修改getLeafItems在没有data参数时报错的bug

没传参数，就返回全部叶子节点
修复把字符串当做了数组处理的bug

修复把字符串当做了数组处理的bug
修复searchBox为null时依然解绑事件的bug

修复searchBox为null时依然解绑事件的bug
Revert "修复searchBox为null时依然解绑事件的bug"

This reverts commit db41d7aef85670f046e472025fda5c0c8615af6e.
Revert "Revert "修复searchBox为null时依然解绑事件的bug""

This reverts commit 4600dd696003703b048e9f22dac7c3f77b079f13.