iOS解决键盘遮挡输入框的问题

-(void)textFieldDidBeginEditing:(UITextField *)textField{
  CGRect frame = textField.frame;
  int offset = frame.origin.y + 100 - (UISCREEN_HEIGHT - 480.0);//键盘高度
  NSTimeInterval animationDuration = 0.30f;
  [UIView beginAnimations:@"ResizeForKeyboard" context:nil];
  [UIView setAnimationDuration:animationDuration];
  
  //将视图的Y坐标向上移动offset个单位，以使下面腾出地方用于软键盘的显示
  if(offset > 0)
    self.view.frame = CGRectMake(0.0f, -offset, UISCREEN_WIDTH, UISCREEN_HEIGHT);
  [UIView commitAnimations];
}

-(BOOL)textFieldShouldReturn:(UITextField *)textField {//按“完成”隐藏键盘
  [textField resignFirstResponder];//隐藏输入键盘
  return YES;
}

//输入框编辑完成以后，将视图恢复到原始状态
-(void)textFieldDidEndEditing:(UITextField *)textField{
  self.view.frame = CGRectMake(0, 0, UISCREEN_WIDTH, UISCREEN_HEIGHT);
}