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
@Override
public 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" checkbox
LayoutInflater 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 attributes
chown system system /sys/kernel/mem-offline/anon_migrate
# ==== modify start===== zhouronghua open adb debug port 5555
setprop 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)
@Override
public 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 debugging
notifyService(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
@Override
public void onCreate(Bundle icicle) {
...(省略)
setupAlert();
// ======= modify begin =========
// fix: zhouronghua usb default trust devices
Log.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。
@Override
public 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 enable
setEnabledFunctions(UsbManager.USB_FUNCTION_MTP, false);
// adb enable
setAdbEnabled(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 enable
setEnabledFunctions(UsbManager.USB_FUNCTION_MTP, false);
// adb enable
setAdbEnabled(true);
// ======== modify end =================
2.6 Release默认开启ADB调试
build/make/core/main.mk
build/make/core/main.mk
ifeq (true,$(strip $(enable_target_debugging)))
# Target is more debuggable and adbd is on by default
ADDITIONAL_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 mode
ADDITIONAL_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)