UITextField 使用时候如果两个手指同时点击输入框，出现焦点消失

m_idEdit = [[UITextFieldEx alloc] initWithFrame:CGRectMake(58.0f, 152.0f, 210, 28.0f)];
m_idEdit.m_bAdjustClearBtn = YES;
m_idEdit.backgroundColor = [UIColor colorWithRed:1.0f green:1.0f blue:1.0f alpha:0.0f];
[m_idEdit setDelegate:self];
        
m_idEdit.font = [UIFont systemFontOfSize:18.0];
m_idEdit.placeholder = @"XXX";
m_idEdit.clearButtonMode = UITextFieldViewModeWhileEditing;
m_idEdit.autocorrectionType = UITextAutocorrectionTypeNo;    
m_idEdit.keyboardType = UIKeyboardTypeNumberPad ;
m_idEdit.borderStyle = UITextBorderStyleNone;
m_idEdit.text = @"";
        
[self addSubview:m_idEdit];
[m_idEdit setHidden:NO];