Android应用程序安装过程解析
在Android系统中，apk安装文件是会被保存起来的，默认情况下，用户安装的apk首先会被拷贝到 /data/app 目录下。
/data/app目录是用户有权限访问的目录，在安装apk的时候会自动选择该目录存放用户安装的文件，而系统出厂的apk文件则被放到了 /system 分区下,包括 /system/app，/system/vendor/app，以及 /system/priv-app 等等，该分区只有Root权限的用户才能访问，这也就是为什么在没有Root手机之前，我们无法删除系统出厂的app的原因了。
为了加快app的启动速度，apk在安装的时候，会首先将app的可执行文件（dex）拷贝到 /data/dalvik-cache 目录，缓存起来。
然后，在/data/data/目录下创建应用程序的数据目录（以应用的包名命名），存放应用的相关数据，如数据库、xml文件、cache、二进制的so动态库等等。
Android系统中，也有一个类似注册表的东西，用来记录当前所有安装的应用的基本信息，每次系统安装或者卸载了任何apk文件，都会更新这个文件。这个文件位于如下目录：
/data/system/packages.xml
系统在安装apk的过程中，会解析apk的AndroidManifinest.xml文件，提取出这个apk的重要信息写入到packages.xml文件中，这些信息包括：权限、应用包名、APK的安装位置、版本、userID等等。
由此，我们就知道了为啥一些应用市场和软件管理类的app能够很清楚地知道当前手机所安装的所有的app，以及这些app的详细信息了。
另外一件事就是Linux的用户Id和用户组Id，以便他可以获得合适的运行权限。
以上这些都是由PackageServiceManager完成的，下面我们会重点介绍PackageServiceManager。
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
Android系统在启动的过程中，会启动一个应用程序管理服务PackageManagerService，这个服务负责扫描系统中特定的目录，找到里面的应用程序文件，即以Apk为后缀的文件，然后对这些文件进解析，得到应用程序的相关信息。
应用程序管理服务PackageManagerService安装应用程序的过程，其实就是解析析应用程序配置文件AndroidManifest.xml的过程，并从里面得到得到应用程序的相关信息，例如得到应用程序的组件Activity、Service、Broadcast Receiver和Content Provider等信息，有了这些信息后，通过ActivityManagerService这个服务，我们就可以在系统中正常地使用这些应用程序了。
应用程序管理服务PackageManagerService是系统启动的时候由SystemServer组件启动的，启后它就会执行应用程序安装的过程，因此，本文将从SystemServer启动PackageManagerService服务的过程开始分析系统中的应用程序安装的过程。
安装过程：
复制APK安装包到data/app目录下，解压并扫描安装包，把dex文件(Dalvik字节码)保存到dalvik-cache目录，并data/data目录下创建对应的应用数据目录。
卸载过程：
删除安装过程中在上述三个目录下创建的文件及目录。
PackageManagerService处理各种应用的安装，卸载，管理等工作，开机时由systemServer启动此服务
在创建这个PackageManagerService服务实例时，会在PackageManagerService类的构造函数中开始执行安装应用程序的过程：
恢复上一次程序的安装信息是通过PackageManagerService 的成员变量mSetting的readLP()来实现的，恢复信息之后就开始扫描和安装app了。
#扫描安装app ##Step 8. PackageManagerService.scanDirLI 这个函数定义在frameworks/base/services/java/com/android/server/PackageManagerService.java文件中： [java] view plain copy class PackageManagerService extends IPackageManager.Stub { ...... private void scanDirLI(File dir, int flags, int scanMode, long currentTime) { String[] files = dir.list(); ...... int i; for (i=0; i<files.length; i++) { File file = new File(dir, files[i]); if (!isPackageFilename(files[i])) { // Ignore entries which are not apk's continue; } PackageParser.Package pkg = scanPackageLI(file, flags|PackageParser.PARSE_MUST_BE_APK, scanMode, currentTime); // Don't mess around with apps in system partition. if (pkg == null && (flags & PackageParser.PARSE_IS_SYSTEM) == 0 && mLastScanError == PackageManager.INSTALL_FAILED_INVALID_APK) { // Delete the apk Slog.w(TAG, "Cleaning up failed install of " + file); file.delete(); } } } ...... } 对于目录中的每一个文件，如果是以后Apk作为后缀名，那么就调用scanPackageLI函数来对它进行解析和安装。 ##Step 9. PackageManagerService.scanPackageLI 这个函数定义在frameworks/base/services/java/com/android/server/PackageManagerService.java文件中： [java] view plain copy 在CODE上查看代码片派生到我的代码片 class PackageManagerService extends IPackageManager.Stub { ...... private PackageParser.Package scanPackageLI(File scanFile, int parseFlags, int scanMode, long currentTime) { ...... String scanPath = scanFile.getPath(); parseFlags |= mDefParseFlags; PackageParser pp = new PackageParser(scanPath); ...... final PackageParser.Package pkg = pp.parsePackage(scanFile, scanPath, mMetrics, parseFlags); ...... return scanPackageLI(pkg, parseFlags, scanMode | SCAN_UPDATE_SIGNATURE, currentTime); } ...... } 这个函数首先会为这个Apk文件创建一个PackageParser实例，接着调用这个实例的parsePackage函数来对这个Apk文件进行解析。