一、为什么需要开启USB信任和ADB调试

问题1：原始的AOSP，如果通过USB连接设备以后，会弹窗提示用户选择连接模式：MTP，大容量磁盘，照片等模式；

问题2：USB连接设备以后，需要开启USB调试模式，才方便操作adb调试；

问题3：USB设备连接以后，电脑会弹窗是否信任设备，需要点击信任当前设备，否则设备连接不成功。

使用场景：我们是自己的系统，需要支持设备USB连接，以及adb远程调试(USB调试和TCP调回)，因此，系统需要默认支持USB连接，支持USB调试，默认信任连接的设备。

二、集成步骤

2.1 关闭USB调试弹窗

frameworks/base/packages/SystemUI/src/com/android/systemui/usb/UsbDebuggingActivity.java

@Overridepublic void onCreate(Bundle icicle) {
...(省略)
/**final AlertController.AlertParams ap = mAlertParams;ap.mTitle = getString(R.string.usb_debugging_title);ap.mMessage = getString(R.string.usb_debugging_message, fingerprints);ap.mPositiveButtonText = getString(R.string.usb_debugging_allow);ap.mNegativeButtonText = getString(android.R.string.cancel);ap.mPositiveButtonListener = this;ap.mNegativeButtonListener = this;// add "always allow" checkboxLayoutInflater inflater = LayoutInflater.from(ap.mContext);View checkbox = inflater.inflate(com.android.internal.R.layout.always_use_checkbox, null);mAlwaysAllow = (CheckBox)checkbox.findViewById(com.android.internal.R.id.alwaysUse);mAlwaysAllow.setText(getString(R.string.usb_debugging_always));ap.mView = checkbox;window.setCloseOnTouchOutside(false);setupAlert();**/notifyService(true,true);finish();
}

默认只要USB连接设备，默认就开启USB调试。关键方法是notifyService

/*** Notifies the ADB service as to whether the current ADB request should be allowed, and if* subsequent requests from this key should be allowed without user consent.** @param allow whether the connection should be allowed* @param alwaysAllow whether subsequent requests from this key should be allowed without user*                    consent*/private void notifyService(boolean allow, boolean alwaysAllow) {try {IBinder b = ServiceManager.getService(ADB_SERVICE);IAdbManager service = IAdbManager.Stub.asInterface(b);if (allow) {service.allowDebugging(alwaysAllow, mKey);} else {service.denyDebugging();}mServiceNotified = true;} catch (Exception e) {Log.e(TAG, "Unable to notify Usb service", e);}}

这个方法很简单，通过ADB服务，设置允许调试。

mKey是什么呢？就是设备指纹，即我们常说的设备SN。

2.2 授权ADB调试5555端口

device/qcom/lahaina/init.target.rc

    #Allow access to memory hotplug device attributeschown system system /sys/kernel/mem-offline/anon_migrate# ==== modify start===== zhouronghua open adb debug port 5555setprop service.adb.tcp.port 5555# ==== modify end=====

2.3 接收到USB连接默认开启USB调试

frameworks/base/packages/SystemUI/src/com/android/systemui/usb/UsbDebuggingActivity.java

在其中有监听USB连接和断开的广播接收器UsbDisconnectedReceiver，

private class UsbDisconnectedReceiver extends BroadcastReceiver {
...(省略)@Overridepublic void onReceive(Context content, Intent intent) {String action = intent.getAction();if (!UsbManager.ACTION_USB_STATE.equals(action)) {return;}// ====== modify begin ==========// fix: zhouronghua usb debug default auth// boolean connected = intent.getBooleanExtra(UsbManager.USB_CONNECTED, false);boolean connected = false;if (!connected) {Log.d(TAG, "USB disconnected, notifying service");// notifyService(false);mActivity.finish();}// open adb debuggingnotifyService(true, true);// =========== modify end ==========}}

开启USB调试，直接开启ADB调试即可，不需要单独开启USB调试，TCP调试。

2.4 USB授权默认信息

frameworks/base/packages/SystemUI/src/com/android/systemui/usb/UsbPermissionActivity.java

    @Overridepublic void onCreate(Bundle icicle) {...(省略)setupAlert();// ======= modify begin =========// fix: zhouronghua usb default trust devicesLog.d(TAG, "grant usb permission automatically");mPermissionGranted = true;finish();// ======= modify end =======}

默认同意授权USB连接。

 2.5 USB连接默认为MTP模式

USB管理器接收到USB连接监听

frameworks/base/services/usb/java/com/android/server/usb/UsbDeviceManager.java

USB连接默认采用MTP模式，且开启ADB调试。

        @Overridepublic void handleMessage(Message msg) {...(省略)if (mBootCompleted) {if (!mConnected &&            !hasMessages(MSG_ACCESSORY_MODE_ENTER_TIMEOUT)&& !hasMessages(MSG_FUNCTION_SWITCH_TIMEOUT)) {// restore defaults when USB is disconnected// fix: zhouronghua usb debug mode//if (!mScreenLocked//        && mScreenUnlockedFunctions != UsbManager.FUNCTION_NONE) {//    setScreenUnlockedFunctions();//} else {//setEnabledFunctions(UsbManager.FUNCTION_NONE, false);// USB connect enablesetEnabledFunctions(UsbManager.USB_FUNCTION_MTP, false);// adb enablesetAdbEnabled(true)//}}updateUsbFunctions();}protected void finishBoot() {if (mBootCompleted && mCurrentUsbFunctionsReceived && mSystemReady) {if (mPendingBootBroadcast) {updateUsbStateBroadcastIfNeeded(getAppliedFunctions(mCurrentFunctions));mPendingBootBroadcast = false;}// ========== modify start ===========//if (!mScreenLocked//        && mScreenUnlockedFunctions != UsbManager.FUNCTION_NONE) {//    setScreenUnlockedFunctions();//} else {//    setEnabledFunctions(UsbManager.FUNCTION_NONE, false);//}// fix: zhouronghua USB enablesetEnabledFunctions(UsbManager.USB_FUNCTION_MTP, false);// adb enablesetAdbEnabled(true);// ======== modify end =================

2.6 Release默认开启ADB调试

build/make/core/main.mk

build/make/core/main.mkifeq (true,$(strip $(enable_target_debugging)))# Target is more debuggable and adbd is on by defaultADDITIONAL_DEFAULT_PROPERTIES += ro.debuggable=1# Enable Dalvik lock contention logging.ADDITIONAL_BUILD_PROPERTIES += dalvik.vm.lockprof.threshold=500
else # !enable_target_debugging# Target is less debuggable and adbd is off by default# ==== mofify begin ===== zhouronghua fix: adb debug modeADDITIONAL_DEFAULT_PROPERTIES += ro.debuggable=1# ==== modify end ====
endif # !enable_target_debugging

在Release版本也允许进行ADB调试

2.7 post_process_props.py开启adb调试

build/make/tools/post_process_props.py

  # 1. 注释掉if prop.get("ro.debuggable") == "1"判断，Release也允许调试# ==== modify begin fix: zhoronghua open adb debug mode# if prop.get("ro.debuggable") == "1":# ==== modify end ====# 因为注释掉判断，判断体重的内容整体往前缩进val = prop.get("persist.sys.usb.config")if "adb" not in val:if val == "":val = "adb"else:val = val + ",adb"prop.put("persist.sys.usb.config", val)