Android提高之蓝牙隐藏API探秘
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): 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();
}
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：
<?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>
