Android官方API文档完整版,内容参考:onBindpublicfinalIBinderonBind(Intentintent)从类Service复制的描述Returnthecommunicationchanneltotheservice.Mayreturnnullifclientscannotbindtotheservice.ThereturnedIBinderisusuallyforacomplexinterfacethathasbeendescribedusingaidl.Notethatunlikeotherapplicationcomponent