Android应用程序安装过程源代码分析（4）
Step 12. PackageManagerService.scanPackageLI
这个函数定义在frameworks/base/services/java/com/android/server/PackageManagerService.java文件中：
- class PackageManagerService extends IPackageManager.Stub {
- ......
- // Keys are String (package name), values are Package. This also serves
- // as the lock for the global state. Methods that must be called with
- // this lock held have the prefix "LP".
- final HashMap<String, PackageParser.Package> mPackages =
- new HashMap<String, PackageParser.Package>();
- ......
- // All available activities, for your resolving pleasure.
- final ActivityIntentResolver mActivities =
- new ActivityIntentResolver();
- // All available receivers, for your resolving pleasure.
- final ActivityIntentResolver mReceivers =
- new ActivityIntentResolver();
- // All available services, for your resolving pleasure.
- final ServiceIntentResolver mServices = new ServiceIntentResolver();
- // Keys are String (provider class name), values are Provider.
- final HashMap<ComponentName, PackageParser.Provider> mProvidersByComponent =
- new HashMap<ComponentName, PackageParser.Provider>();
- ......
- private PackageParser.Package scanPackageLI(PackageParser.Package pkg,
- int parseFlags, int scanMode, long currentTime) {
- ......
- synchronized (mPackages) {
- ......
- // Add the new setting to mPackages
- mPackages.put(pkg.applicationInfo.packageName, pkg);
- ......
- int N = pkg.providers.size();
- int i;
- for (i=0; i<N; i++) {
- PackageParser.Provider p = pkg.providers.get(i);
- p.info.processName = fixProcessName(pkg.applicationInfo.processName,
- p.info.processName, pkg.applicationInfo.uid);
- mProvidersByComponent.put(new ComponentName(p.info.packageName,
- p.info.name), p);
- ......
- }
- N = pkg.services.size();
- for (i=0; i<N; i++) {
- PackageParser.Service s = pkg.services.get(i);
- s.info.processName = fixProcessName(pkg.applicationInfo.processName,
- s.info.processName, pkg.applicationInfo.uid);
- mServices.addService(s);
- ......
- }
- N = pkg.receivers.size();
- r = null;
- for (i=0; i<N; i++) {
- PackageParser.Activity a = pkg.receivers.get(i);
- a.info.processName = fixProcessName(pkg.applicationInfo.processName,
- a.info.processName, pkg.applicationInfo.uid);
- mReceivers.addActivity(a, "receiver");
- ......
- }
- N = pkg.activities.size();
- for (i=0; i<N; i++) {
- PackageParser.Activity a = pkg.activities.get(i);
- a.info.processName = fixProcessName(pkg.applicationInfo.processName,
- a.info.processName, pkg.applicationInfo.uid);
- mActivities.addActivity(a, "activity");
- ......
- }
- ......
- }
- ......
- return pkg;
- }
- ......
- }
这个函数主要就是把前面解析应用程序得到的package、provider、service、receiver和activity等信息保存在PackageManagerService服务中了。
这样，在Android系统启动的时候安装应用程序的过程就介绍完了，但是，这些应用程序只是相当于在PackageManagerService服务注册好了，如果我们想要在Android桌面上看到这些应用程序，还需要有一个Home应用程序，负责从PackageManagerService服务中把这些安装好的应用程序取出来，并以友好的方式在桌面上展现出来，例如以快捷图标的形式。在Android系统中，负责把系统中已经安装的应用程序在桌面中展现出来的Home应用程序就是Launcher了，在下一篇文章中，我们将介绍Launcher是如何启动的以及它是如何从PackageManagerService服务中把系统中已经安装好的应用程序展现出来的，敬请期待。
本文转自 Luoshengyang 51CTO博客，原文链接：http://blog.51cto.com/shyluo/966524，如需转载请自行联系原作者
