安卓开发之探秘蓝牙隐藏API_移动开发_编程开发_程序员俱乐部

上次讲解Android的蓝牙基本用法，这次讲得深入些，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): createBond
11-29 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): removeBond
11-29 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(); }

PS : 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：

main.xml源码如下：

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:orientation="vertical"     android:layout_width="fill_parent"     android:layout_height="fill_parent">     <LinearLayout         android:id="@+id/LinearLayout01"         android:layout_height="wrap_content"         android:layout_width="fill_parent">         <Button             android:id="@+id/btnSearch"             android:layout_width="160dip"             android:layout_height="wrap_content"             android:text="Search">         </Button>         <Button             android:id="@+id/btnShow"             android:layout_height="wrap_content"             android:layout_width="160dip"             android:text="Show"         </Button>     </LinearLayout>     <LinearLayout         android:id="@+id/LinearLayout02"         android:layout_width="wrap_content"         android:layout_height="wrap_content">     </LinearLayout>     <ListView         android:id="@+id/ListView01"         android:layout_width="fill_parent"         android:layout_height="fill_parent">     </ListView> </LinearLayout>

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<String> adtDevices;     List<String> lstDevices = new ArrayList<String>();     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<String>(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());             }           }       }   }