防止输入时键盘覆盖掉输入框

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardwasChange:) name:UIKeyboardWillChangeFrameNotification object:nil];

- (void)keyboardwasChange:(NSNotification *)info {
    CGRect keyFrame = [info.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];

    CGFloat tY = keyFrame.origin.y - self.view.frame.size.height - 64;

    self.view.transform = CGAffineTransformMakeTranslation(0, tY);
}