安卓开发之探秘蓝牙隐藏API

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());

            }

 

        }

 

    }

 

}