问题
I'm trying to implement the answer to this SO question. The problem is: -[drawTextInRect] is apparently not called, and setting the shadow in -[drawRect] doesn't make the UITextField's text shadowed.
Another weird thing is that even if my subclass implementations of -[drawTextInRect] and -[drawRect] are completely empty (not even a call to super), the textfield's text is drawn.
回答1:
This is a bug in the UITextField API documentation. The documentation indicates that overriding drawTextInRect: can be used to customize behaviour. This is not the case.
In fact, drawTextInRect: will never be called on an UITextField (drawPlaceholderInRect: will be called neither by the way).
See also http://discussions.apple.com/thread.jspa?threadID=1727596.
Overriding the method on UILabel works though.
回答2:
I guess the method you are looking for is:
- (CGRect)textRectForBounds:(CGRect)bounds
or possibly
- (CGRect)editingRectForBounds:(CGRect)bounds
回答3:
I note that -[drawTextInRect] is called once when the UITextField loses focus. Not what I wanted.
回答4:
UITextField does not respond to a - drawTextInRect: message. The code on the page you reference subclasses a UILabel not a UITextField, which is why it didn't work for you.
回答5:
If you don't call super, the compiler might be removing the method during optimization of your code. Effectively meaning that UILabel's implementation is getting called.
Update: If you are using a nib to create the textfield, be sure you have set the class of the textfield in the nib to your custom subclass, otherwise your custom code will not be called.
来源：https://stackoverflow.com/questions/1920783/drawtextinrect-on-uitextfield-not-called