Kivy A to Z — 怎样从python代码中直接訪问Android的Service「建议收藏」

大家好，又见面了，我是全栈君。

在Kivy中，通过pyjnius扩展能够间接调用Java代码，而pyjnius利用的是Java的反射机制。可是在Python对象和Java对象中转来转去总让人感觉到十分别扭。好在android提供了binder这个进程间通信的功能，Java中的Service也是基于Binder的C++代码封装来实现进程间通信的，这也为从Python代码中绕开pyjnius直接訪问Java代码提供了可能，既然Java的Service是基于C++的封装来实现的，也相同能够在Python中封装相同的C++代码，这篇文章解说了怎样通过binder在Python代码中直接訪问Java的Service。如WifiService。

binder_wrap.h

#ifndef BINDER_WRAP_H
#define BINDER_WRAP_H


#ifdef __cplusplus
extern "C" {
#endif

typedef int (*vector_visitor)(const char16_t* str16,int length,void *data);
typedef 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_listServices(vector_visitor visitor,void *data);
int binder_getInterfaceDescriptor(void *binder,char16_t *descriptor,size_t 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);
long parcel_readInt64(void *parcel);
int parcel_readString16(void *parcel,char16_t* str, size_t len);
int parcel_readInplace(void *parcel,void* data, int len);
int parcel_readExceptionCode(void *parcel);
int parcel_dataAvail(void *parcel);

#ifdef __cplusplus
}
#endif

#endif

binder_wrap.cpp

#include <sys/types.h>
#include <unistd.h>
#include <grp.h>

#include <binder/IPCThreadState.h>
#include <binder/ProcessState.h>
#include <binder/IServiceManager.h>
#include <utils/Log.h>

#include <binder/Parcel.h>

#include "binder_wrap.h"

using namespace android;

void* binder_getbinder(const char *name)
{
    android::sp<android::IServiceManager> sm = android::defaultServiceManager();
    sp<IBinder> *binder = new sp<IBinder>();
    do {
        *binder = sm->getService(android::String16(name));
        if (binder != 0)
        {
            break;
        }
        usleep(500000); // 0.5 s
    } while(true);
    return reinterpret_cast<void *>(binder);
}

int binder_releasebinder(void* binder)
{
    sp<IBinder> *bp = reinterpret_cast<sp<IBinder> *>(binder);

    if(bp == 0)
    {
        return 0;
    }

    delete bp;
    
    return 1;
}

//Vector<String16>    listServices() = 0;
int binder_listServices(vector_visitor visitor,void *data)
{
    android::sp<android::IServiceManager> sm = android::defaultServiceManager();

    Vector<String16> list = sm->listServices();

    for (int i=0;i<list.size();i++)
    {
        visitor(list[i].string(),list[i].size(),data);
    }
    
    return list.size();
}

int binder_getInterfaceDescriptor(void *binder,char16_t *descriptor,size_t size)
{
    sp<IBinder> *bp = reinterpret_cast<sp<IBinder> *>(binder);

    if(bp == 0)
    {
        return 0;
    }
    
    if (descriptor == NULL || size <= 0)
    {
        return 0;
    }
    
    String16 des = (*bp)->getInterfaceDescriptor();

    if (size > des.size())
    {
        size = des.size();
    }

    memcpy(descriptor,des.string(),size*2);

    return size;
}

//int binder_transact(void* binder,int code,const Parcel& data,Parcel* reply,int flags = 0)
int binder_transact(void* binder,int code,const void *data,void* reply,int flags)
{
    sp<IBinder> *bp = reinterpret_cast<sp<IBinder> *>(binder);
 
    if(bp == 0 || data == 0 || reply == 0)
    {
        return 0;
    }
    return (*bp)->transact(code,*(Parcel*)data,(Parcel*)reply,flags);
}

void* parcel_new()
{
    return (void*)new Parcel();
}

int parcel_destroy(void* parcel)
{
    if(parcel == 0)
    {
        return 0;
    }
    delete (Parcel*)parcel;
    return 1;
}

int parcel_writeInterfaceToken(void* parcel,const char *interface)
{
    Parcel *p = reinterpret_cast<Parcel *>(parcel);
    
