android:

管理类代码如下:

public class KapSearchRunnableHelper implements Runnable {
    private Runnable runnable = null;
    public KapSearchRunnableHelper(Runnable able){
        runnable = able;
    }
    private KapSearchRunnableHelper(){}//私有化
    Handler handler = new Handler();
    public void pushKeyWord(){
        handler.removeCallbacks(this);// 移除请求
        handler.postDelayed(this,500);// 添加请求
    }
    @Override
    public void run() {
        //此处发起Http请求
        runnable.run();
    }
}

使用如下:

final KapSearchRunnableHelper searchRunnableHelper = new KapSearchRunnableHelper(new Runnable() {
            @Override
            public void run() {
                postList(0);//网络请求
            }
        });
        editText.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
            }

            @Override
            public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
                //防止铺天盖地的请求 SearchRunnable管理
                searchRunnableHelper.pushKeyWord();
            }

            @Override
            public void afterTextChanged(Editable editable) {
            }
        });

参考：
Android支持单词提示搜索框的网络请求策略

iOS：

代码如下:

- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText {
    //实时搜索(连续输入的时候不请求)
    [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(postList:) object:searchBar];
    [self performSelector:@selector(postList:) withObject:searchBar afterDelay:0.1];
}

思路都是一样的～～～