Android 10.0 USB连接模式默认选为MTP

原创已于 2022-11-10 15:27:34 修改 · 2.3k 阅读

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文章标签：

#android #java #usb

于 2021-03-10 20:01:59 首次发布

本文解析了Android系统中USB模式的设置逻辑，特别是在设备解锁后如何自动切换到MTP模式的过程。通过源代码分析，详细介绍了`UsbDeviceManager`类中的`setScreenUnlockedFunctions`和`finishBoot`方法实现细节。

alps\frameworks\base\services\usb\java\com\android\server\usb\UsbDeviceManager.java

        private void setScreenUnlockedFunctions() {
         //   setEnabledFunctions(mScreenUnlockedFunctions, false);
	      setEnabledFunctions(UsbManager.FUNCTION_MTP, false);
        }//将解锁后usb模式改为MTP，默认是UsbManager.FUNCTION_NONE

        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, false);
                }
                if (mCurrentAccessory != null) {
                    mUsbDeviceManager.getCurrentSettings().accessoryAttached(mCurrentAccessory);
                }

                updateUsbNotification(false);
                updateAdbNotification(false);
                updateUsbFunctions();
            }
        }