通过此链接，我找到了一种非常快捷，干净的方法。与Nirmit的答案相比，它缺少“加载指示器”，但是在代码行数方面胜出，并且不需要其他控件。我首先将该dispatch_cancelable_block.h文件添加到了我的项目（来自此repo），然后定义了以下类变量：__block dispatch_cancelable_block_t searchBlock;。

我的搜索代码现在看起来像这样：

- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText
{
    if (searchBlock != nil) {
        //We cancel the currently scheduled block
        cancel_block(searchBlock);
    }
    searchBlock = dispatch_after_delay(searchBlockDelay, ^{
        //We "enqueue" this block with a certain delay. It will be canceled if the user types faster than the delay, otherwise it will be executed after the specified delay
        [self loadPlacesAutocompleteForInput:searchText]; 
    });
}

笔记：

• 该loadPlacesAutocompleteForInput是金LPGoogleFunctions库
• searchBlockDelay在之外定义如下@implementation：

静态CGFloat searchBlockDelay = 0.2;