Default UIPickerView height
How can I programatically obtain the default height of an UIPickerView instance, in accordance to the resolution and orientation of the device that the app is currently running on?
I would like not to use a hardcoded value for this parameter, in the event that new devices will support different screen resolutions and thus will determine this component to have a different default size.
Answer
The warning that André saw doesn't seem to happen anymore (XCode 4.2; iOS SDK 5.0). If you create it with initWithFrame and give it a height of zero, you can then read back it's height from the frame.height property:
uiPickerView = [[UIPickerView alloc] initWithFrame:CGRectMake(0, 77, 320, 0)];
DLog(@"uiPickerView=%@",uiPickerView);
gives:
uiPickerView=<UIPickerView: 0x9a28c40; frame = (0 77; 320 216); layer = <CALayer: 0x9a28d00>>
So 216 is the default height.
I couldn't find a definition for this in the headers, so reading it back seems to be the safest way.
It is possible to set a frame with a non-zero height, but Apple say don't do that, and it seems to cause rendering problems.