前面文章讲解了Android的蓝牙基本用法，本文讲得深入些，探讨下蓝牙方面的隐藏API。用过Android系统设置(Setting)的人都知道蓝牙搜索之后可以建立配对和解除配对，但是这两项功能的函数没有在SDK中给出，那么如何去使用这两项功能呢？本文利用JAVA的反射机制去调用这两项功能对应的函数：createBond和removeBond，具体的发掘和实现步骤如下：

1.使用Git工具下载platform/packages/apps/Settings.git，在Setting源码中查找关于建立配对和解除配对的API，知道这两个API的宿主(BluetoothDevice)；

2.使用反射机制对BluetoothDevice枚举其所有方法和常量，看看是否存在:

static public void printAllInform(Class clsShow) {

try {

// 取得所有方法

Method[] hideMethod = clsShow.getMethods();

int i = 0;

for (; i < hideMethod.length; i++) {

Log.e("method name", hideMethod[i].getName());

}

// 取得所有常量

Field[] allFields = clsShow.getFields();

for (i = 0; i < allFields.length; i++) {

Log.e("Field name", allFields[i].getName());

}

} catch (SecurityException e) {

// throw new RuntimeException(e.getMessage());

e.printStackTrace();

} catch (IllegalArgumentException e) {

// throw new RuntimeException(e.getMessage());

e.printStackTrace();

} catch (Exception e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

结果如下：

11-29 09:19:12.012: method name(452): cancelBondProcess

11-29 09:19:12.020: method name(452): cancelPairingUserInput

11-29 09:19:12.020: method name(452): createBond11-29 09:19:12.020: method name(452): createInsecureRfcommSocket

11-29 09:19:12.027: method name(452): createRfcommSocket

11-29 09:19:12.027: method name(452): createRfcommSocketToServiceRecord

11-29 09:19:12.027: method name(452): createScoSocket

11-29 09:19:12.027: method name(452): describeContents

11-29 09:19:12.035: method name(452): equals

11-29 09:19:12.035: method name(452): fetchUuidsWithSdp

11-29 09:19:12.035: method name(452): getAddress

11-29 09:19:12.035: method name(452): getBluetoothClass

11-29 09:19:12.043: method name(452): getBondState

11-29 09:19:12.043: method name(452): getName

11-29 09:19:12.043: method name(452): getServiceChannel

11-29 09:19:12.043: method name(452): getTrustState

11-29 09:19:12.043: method name(452): getUuids

11-29 09:19:12.043: method name(452): hashCode

11-29 09:19:12.043: method name(452): isBluetoothDock

11-29 09:19:12.043: method name(452): removeBond11-29 09:19:12.043: method name(452): setPairingConfirmation

11-29 09:19:12.043: method name(452): setPasskey

11-29 09:19:12.043: method name(452): setPin

11-29 09:19:12.043: method name(452): setTrust

11-29 09:19:12.043: method name(452): toString

11-29 09:19:12.043: method name(452): writeToParcel

11-29 09:19:12.043: method name(452): convertPinToBytes

11-29 09:19:12.043: method name(452): getClass

11-29 09:19:12.043: method name(452): notify

11-29 09:19:12.043: method name(452): notifyAll

11-29 09:19:12.043: method name(452): wait

11-29 09:19:12.051: method name(452): wait

11-29 09:19:12.051: method name(452): wait

3.如果枚举发现API存在(SDK却隐藏)，则自己实现调用方法：

/**

* 与设备配对 参考源码：platform/packages/apps/Settings.git

* /Settings/src/com/android/settings/bluetooth/CachedBluetoothDevice.java

*/

static public boolean createBond(Class btClass,BluetoothDevice btDevice) throws Exception {

Method createBondMethod = btClass.getMethod("createBond");

Boolean returnValue = (Boolean) createBondMethod.invoke(btDevice);

return returnValue.booleanValue();

}

/**

* 与设备解除配对 参考源码：platform/packages/apps/Settings.git

* /Settings/src/com/android/settings/bluetooth/CachedBluetoothDevice.java

*/

static public boolean removeBond(Class btClass,BluetoothDevice btDevice) throws Exception {

Method removeBondMethod = btClass.getMethod("removeBond");

Boolean returnValue = (Boolean) removeBondMethod.invoke(btDevice);

return returnValue.booleanValue();

}

此处注意:SDK之所以不给出隐藏的API肯定有其原因，也许是出于安全性或者是后续版本兼容性的考虑，因此不能保证隐藏API能在所有Android平台上很好地运行。

本文程序运行效果如下图所示：

main.xml源码如下：

android:orientation="vertical" android:layout_width="fill_parent"

android:layout_height="fill_parent">

android:layout_height="wrap_content" android:layout_width="fill_parent">

android:text="Search" android:layout_width="160dip">

android:layout_width="160dip" android:text="Show" android:id="@+id/btnShow">

android:layout_width="wrap_content" android:layout_height="wrap_content">

android:layout_height="fill_parent">

工具类ClsUtils.java源码如下：

package com.testReflect;

import java.lang.reflect.Field;

import java.lang.reflect.Method;

import android.bluetooth.BluetoothDevice;

import android.util.Log;

public class ClsUtils {

/**

* 与设备配对 参考源码：platform/packages/apps/Settings.git

* /Settings/src/com/android/settings/bluetooth/CachedBluetoothDevice.java

*/

static public boolean createBond(Class btClass,BluetoothDevice btDevice) throws Exception {

Method createBondMethod = btClass.getMethod("createBond");

Boolean returnValue = (Boolean) createBondMethod.invoke(btDevice);

return returnValue.booleanValue();

