在高通平台上，更换SIM卡后开机会有一个提示信息。
在双卡项目上遇到了这样一个问题，当用户只插入一张卡2时，开机SIM变更提示显示为卡1。
如图所示：
这里主要是分析为什么这个SIM卡信息会显示错误，所以不赘述弹出过程，直奔主题：
vendor/qcom/proprietary/qrdplus/Extension/apps/PhoneFeatures/src/com/android/phonefeature/simdetector/MSimStateService.java
protected void alertSIMChanged() { mSimDetectorApp.onSimChangedNotified(); saveSubscriptions(); SpannableStringBuilder spanStrBuilderSIMInfo = getSIMInfo(); // BEGIN: Modified by Tony at 2014-01-21 for 0024804 AlertDialog dialog = null; AlertDialog.Builder builder = new AlertDialog.Builder(this); // AlertDialog dialog = builder.setTitle(R.string.sim_info).setMessage(spanStrBuilderSIMInfo) // .setNegativeButton(R.string.close, this) // .setPositiveButton(R.string.change, this).create(); if ("msm8610_t7_j930_cu".equals(SystemProperties.get("ro.product.name"))) { dialog = builder.setTitle(R.string.config_sub_title).setMessage(R.string.new_cards_available) .setNegativeButton(R.string.close, this) .setPositiveButton(R.string.ok, this).create(); } else { dialog = builder.setTitle(R.string.sim_info).setMessage(spanStrBuilderSIMInfo) .setNegativeButton(R.string.close, this) .setPositiveButton(R.string.change, this).create(); } // END: Modified by Tony at 2014-01-21 dialog.getWindow().setType( WindowManager.LayoutParams.TYPE_KEYGUARD_DIALOG); dialog.show(); }alertSIMChanged()这个方法就是弹出提示框的方法，我们主要关注的是它的信息，来看getSIMInfo()。
private SpannableStringBuilder getSIMInfo() { final TypedArray icons = this.getResources().obtainTypedArray( com.android.internal.R.array.sim_icons); ConnectivityManager connService = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE); boolean mobileDataEnabled = connService.getMobileDataEnabled(); String mobileDataState = mobileDataEnabled ? getString(R.string.mobile_data_on) : getString(R.string.mobile_data_off); final int dataSub = MSimPhoneFactory.getDataSubscription(); String html = getString(R.string.new_sim_detected) + "<br>" + getString(R.string.mobile_data) + getString(R.string.slot) + (dataSub + 1) + " <img src='data'/> " + getString(R.string.carrier_name) + "<br>" + getString(R.string.mobile_data) + mobileDataState; SpannableStringBuilder spannableStringBuilder = (SpannableStringBuilder) Html.fromHtml( html, new ImageGetter() { public Drawable getDrawable(String source) { Drawable drawable = null; if (source.equals(DATA_OPTION)) { drawable = icons.getDrawable(dataSub); drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight()); } return drawable; } }, null); return spannableStringBuilder; }String类型的html变量就是将要显示的内容。
final int dataSub = MSimPhoneFactory.getDataSubscription();
dataSub + 1 就是显示的（卡）1或者2 （加1是因为代码中获取到的卡1为0，卡2为1）
那么就是这里获取的值出错了，继续往下跟。
frameworks/opt/telephony-msim/frameworks/src/com/codeaurora/internal/telephony/MSimPhoneFactory.java
public static int getDataSubscription() { int subscription = 0; try { subscription = Settings.Global.getInt(sContext.getContentResolver(), Settings.Global.MULTI_SIM_DATA_CALL_SUBSCRIPTION); } catch (SettingNotFoundException snfe) { Rlog.e(LOG_TAG, "Settings Exception Reading Dual Sim Data Call Values"); } if (subscription < 0 || subscription >= MSimTelephonyManager.getDefault().getPhoneCount()) { Rlog.i(LOG_TAG, "Subscription is invalid..." + subscription + " Set to 0"); subscription = 0; setDataSubscription(subscription); } return subscription; }也就是说subscription始终返回的是0，仔细一看这个逻辑就有问题了。
如果subscription = Settings.Global.getInt(sContext.getContentResolver(), Settings.Global.MULTI_SIM_DATA_CALL_SUBSCRIPTION);获取到的是0，或者下面的这个判断可以通过的话那么将始终返回0。
但是卡1（0代表卡1）不一定是可用的（没有插卡），这种返回将导致开篇指出的提示信息有误。
提供一种解决思路：
public static int getDataSubscription() { int subscription = 0; try { subscription = Settings.Global.getInt(sContext.getContentResolver(), Settings.Global.MULTI_SIM_DATA_CALL_SUBSCRIPTION); } catch (SettingNotFoundException snfe) { Rlog.e(LOG_TAG, "Settings Exception Reading Dual Sim Data Call Values"); } // BEGIN: Modified by Tony at 2014-03-22 for 0028503 //if (subscription < 0 || subscription >= MSimTelephonyManager.getDefault().getPhoneCount()) { // Rlog.i(LOG_TAG, "Subscription is invalid..." + subscription + " Set to 0"); // subscription = 0; // setDataSubscription(subscription); //} boolean isHasSUB1 = MSimTelephonyManager.getDefault().hasIccCard(MSimConstants.SUB1); boolean isHasSUB2 = MSimTelephonyManager.getDefault().hasIccCard(MSimConstants.SUB2); boolean isHasDataSubscription = MSimTelephonyManager.getDefault().hasIccCard(subscription); if (subscription < 0 || subscription >= MSimTelephonyManager.getDefault().getPhoneCount() || !isHasDataSubscription) { int currentSubscription = 0; if (isHasSUB1) { currentSubscription = MSimConstants.SUB1; } else if (isHasSUB2) { currentSubscription = MSimConstants.SUB2; } if (currentSubscription != subscription) { subscription = currentSubscription; setDataSubscription(subscription); } } // END: Modified by Tony at 2014-03-22 return subscription; }对卡槽1、卡槽2和获取到的subscription进行判断是否插入SIM卡，如果获取到的subscription卡槽没有插入SIM卡（还有其他两个条件）则对其进行重置操作。
如果卡槽1插入了SIM卡则优先设置使用卡1数据流量并返回，若卡槽1未插卡，则判断卡2，都没有插卡则默认返回卡1（没关系的，都不插卡不会有弹出提示框）。
仅供参考，如有更好的思路请留言。相互学习，谢谢。