一、当Android设备中存在双卡时，移动网络默认为SIM卡1

完成这个需求有以下两个修改点：

   下面依旧是Android13 MTK平台，在MtkMultiSimSettingController.java的updateDefaults()方法中将移动网络设置为SIM1。

   除此之外，当存在双卡时，开机进入到Launcher界面时，首先就会出现一个对话框让我们去选择使用SIM卡1还是SIM卡2。所以当我们设置为默认SIM卡1之后，这个弹窗我们也需要去除掉。

1. 可以加入自己的判断，直接将autoFallbackEnabled重新赋值
2. 也可以在frameworks/base/core/res/res/values/config.xml，修改config_voice_data_sms_auto_fallback

二、下面是完整的代码路径和修改点

system/vendor/mediatek/proprietary/frameworks/opt/telephony/src/java/com/mediatek/internal/telephony/MtkMultiSimSettingController.java

    @Overrideprotected void updateDefaults() {//........省略多余代码.........boolean dataSelected = updateDefaultValue(mPrimarySubList,mSubController.getDefaultDataSubId(),(newValue ->{// The default mobile network is SIM 1int defaultSubId = mSubController.getDefaultDataSubId();if(defaultSubId == SubscriptionManager.INVALID_SUBSCRIPTION_ID){int subId1 = mSubController.getSubIdUsingPhoneId(0);if(subId1 == newValue){mSubController.setDefaultDataSubId(newValue);}}}));// The default mobile network is SIM 1// Update default voice subscription.if (DBG) log("[updateDefaultValues] Update default voice subscription");boolean voiceSelected = updateDefaultValue(mPrimarySubList,mSubController.getDefaultVoiceSubId(),(newValue -> mSubController.setDefaultVoiceSubId(newValue)));//........省略多余代码.........boolean autoFallbackEnabled = mContext.getResources().getBoolean(com.android.internal.R.bool.config_voice_data_sms_auto_fallback);// Based on config config_voice_data_sms_auto_fallback value choose voice/data/sms// preference auto selection logic or display notification for end used to// select voice/data/SMS preferences.// Removes the mobile network selection popup beginautoFallbackEnabled = true;// Removes the mobile network selection popup endif (!autoFallbackEnabled) {sendSubChangeNotificationIfNeeded(change, dataSelected, voiceSelected, smsSelected);} else {updateUserPreferences(mPrimarySubList, dataSelected, voiceSelected, smsSelected);}}

越想贴近事实，不明白的事情就越多。