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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 = http://www.mamicode.com/(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 = http://www.mamicode.com/(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:

程序运行效果图

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 = http://www.mamicode.com/(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 = http://www.mamicode.com/(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());
            }
 
        }
 
    }
 
}