爱华网
packagesappsPackageInstaller下InstallAppProgress.java调用installPackageWithVerificationAndEncryption()正式进入PackageManagerService.java。
PackageManagerService类中installPackageWithVerificationAndEncryption（）中有一个
final Message msg = mHandler.obtainMessage(INIT_COPY);
msg.obj = new InstallParams（）；
进入PackageHandler类的handleMessage（）方法，handleMessage（）会调用doHandleMessage（）方法，处理INIT_COPY消息，之后再handleMessage（），doHandleMessage（），处理MSC_BOUND。在处理MSC_BOUND消息时，会调用params.startCopy()方法，params是HandlerParams对象。startCopy（）方法中会调用handleStartCopy()方法，由此进入InstallParams的handleStartCopy（）方法。
handleStartCopy（）方法通常会直接进入
if (packageFile != null) {
// Remotecall to find out default install location
finalString packageFilePath = packageFile.getAbsolutePath();
pkgLite =mContainerService.getMinimalPackageInfo(packageFilePath, flags,
lowThreshold);
...}这段。重点看下pkgLite的初始化过程，即pkgLite =mContainerService.getMinimalPackageInfo(packageFilePath,flags，lowThreshold);mContainerService是IMediaContainerService对象，从IMediaContainerService类的起名就可以看出，这个类不可能有实例化对象，实例化的对象必然要有它的实现类来初始化，对应的类是DefaultContainerService.java,DefaultContainerService.java中getMinimalPackageInfo()调用PackageParser.parsePackageLite()得到PackageParser.PackageLite信息，从而初始化PackageInfoLiteret信息，其中PackageInfoLite的ret.recommendedInstallLocation信息尤其关键，它决定了应用安装的位置。详细看下ret.recommendedInstallLocation的获取过程，recommendAppInstallLocation()方法。recommendAppInstallLocation()这个函数根据packageInfo的installLocation和flags两个信息找出最佳安装位置，即PackageHelper.RECOMMEND_INSTALL_INTERNAL或PackageHelper.RECOMMEND_INSTALL_EXTERNAL。对应data区和SD卡区。一切正常，流程到if (ret == PackageManager.INSTALL_SUCCEEDED) { int loc =pkgLite.recommendedInstallLocation; Log.d(TAG,"[handleStartCopy]---gaoyh loc =" + loc); if (loc ==PackageHelper.RECOMMEND_FAILED_INVALID_LOCATION) { ret =PackageManager.INSTALL_FAILED_INVALID_INSTALL_LOCATION; } else if (loc ==PackageHelper.RECOMMEND_FAILED_ALREADY_EXISTS) { ret =PackageManager.INSTALL_FAILED_ALREADY_EXISTS; } else if (loc ==PackageHelper.RECOMMEND_FAILED_INSUFFICIENT_STORAGE) { ret =PackageManager.INSTALL_FAILED_INSUFFICIENT_STORAGE; 。。。}过程，通常情况下，package的flags值为0，那么位置选择为PackageHelper.RECOMMEND_INSTALL_INTERNAL，进入} else if (!onSd && !onInt) { //Override install location with flags if (loc ==PackageHelper.RECOMMEND_INSTALL_EXTERNAL) { // Set the flag to install onexternal media. flags |=PackageManager.INSTALL_EXTERNAL; flags &=~PackageManager.INSTALL_INTERNAL; } else{ // Make sure the flag forinstalling on external // media is unset flags |=PackageManager.INSTALL_INTERNAL; flags &=~PackageManager.INSTALL_EXTERNAL; Log.d(TAG,"[handleStartCopy]---gaoyh new flags =" + flags); } }中的else代码段，flags |=PackageManager.INSTALL_INTERNAL;flags &=~PackageManager.INSTALL_EXTERNAL;之后 final InstallArgs args= createInstallArgs(this);选择FileInstallArgs作为实现类，再往下跟，if (requiredUid != -1 &&isVerificationEnabled(flags)) {}这个通常是不走的，从而程序直接进入 ret = args.copyApk(mContainerService,true);过程。
