正如代码中所示，这里对C++的IBinder和Parcel两个对象进行了封装，而Java的Service的底层实现也正是对这两个类进行封装的结果，具体的可以看
frameworks\base\core\jni\Android_util_Binder.cpp
的代码，
再来看下如何在Python中使用这些代码，这里用cython来封装这些C接口：
binder.pyx
cdef extern from "utils/Unicode.h":
ctypedef short char16_t
ctypedef unsigned int uint32_t
cdef extern from "Python.h":
ctypedef short Py_UNICODE
ctypedef size_t Py_ssize_t
object PyString_FromStringAndSize(const char *v, Py_ssize_t len)
int PyString_AsStringAndSize(object obj, char **buffer, Py_ssize_t *length)
object PyUnicode_FromUnicode(const Py_UNICODE *u, Py_ssize_t size)
Py_UNICODE* PyUnicode_AS_UNICODE(object)
Py_ssize_t PyUnicode_GetSize(object)
void Py_INCREF(object)
void Py_DECREF(object)
cdef extern from "binder_wrap.h":
ctypedef int (*vector_visitor)(const char16_t* str16,int length,void *data)
int binder_listServices(vector_visitor visitor,void *data)
ctypedef int (*fnOnTransact)(uint32_t code,const void *data,void *reply,uint32_t flags,void *userData)
int server_create(const char *name,const char *descriptor,fnOnTransact onTrans,void *data)
void* binder_getbinder(const char *name)
int binder_releasebinder(void* binder)
int binder_getInterfaceDescriptor(void *binder,char16_t *descriptor,int size)
int binder_transact(void* binder,int code,const void *data,void* reply,int flags)
void* parcel_new()
int parcel_destroy(void* parcel)
int parcel_writeInterfaceToken(void* parcel,const char *interface)
int parcel_writeInt32(void *parcel,int val)
int parcel_writeCString(void *parcel,const char* str)
int parcel_writeString16(void *parcel,const char16_t* str, size_t len)
int parcel_readInt32(void *parcel)
int parcel_readInt64(void *parcel)
int parcel_readString16(void *parcel,char16_t* str, size_t len)
int parcel_readExceptionCode(void *parcel)
int parcel_readInplace(void *parcel,void* data, int len)
int parcel_dataAvail(void *parcel)
cdef int visitor(const char16_t* str16,int length,void *data):
arr = <object>data
o = PyUnicode_FromUnicode(<Py_UNICODE*>str16,length)
arr.append(o)
def listServices():
arr = []
Py_INCREF(arr)
binder_listServices(visitor,<void *>arr)
Py_DECREF(arr)
return arr
cdef class Binder:
cdef void *ptr
def __cinit__(self,char *name): #, sp[IBinder] service):
self.ptr = binder_getbinder(name)
def __dealloc__(self):
binder_releasebinder(self.ptr)
def getInterfaceDescriptor(self):
cdef char16_t descriptor[256]
cdef int ret
ret = binder_getInterfaceDescriptor(self.ptr,descriptor,sizeof(descriptor))
if not ret:
return None
return PyUnicode_FromUnicode(<Py_UNICODE*>descriptor,ret)
def transact(self,int code,data,reply,int flags):
cdef int dataPtr = data.getNativePtr()
cdef int replyPtr = reply.getNativePtr()
binder_transact(self.ptr,code,<void *>dataPtr,<void*>replyPtr,flags)
return reply
cdef class Parcel:
cdef void *ptr
cdef int nativePtr
def __cinit__(self,unsigned int nativePtr=0): #, sp[IBinder] service):
self.nativePtr = nativePtr
if not nativePtr:
self.ptr = parcel_new()
else:
self.ptr = <void *>nativePtr
def __dealloc__(self):
if not self.nativePtr:
parcel_destroy(self.ptr)
def getNativePtr(self):
return <int>self.ptr
def writeInterfaceToken(self,const char *interface):
return parcel_writeInterfaceToken(<void *>self.ptr,interface)
def writeInt(self,int val):
self.writeInt32(val)
def writeInt32(self,int val):
return parcel_writeInt32(<void *>self.ptr,val)
def writeCString(self,const char* cstr):
return parcel_writeCString(<void *>self.ptr,cstr)
def writeString16(self,ustr):
cdef char16_t *un
cdef int size
if isinstance(ustr,unicode):
un = <char16_t*>PyUnicode_AS_UNICODE(ustr)
size = PyUnicode_GetSize(ustr)
