关于 iOS键盘弹出警告"Can't find keyplane......"

一点击UITextField，logo显示区就打印如下：

Can't find keyplane that supports type 4 for keyboard iPhone-PortraitChoco-NumberPad; using 1336863583__PortraitChoco__iPhone-Simple-Pad__Default_

_我对UITextField的代码如下：

rect = CGRectMake(xx + side * 2.0, yy, ww - side * 2.2, hh);
phoneTextField = [[UITextField alloc] initWithFrame:rect];
CGFloat fontSize = hh * 0.45;
UIFont *font = [UIFont systemFontOfSize:fontSize];
phoneTextField.font = font;
phoneTextField.placeholder = @"输入手机号码";
if (kIsiPad) {
phoneTextField.returnKeyType = UIReturnKeyNext;
}
phoneTextField.keyboardType = UIKeyboardTypeNumberPad;
phoneTextField.delegate = self;
phoneTextField.clearButtonMode = UITextFieldViewModeWhileEditing;
[self addSubview:phoneTextField];