Android 8.1 USB连接模式默认为MTP

Android 8.1 USB连接模式默认为MTP

最近收到项目需求，要求设备默认的USB连接模式为MTP，具体修改参照如下：

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

        public void handleMessage(Message msg) {
            switch (msg.what) {
                case MSG_UPDATE_STATE:
                    mConnected = (msg.arg1 == 1);
                    mConfigured = (msg.arg2 == 1);

                    updateUsbNotification(false);
                    updateAdbNotification(false);
                    if (mBootCompleted) {
                        updateUsbStateBroadcastIfNeeded(getAppliedFunctions(mCurrentFunctions));
                    }
                    if ((mCurrentFunctions & UsbManager.FUNCTION_ACCESSORY) != 0) {
                        updateCurrentAccessory();
                    }
                    if (mBootCompleted) {
                        if (!mConnected && !hasMessages(MSG_ACCESSORY_MODE_ENTER_TIMEOUT)
                                && !hasMessages(MSG_FUNCTION_SWITCH_TIMEOUT)) {
                            // restore defaults when USB is disconnected
                            if (!mScreenLocked
                                    && mScreenUnlockedFunctions != UsbManager.FUNCTION_NONE) {
                                setScreenUnlockedFunctions();
                            } else {
-                                setEnabledFunctions(UsbManager.FUNCTION_NONE, false);
+                                setEnabledFunctions(UsbManager.FUNCTION_MTP, true);
                            }
                        }

        protected void finishBoot() {
            if (mBootCompleted && mCurrentUsbFunctionsReceived && mSystemReady) {
                if (mPendingBootBroadcast) {
                    updateUsbStateBroadcastIfNeeded(getAppliedFunctions(mCurrentFunctions));
                    mPendingBootBroadcast = false;
                }
                if (!mScreenLocked
                        && mScreenUnlockedFunctions != UsbManager.FUNCTION_NONE) {
                    setScreenUnlockedFunctions();
                } else {
-                    setEnabledFunctions(UsbManager.FUNCTION_NONE, false);
+                    setEnabledFunctions(UsbManager.FUNCTION_MTP, true);
                }

重新编译验证，修改生效，设备默认的USB连接模式已设为MTP