return parcel_writeString16(<void *>self.ptr,un,size)
def readInt32(self):
return parcel_readInt32(self.ptr)
def readInt(self):
return self.readInt32()
def readInt64(self):
return parcel_readInt64(self.ptr)
def readExceptionCode(self):
return parcel_readExceptionCode(self.ptr)
def readString16(self):
cdef char16_t str16[256]
cdef int ret
ret = parcel_readString16(self.ptr,str16,sizeof(str16))
if not ret:
return None
return PyUnicode_FromUnicode(<Py_UNICODE*>str16,ret)
def readByteArray(self):
return self.createByteArray()
def createByteArray(self):
length = self.readInt()
print 'createByteArray:',length
return self.readInplace(length)
# int parcel_readInplace(void *parcel,void* data, size_t len)
def readInplace(self,length):
cdef char arr[512]
ret = parcel_readInplace(self.ptr,arr,length)
if ret == length:
return PyString_FromStringAndSize(arr,length)
else:
return None
# int parcel_dataAvail(void *parcel)
def dataAvail(self):
return parcel_dataAvail(self.ptr)
def createTypedArrayList(self,creator):
N = self.readInt()
if N <= 0:
return None
arr = []
for i in range(N):
if self.readInt() == 0:
continue
else:
result = creator.createFromParcel(self)
arr.append(result)
return arr
@classmethod
def obtain(cls):
return Parcel()
@classmethod
def recycle(cls):
pass
好，再来看看如何来实现访问WifiService的功能：
WifiService.py
from binder import Binder,Parcel
WIFI_SERVICE = "wifi";
DESCRIPTOR = "android.net.wifi.IWifiManager";
FIRST_CALL_TRANSACTION = 1
TRANSACTION_getConfiguredNetworks = (FIRST_CALL_TRANSACTION + 0);
TRANSACTION_addOrUpdateNetwork = (FIRST_CALL_TRANSACTION + 1);
TRANSACTION_removeNetwork = (FIRST_CALL_TRANSACTION + 2);
TRANSACTION_enableNetwork = (FIRST_CALL_TRANSACTION + 3);
TRANSACTION_disableNetwork = (FIRST_CALL_TRANSACTION + 4);
TRANSACTION_pingSupplicant = (FIRST_CALL_TRANSACTION + 5);
TRANSACTION_startScan = (FIRST_CALL_TRANSACTION + 6);
TRANSACTION_getScanResults = (FIRST_CALL_TRANSACTION + 7);
TRANSACTION_disconnect = (FIRST_CALL_TRANSACTION + 8);
TRANSACTION_reconnect = (FIRST_CALL_TRANSACTION + 9);
TRANSACTION_reassociate = (FIRST_CALL_TRANSACTION + 10);
TRANSACTION_getConnectionInfo = (FIRST_CALL_TRANSACTION + 11);
TRANSACTION_setWifiEnabled = (FIRST_CALL_TRANSACTION + 12);
TRANSACTION_getWifiEnabledState = (FIRST_CALL_TRANSACTION + 13);
TRANSACTION_setCountryCode = (FIRST_CALL_TRANSACTION + 14);
TRANSACTION_setFrequencyBand = (FIRST_CALL_TRANSACTION + 15);
TRANSACTION_getFrequencyBand = (FIRST_CALL_TRANSACTION + 16);
TRANSACTION_isDualBandSupported = (FIRST_CALL_TRANSACTION + 17);
TRANSACTION_saveConfiguration = (FIRST_CALL_TRANSACTION + 18);
TRANSACTION_getDhcpInfo = (FIRST_CALL_TRANSACTION + 19);
TRANSACTION_acquireWifiLock = (FIRST_CALL_TRANSACTION + 20);
TRANSACTION_updateWifiLockWorkSource = (FIRST_CALL_TRANSACTION + 21);
TRANSACTION_releaseWifiLock = (FIRST_CALL_TRANSACTION + 22);
TRANSACTION_initializeMulticastFiltering = (FIRST_CALL_TRANSACTION + 23);
TRANSACTION_isMulticastEnabled = (FIRST_CALL_TRANSACTION + 24);
TRANSACTION_acquireMulticastLock = (FIRST_CALL_TRANSACTION + 25);
TRANSACTION_releaseMulticastLock = (FIRST_CALL_TRANSACTION + 26);
TRANSACTION_setWifiApEnabled = (FIRST_CALL_TRANSACTION + 27);
TRANSACTION_getWifiApEnabledState = (FIRST_CALL_TRANSACTION + 28);
TRANSACTION_getWifiApConfiguration = (FIRST_CALL_TRANSACTION + 29);
TRANSACTION_setWifiApConfiguration = (FIRST_CALL_TRANSACTION + 30);
TRANSACTION_startWifi = (FIRST_CALL_TRANSACTION + 31);
TRANSACTION_stopWifi = (FIRST_CALL_TRANSACTION + 32);
TRANSACTION_addToBlacklist = (FIRST_CALL_TRANSACTION + 33);
TRANSACTION_clearBlacklist = (FIRST_CALL_TRANSACTION + 34);
