iOS 键盘弹出遮挡输入框

 #pragma mark 键盘弹出遮挡输入框

 //开始编辑输入框的时候，软键盘出现，执行此事件
 -(void)textFieldDidBeginEditing:(UITextField *)textField
 {
     CGRect frame = textField.frame;
     int offset = frame.origin.y +  - (self.view.frame.size.height - 216.0);//键盘高度216

     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 > )
         self.view.frame = CGRectMake(0.0f, -offset, self.view.frame.size.width, self.view.frame.size.height);

     [UIView commitAnimations];
 }

 //当用户按下return键或者按回车键，keyboard消失
 -(BOOL)textFieldShouldReturn:(UITextField *)textField
 {
     [textField resignFirstResponder];
     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(, , self.view.frame.size.width, self.view.frame.size.height);
 }