Android提高第十三篇之探秘蓝牙隐藏API

http://blog.csdn.net/hellogv/archive/2010/11/29/6042091.aspx
       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:layout_height="wrap_content" android:id="@+id/btnSearch"  
            android:text="Search" android:layout_width="160dip"></Button>  
        <Button android:layout_height="wrap_content"  
            android:layout_width="160dip" android:text="Show" android:id="@+id/btnShow"></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());  
            }  
  
        }  
  
    }  
  
  
}