TRANSACTION_getWifiServiceMessenger = (FIRST_CALL_TRANSACTION + 35);
TRANSACTION_getWifiStateMachineMessenger = (FIRST_CALL_TRANSACTION + 36);
TRANSACTION_getConfigFile = (FIRST_CALL_TRANSACTION + 37);
TRANSACTION_captivePortalCheckComplete = (FIRST_CALL_TRANSACTION + 38);
mRemote = Binder(WIFI_SERVICE)
def transact(TRANSACTION):
_data = Parcel()
_reply = Parcel()
_data.writeInterfaceToken(DESCRIPTOR)
mRemote.transact(TRANSACTION, _data, _reply, 0)
_reply.readExceptionCode()
return _reply.readInt32()
def getConfiguredNetworks():
pass
def addOrUpdateNetwork():
pass
def removeNetwork():
pass
def enableNetwork(netId,disableOthers):
_data = Parcel()
_reply = Parcel()
_data.writeInterfaceToken(DESCRIPTOR)
_data.writeInt32(netId)
if disableOthers:
_data.writeInt32(1)
else:
_data.writeInt32(0)
mRemote.transact(TRANSACTION_enableNetwork, _data, _reply, 0)
_reply.readExceptionCode()
return _reply.readInt32() != 0
def disableNetwork(netId):
_data = Parcel()
_reply = Parcel()
_data.writeInterfaceToken(DESCRIPTOR)
_data.writeInt32(netId)
mRemote.transact(TRANSACTION_disableNetwork, _data, _reply, 0)
_reply.readExceptionCode()
return _reply.readInt32() != 0
def pingSupplicant():
_data = Parcel()
_reply = Parcel()
_data.writeInterfaceToken(DESCRIPTOR)
mRemote.transact(TRANSACTION_pingSupplicant, _data, _reply, 0)
_reply.readExceptionCode()
return _reply.readInt32() != 0
def startScan(forceActive):
_data = Parcel()
_reply = Parcel()
ret = 0
try:
_data.writeInterfaceToken(DESCRIPTOR)
if forceActive:
_data.writeInt(1)
else:
_data.writeInt(0)
mRemote.transact(TRANSACTION_startScan, _data, _reply, 0)
ret = _reply.readExceptionCode()
finally:
_reply.recycle()
_data.recycle()
return ret == 0
class ScanResult:
def __init__(self,ssid,bssid,caps,level,frequency,timestamp):
self.ssid = ssid
self.bssid = bssid
self.caps = caps
self.level = level
self.frequency = frequency
self.timestamp = timestamp
@classmethod
def createFromParcel(cls,reply):
has_ssid = reply.readInt32()
ssid = None
if has_ssid:
ssid_lengt = reply.readInt()
ssid = reply.readByteArray()
BSSID = reply.readString16()
caps = reply.readString16()
level = reply.readInt()
frequency = reply.readInt()
timestamp = reply.readInt64()
print 'BSSID:',BSSID
print 'caps:',caps
print 'level:',level
print 'frequency:',frequency
print 'timestamp:',timestamp
return ScanResult(ssid,BSSID,caps,level,frequency,timestamp)
def getScanResults():
_data = Parcel.obtain()
_reply = Parcel.obtain()
_result = None
try:
_data.writeInterfaceToken(DESCRIPTOR)
mRemote.transact(TRANSACTION_getScanResults, _data, _reply, 0)
if 0 != _reply.readExceptionCode():
return None
_result = _reply.createTypedArrayList(ScanResult)
finally:
_reply.recycle()
_data.recycle()
return _result
def disconnect():
return transact(TRANSACTION_disconnect) != 0
def reconnect():
return transact(TRANSACTION_reconnect) != 0
def reassociate():
return transact(TRANSACTION_reassociate) != 0
"""
class WifiInfo:
def __init__():
pass
@classmethod
def createFromParcel(cls,r):
info = WifiInfo();
info.networkId = r.readInt32()
info.rssi = r.readInt32()
info.linkSpeed = r.readInt32()
if r.readByte() == 1:
info.setInetAddress(InetAddress.getByAddress(in.createByteArray()))
if r.readInt() == 1:
info.mWifiSsid = WifiSsid.CREATOR.createFromParcel(r)
info.mBSSID = r.readString16()
info.mMacAddress = r.readString16()
info.mMeteredHint = r.readInt32() != 0
"""
def getConnectionInfo():
pass
def setWifiEnabled(enable):
_data = Parcel()
_reply = Parcel()
_data.writeInterfaceToken(DESCRIPTOR)
if enable:
_data.writeInt32(1)
else:
_data.writeInt32(0)
