PinYin4Objc is a popular objective-c library supporting convertion between Chinese(both Simplified and Tranditional) characters and most popular Pinyin systems， it's performance is very efficient, data cached at first time, and use async method with block, this can avoid ui blocking, and runs smoothly. The output format of pinyin could be customized.(关键字：汉字转拼音，中文转拼音）