Ios UITextField-未设置新帧（在动画中）

我想，搜索字段变形为

targetFrame

#1这不是结果：

- (BOOL)searchBarShouldBeginEditing:(UISearchBar *)bar
{
    UITextField *searchField = [bar valueForKey:@"_searchField"];
    CGRect targetFrame =  CGRectMake(-50, 0, 200, 30);
    searchField.frame = targetFrame; //not result

    return YES;
}

- (BOOL)searchBarShouldBeginEditing:(UISearchBar *)bar
{
    UITextField *searchField = [bar valueForKey:@"_searchField"];
    searchField.frame = CGRectMake (10, 0, 200, 50); //must differ from CGRectZero

    [UIView animateWithDuration: 3.0
                     animations: ^{

                     CGRect targetFrame =  CGRectMake(-50, 0, 200, 30);
                     searchField.frame = targetFrame; 

    }];

    return YES;
}

#2不正确，但转换：

- (BOOL)searchBarShouldBeginEditing:(UISearchBar *)bar
{
    UITextField *searchField = [bar valueForKey:@"_searchField"];
    CGRect targetFrame =  CGRectMake(-50, 0, 200, 30);
    searchField.frame = targetFrame; //not result

    return YES;
}

- (BOOL)searchBarShouldBeginEditing:(UISearchBar *)bar
{
    UITextField *searchField = [bar valueForKey:@"_searchField"];
    searchField.frame = CGRectMake (10, 0, 200, 50); //must differ from CGRectZero

    [UIView animateWithDuration: 3.0
                     animations: ^{

                     CGRect targetFrame =  CGRectMake(-50, 0, 200, 30);
                     searchField.frame = targetFrame; 

    }];

    return YES;
}

然后使用#2，searchField启动动画，但设置为默认大小（而不是

targetFrame

）

我想把搜索字段转换成

targetFrame

PS

searchField.autoresizingMask=UIViewAutoResizingOne非结果
尝试以下程序块：

   [UIView animateWithDuration:3.0
                          delay:0
                        options:UIViewAnimationOptionLayoutSubviews
                     animations:^{
                         CGRect targetFrame =  CGRectMake(-50, 0, 200, 30);
                         searchField.frame = targetFrame; 
                     }
                     completion:^(BOOL finished) {

   }];