroundView:pickerTransformView];

}