}

/**

* 与设备解除配对 参考源码：platform/packages/apps/Settings.git

* /Settings/src/com/android/settings/bluetooth/CachedBluetoothDevice.java

*/

static public boolean removeBond(Class btClass,BluetoothDevice btDevice) throws Exception {

Method removeBondMethod = btClass.getMethod("removeBond");

Boolean returnValue = (Boolean) removeBondMethod.invoke(btDevice);

return returnValue.booleanValue();

}

/**

*

* @param clsShow

*/

static public void printAllInform(Class clsShow) {

try {

// 取得所有方法

Method[] hideMethod = clsShow.getMethods();

int i = 0;

for (; i < hideMethod.length; i++) {

Log.e("method name", hideMethod[i].getName());

}

// 取得所有常量

Field[] allFields = clsShow.getFields();

for (i = 0; i < allFields.length; i++) {

Log.e("Field name", allFields[i].getName());

}

} catch (SecurityException e) {

// throw new RuntimeException(e.getMessage());

e.printStackTrace();

} catch (IllegalArgumentException e) {

// throw new RuntimeException(e.getMessage());

e.printStackTrace();

} catch (Exception e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

主程序testReflect.java的源码如下：

package com.testReflect;

import java.util.ArrayList;

import java.util.List;

import android.app.Activity;

import android.bluetooth.BluetoothAdapter;

import android.bluetooth.BluetoothDevice;

import android.content.BroadcastReceiver;

import android.content.Context;

import android.content.Intent;

import android.content.IntentFilter;

import android.os.Bundle;

import android.util.Log;

import android.view.View;

import android.widget.AdapterView;

import android.widget.ArrayAdapter;

import android.widget.Button;

import android.widget.ListView;

import android.widget.Toast;

public class testReflect extends Activity {

Button btnSearch, btnShow;

ListView lvBTDevices;

ArrayAdapter adtDevices;

List lstDevices = new ArrayList();

BluetoothDevice btDevice;

BluetoothAdapter btAdapt;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

btnSearch = (Button) this.findViewById(R.id.btnSearch);

btnSearch.setOnClickListener(new ClickEvent());

btnShow = (Button) this.findViewById(R.id.btnShow);

btnShow.setOnClickListener(new ClickEvent());

lvBTDevices = (ListView) this.findViewById(R.id.ListView01);

adtDevices = new ArrayAdapter(testReflect.this,

android.R.layout.simple_list_item_1, lstDevices);

lvBTDevices.setAdapter(adtDevices);

lvBTDevices.setOnItemClickListener(new ItemClickEvent());

btAdapt = BluetoothAdapter.getDefaultAdapter();// 初始化本机蓝牙功能

if (btAdapt.getState() == BluetoothAdapter.STATE_OFF)// 开蓝牙

btAdapt.enable();

// 注册Receiver来获取蓝牙设备相关的结果

IntentFilter intent = new IntentFilter();

intent.addAction(BluetoothDevice.ACTION_FOUND);

intent.addAction(BluetoothDevice.ACTION_BOND_STATE_CHANGED);

registerReceiver(searchDevices, intent);

}

private BroadcastReceiver searchDevices = new BroadcastReceiver() {

public void onReceive(Context context, Intent intent) {

String action = intent.getAction();

Bundle b = intent.getExtras();

Object[] lstName = b.keySet().toArray();

// 显示所有收到的消息及其细节

for (int i = 0; i < lstName.length; i++) {

String keyName = lstName[i].toString();

Log.e(keyName, String.valueOf(b.get(keyName)));

}

// 搜索设备时，取得设备的MAC地址

if (BluetoothDevice.ACTION_FOUND.equals(action)) {

BluetoothDevice device = intent

.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);

if (device.getBondState() == BluetoothDevice.BOND_NONE) {

String str = "未配对|" + device.getName() + "|" + device.getAddress();

lstDevices.add(str); // 获取设备名称和mac地址

adtDevices.notifyDataSetChanged();

}

}

}

};

class ItemClickEvent implements AdapterView.OnItemClickListener {

@Override

public void onItemClick(AdapterView> arg0, View arg1, int arg2,

long arg3) {

btAdapt.cancelDiscovery();

String str = lstDevices.get(arg2);

String[] values = str.split("//|");

String address=values[2];

btDevice = btAdapt.getRemoteDevice(address);

try {

if(values[0].equals("未配对"))

{

Toast.makeText(testReflect.this, "由未配对转为已配对", 500).show();

ClsUtils.createBond(btDevice.getClass(), btDevice);

}

else if(values[0].equals("已配对"))

{

Toast.makeText(testReflect.this, "由已配对转为未配对", 500).show();

ClsUtils.removeBond(btDevice.getClass(), btDevice);

}

} catch (Exception e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

/**

* 按键处理

* @author GV

*

*/

class ClickEvent implements View.OnClickListener {

@Override

public void onClick(View v) {

if (v == btnSearch) {//搜索附近的蓝牙设备

lstDevices.clear();

Object[] lstDevice = btAdapt.getBondedDevices().toArray();

for (int i = 0; i < lstDevice.length; i++) {

BluetoothDevice device=(BluetoothDevice)lstDevice[i];

String str = "已配对|" + device.getName() + "|" + device.getAddress();

lstDevices.add(str); // 获取设备名称和mac地址

adtDevices.notifyDataSetChanged();

}

// 开始搜索

setTitle("本机蓝牙地址：" + btAdapt.getAddress());

btAdapt.startDiscovery();

}

else if(v==btnShow){//显示BluetoothDevice的所有方法和常量，包括隐藏API

ClsUtils.printAllInform(btDevice.getClass());

}

}

}

}

希望本文实例能够对大家进行Android程序开发有一定的借鉴帮助作用。