mRemote.transact(TRANSACTION_setWifiEnabled, _data,_reply,0)
_reply.readExceptionCode()
_result = (0!=_reply.readInt32())
return _result;
def getWifiEnabledState():
return transact(TRANSACTION_getWifiEnabledState)
def setCountryCode(country,persist):
_data = Parcel()
_reply = Parcel()
_data.writeInterfaceToken(DESCRIPTOR)
if isinstance(country,str):
country = unicode(contry)
_data.writeString16(country)
if persist:
_data.writeInt32(1)
else:
_data.writeInt32(0)
mRemote.transact(TRANSACTION_setCountryCode, _data,_reply,0)
_reply.readExceptionCode()
_result = (0!=_reply.readInt32())
return _result;
def setFrequencyBand(band, persist):
_data = Parcel()
_reply = Parcel()
_data.writeInterfaceToken(DESCRIPTOR)
if isinstance(country,str):
country = unicode(contry)
_data.writeInt32(band)
if persist:
_data.writeInt32(1)
else:
_data.writeInt32(0)
mRemote.transact(TRANSACTION_setFrequencyBand, _data,_reply,0)
_reply.readExceptionCode()
_result = (0!=_reply.readInt32())
return _result;
def getFrequencyBand():
return transact(TRANSACTION_getFrequencyBand)
def isDualBandSupported():
return transact(TRANSACTION_isDualBandSupported) != 0
def saveConfiguration():
pass
def get_readable_address(addr):
return "%d:%d:%d:%d"%(addr&0xff,(addr>>8)&0xff,(addr>>16)&0xff,(addr>>24)&0xff)
def getDhcpInfo():
_data = Parcel()
_reply = Parcel()
_data.writeInterfaceToken(DESCRIPTOR)
mRemote.transact(TRANSACTION_getDhcpInfo, _data,_reply,0)
_reply.readExceptionCode()
if 0 == _reply.readInt32():
return None
ipAddress = get_readable_address(reply.readInt32());
gateway = get_readable_address(reply.readInt32());
netmask = get_readable_address(reply.readInt32());
dns1 = get_readable_address(reply.readInt32());
dns2 = get_readable_address(reply.readInt32());
serverAddress = get_readable_address(reply.readInt32());
leaseDuration = get_readable_address(reply.readInt32());
info = (ipAddress,gateway,netmask,dns1,dns2,serverAddress,leaseDuration)
print "ipAddress %s,\ngateway %s,\nnetmask %s,\ndns1 %s,\ndns2 %s,\nserverAddress %s,\nleaseDuration %s"%info
return info
def acquireWifiLock():
pass
def updateWifiLockWorkSource():
pass
def releaseWifiLock():
pass
def initializeMulticastFiltering():
pass
def isMulticastEnabled():
pass
def acquireMulticastLock():
pass
def releaseMulticastLock():
pass
def setWifiApEnabled(wifiConfig,enable):
_data = Parcel()
_reply = Parcel()
_data.writeInterfaceToken(DESCRIPTOR)
if wifiConfig:
_data.writeInt32(1)
wifiConfig.writeToParcel(_data)
else:
_data.writeInt32(0)
if enable:
_data.writeInt32(1)
else:
_data.writeInt32(0)
mRemote.transact(TRANSACTION_setWifiApEnabled, _data,_reply,0)
_reply.readExceptionCode()
def getWifiApEnabledState():
return transact(TRANSACTION_getWifiApEnabledState)
def getWifiApConfiguration():
pass
def setWifiApConfiguration():
pass
def startWifi():
return transact(TRANSACTION_startWifi)
def stopWifi():
return transact(TRANSACTION_stopWifi)
def addToBlacklist(bssid):
_data = Parcel()
_reply = Parcel()
_data.writeInterfaceToken(DESCRIPTOR)
if isinstance(bssid,str):
bssid = unicode(bssid)
_data.writeString16(bssid)
mRemote.transact(TRANSACTION_addToBlacklist, _data,_reply,0)
_reply.readExceptionCode()
def clearBlacklist():
return transact(TRANSACTION_clearBlacklist)
def getWifiServiceMessenger():
pass
def getWifiStateMachineMessenger():
pass
def getConfigFile():
_data = Parcel()
_reply = Parcel()
_data.writeInterfaceToken(DESCRIPTOR)
mRemote.transact(TRANSACTION_getConfigFile, _data,_reply,0)
_reply.readExceptionCode()
return _reply.readString16()
def captivePortalCheckComplete():
return transact(TRANSACTION_captivePortalCheckComplete) != 0