一个UISrcollView中多个UITextField的滚动处理

摘译自: http://stackoverflow.com/questions/484855/how-programatically-move-a-uiscrollview-to-focus-in-a-control-above-keyboard

使用一个实例变量记录视图在为键盘调整之前的位置，以用于当UITextField返回时恢复到之前的状态。

//header
@interface TheViewController : UIViewController <UITextFieldDelegate> {
    CGPoint svos;
}
//implementation
- (void)textFieldDidBeginEditing:(UITextField *)textField {
    svos = scrollView.contentOffset;
    CGPoint pt;
    CGRect rc = [textField bounds];
    rc = [textField convertRect:rc toView:scrollView];
    pt = rc.origin;
    pt.x = 0;
    pt.y -= 60;
    [scrollView setContentOffset:pt animated:YES];           
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField {
    [scrollView setContentOffset:svos animated:YES]; 
    [textField resignFirstResponder];
    return YES;
}