（一）蓝牙之打开前准备工作

一.简单粗暴就直接上代码（有机会可以看源码就是这么幸福，我所看的是android 5.0的）

android开机时经过一系列启动进入到SystemServer.java，这里的一系列过程是

Init进程-》Zygote进程-》SystemServer进程-》各种应用进程具体自己去搜吧，这里就不讲！

SystemServer.java代码在frameworks/base/services/java/com/android/server/，现在我们来看看为什么讲这个呢？别忘了我写这个是有关蓝牙的，这里是开机是启动蓝牙服务的，

import android.bluetooth.BluetoothAdapter;

public final class SystemServer {
　　private void startOtherServices() {
　　　　BluetoothManagerService bluetooth = null;
　　　　boolean disableBluetooth = SystemProperties.getBoolean("config.disable_bluetooth", false);
       boolean isEmulator = SystemProperties.get("ro.kernel.qemu").equals("1");//这里暂时不深入看
    　　try {
          
            if (isEmulator) {
                Slog.i(TAG, "No Bluetooh Service (emulator)");
            } else if (mFactoryTestMode == FactoryTest.FACTORY_TEST_LOW_LEVEL) {
                Slog.i(TAG, "No Bluetooth Service (factory test)");
            } else if (!context.getPackageManager().hasSystemFeature
                       (PackageManager.FEATURE_BLUETOOTH)) {
                Slog.i(TAG, "No Bluetooth Service (Bluetooth Hardware Not Present)");
            } else if (disableBluetooth) {
                Slog.i(TAG, "Bluetooth Service disabled by config");
            } else {
                Slog.i(TAG, "Bluetooth Manager Service");
                bluetooth = new BluetoothManagerService(context);//这个才是我的目的，蓝牙管理服务在这里拉开序幕
                ServiceManager.addService(BluetoothAdapter.BLUETOOTH_MANAGER_SERVICE, bluetooth);//并添加到android的服务管理中
            }
        } catch (RuntimeException e) {
            Slog.e("System", "******************************************");
            Slog.e("System", "************ Failure starting core service", e);
        }
    }
 static final void startSystemUi(Context context) {
        Intent intent = new Intent();
        intent.setComponent(new ComponentName("com.android.systemui",
                    "com.android.systemui.SystemUIService"));
        //Slog.d(TAG, "Starting service: " + intent);
        context.startServiceAsUser(intent, UserHandle.OWNER);//这里调用上面的方法
    }
}    

　　接下来我们看一下BluetoothManagerService.java用来做什么？frameworks/base/services/core/java/com/android/server

private String mAddress;
private String mName;
private final ContentResolver mContentResolver;
private final RemoteCallbackList<IBluetoothManagerCallback> mCallbacks;
private final RemoteCallbackList<IBluetoothStateChangeCallback> mStateChangeCallbacks;
private IBluetooth mBluetooth;
private IBluetoothGatt mBluetoothGatt;
private boolean mBinding;
private boolean mUnbinding;
// used inside handler thread
private boolean mQuietEnable = false;
// configuarion from external IBinder call which is used to
// synchronize with broadcast receiver.
private boolean mQuietEnableExternal;
// configuarion from external IBinder call which is used to
// synchronize with broadcast receiver.
private boolean mEnableExternal;
// used inside handler thread
private boolean mEnable;
private int mState;
private final BluetoothHandler mHandler;
private int mErrorRecoveryRetryCounter;
private final int mSystemUiUid;

BluetoothManagerService(Context context) {

        mHandler = new BluetoothHandler(IoThread.get().getLooper());

        mContext = context;
        mBluetooth = null;
        mBinding = false;
        mUnbinding = false;
        mEnable = false;
        mState = BluetoothAdapter.STATE_OFF;
        mQuietEnableExternal = false;
        mEnableExternal = false;
        mAddress = null;
        mName = null;
        mErrorRecoveryRetryCounter = 0;
        mContentResolver = context.getContentResolver();
        mCallbacks = new RemoteCallbackList<IBluetoothManagerCallback>();
        mStateChangeCallbacks = new RemoteCallbackList<IBluetoothStateChangeCallback>();
        IntentFilter filter = new IntentFilter(Intent.ACTION_BOOT_COMPLETED);
        filter.addAction(BluetoothAdapter.ACTION_LOCAL_NAME_CHANGED);
        filter.addAction(Intent.ACTION_USER_SWITCHED);
        registerForAirplaneMode(filter);
        filter.setPriority(IntentFilter.SYSTEM_HIGH_PRIORITY);
        mContext.registerReceiver(mReceiver, filter);
        loadStoredNameAndAddress();
        if (isBluetoothPersistedStateOn()) {//看这里，android开机打开蓝牙
            mEnableExternal = true;
        }int sysUiUid = -1;
        try {
            sysUiUid = mContext.getPackageManager().getPackageUid("com.android.systemui",
                    UserHandle.USER_OWNER);
        } catch (PackageManager.NameNotFoundException e) {
            Log.wtf(TAG, "Unable to resolve SystemUI's UID.", e);
        }
        mSystemUiUid = sysUiUid;
    }

　　private final boolean isBluetoothPersistedStateOn() {
　　　　return Settings.Global.getInt(mContentResolver,
　　　　Settings.Global.BLUETOOTH_ON, 0) != BLUETOOTH_OFF;　　

　　}

这个类所做的事初始化与蓝牙相关的准备工作，蓝牙状态保存，蓝牙配置，蓝牙设备信息保存，供后面打开蓝牙使用;初始化完了会调用到app层

下一篇讲bluetooth enable