    if(p == 0)
    {
        return 0;
    }
    return p->writeInterfaceToken(String16(interface));
}

int parcel_writeInt32(void *parcel,int val)
{
    Parcel *p = reinterpret_cast<Parcel *>(parcel);
    
    if(p == 0)
    {
        return 0;
    }

    return p->writeInt32(val);
}

int parcel_writeCString(void *parcel,const char* str)
{
    Parcel *p = reinterpret_cast<Parcel *>(parcel);

    if(p == 0)
    {
        return 0;
    }
    return p->writeCString(str);
}

int parcel_writeString16(void *parcel,const char16_t* str, size_t len)
{
    Parcel *p = reinterpret_cast<Parcel *>(parcel);
    
    if(p == 0)
    {
        return 0;
    }
    
    if (str == 0 || len <= 0)
    {
        return 0;
    }
    
    return p->writeString16(str,len);
}


int parcel_readInt32(void *parcel)
{
    Parcel *p = reinterpret_cast<Parcel *>(parcel);
    
    if(p == 0)
    {
        return 0;
    }
    return p->readInt32();
}

long parcel_readInt64(void *parcel)
{
    Parcel *p = reinterpret_cast<Parcel *>(parcel);

    if(p == 0)
    {
        return 0;
    }
    return p->readInt64();
}

int parcel_readString16(void *parcel,char16_t* str, size_t len)
{
    Parcel *p = reinterpret_cast<Parcel *>(parcel);

    if(p == 0)
    {
        return 0;
    }

    if (str == NULL || len <= 0)
    {
        return 0;
    }
    
    String16 str16 = p->readString16();
    
    if (len > str16.size())
    {
        len = str16.size();
    }
    
    memcpy(str,str16.string(),len*2);

    return len;
}

int parcel_readExceptionCode(void *parcel)
{
    Parcel *p = reinterpret_cast<Parcel *>(parcel);

    if(p == 0)
    {
        return 0;
    }
    return p->readExceptionCode();
}


int parcel_readInplace(void *parcel,void* data, int len)
{
    Parcel *p = reinterpret_cast<Parcel *>(parcel);

    if(p == 0)
    {
        return 0;
    }

    if (len >= 0 && len <= (int32_t)p->dataAvail())
    {
        const void *d = p->readInplace(len);
        memcpy(data,d,len);
        return len;
    }
    return 0;
}

int parcel_dataAvail(void *parcel)
{
    Parcel *p = reinterpret_cast<Parcel *>(parcel);

    if(p == 0)
    {
        return 0;
    }

    return p->dataAvail();
    
}

正如代码中所看到的，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，详细的能够看

frameworks\base\core\jni\android_util_Binder.cpp

的代码。

再来看下怎样在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，再来看看怎样来实现訪问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

眼下并没有实现全部的WifiService的功能，可是像startScan。getScanResults,setWifiEnabled,getWifiEnabledState,getDhcpInfo,setWifiApEnabled这些基本的接口已经实现了，其他接口没有实现并不是是由于不能实现，而是比較繁琐，临时未实现而己，后面会不断的完好。

再来看下測试代码：

test.py

import WifiService WifiService.setWifiEnabled(True) WifiService.startScan(True) print WifiService.pingSupplicant() print WifiService.getConfigFile() for i in range(10): time.sleep(1.0) result = WifiService.getScanResults() if result: print result break

运行后将会打印出搜索到的Wifi信息。

另外就是代码的编译问题了。

代码必须在android的源码下进行编译。我试过在ndk上进行编译，经过一番努力，通过链接事先编译好的C++ binder库。也成功编译通过，可是程序不能正常执行。这应该是预先编译出来的库和ndk的库存在兼容性问题造成的。也许通过在ndk上编译binder库能够避免这个问题。可是眼下还没有作过尝试。可是编译出来的代码应该能够执行在各个不同的版本号，我在4.0和4.2版本号的设备上作了简单的測试，事实证明在4.2上编译的代码能够在4.0上执行，可是考虑到android的诸多版本号，各个版本号多多少少有些兼容性问题，更具体的还必须比較各个版本号的binder代码。并通过測试才干得到结果。

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