这个函数最后还会调用另外一个版本的scanPackageLI函数把来解析后得到的应用程序信息保存在PackageManagerService中。 ## Step 10. PackageParser.parsePackage 这个函数定义在frameworks/base/core/java/android/content/pm/PackageParser.java文件中： [java] view plain copy 在CODE上查看代码片派生到我的代码片 public class PackageParser { ...... public Package parsePackage(File sourceFile, String destCodePath, DisplayMetrics metrics, int flags) { ...... mArchiveSourcePath = sourceFile.getPath(); ...... XmlResourceParser parser = null; AssetManager assmgr = null; boolean assetError = true; try { assmgr = new AssetManager(); int cookie = assmgr.addAssetPath(mArchiveSourcePath); if(cookie != 0) { parser = assmgr.openXmlResourceParser(cookie, "AndroidManifest.xml"); assetError = false; } else { ...... } } catch (Exception e) { ...... } ...... String[] errorText = new String[1]; Package pkg = null; Exception errorException = null; try { // XXXX todo: need to figure out correct configuration. Resources res = new Resources(assmgr, metrics, null); pkg = parsePackage(res, parser, flags, errorText); } catch (Exception e) { ...... } ...... parser.close(); assmgr.close(); // Set code and resource paths pkg.mPath = destCodePath; pkg.mScanPath = mArchiveSourcePath; //pkg.applicationInfo.sourceDir = destCodePath; //pkg.applicationInfo.publicSourceDir = destRes; pkg.mSignatures = null; return pkg; } ...... } 每一个Apk文件都是一个归档文件，它里面包含了Android应用程序的配置文件AndroidManifest.xml，这里主要就是要对这个配置文件就行解析了，从Apk归档文件中得到这个配置文件后，就调用另一外版本的parsePackage函数对这个应用程序进行解析了：[java] view plain copy 在CODE上查看代码片派生到我的代码片
public class PackageParser { ...... private Package parsePackage( Resources res, XmlResourceParser parser, int flags, String[] outError) throws XmlPullParserException, IOException { ...... String pkgName = parsePackageName(parser, attrs, flags, outError); ...... final Package pkg = new Package(pkgName); ...... int type; ...... TypedArray sa = res.obtainAttributes(attrs, com.android.internal.R.styleable.AndroidManifest); ...... while ((type=parser.next()) != parser.END_DOCUMENT && (type != parser.END_TAG || parser.getDepth() > outerDepth)) { if (type == parser.END_TAG || type == parser.TEXT) { continue; } String tagName = parser.getName(); if (tagName.equals("application")) { ...... if (!parseApplication(pkg, res, parser, attrs, flags, outError)) { return null; } } else if (tagName.equals("permission-group")) { ...... } else if (tagName.equals("permission")) { ...... } else if (tagName.equals("permission-tree")) { ...... } else if (tagName.equals("uses-permission")) { ...... } else if (tagName.equals("uses-configuration")) { ...... } else if (tagName.equals("uses-feature")) { ...... } else if (tagName.equals("uses-sdk")) { ...... } else if (tagName.equals("supports-screens")) { ...... } else if (tagName.equals("protected-broadcast")) { ...... } else if (tagName.equals("instrumentation")) { ...... } else if (tagName.equals("original-package")) { ...... } else if (tagName.equals("adopt-permissions")) { ...... } else if (tagName.equals("uses-gl-texture")) { ...... } else if (tagName.equals("compatible-screens")) { ...... } else if (tagName.equals("eat-comment")) { ...... } else if (RIGID_PARSER) { ...... } else { ...... } } ...... return pkg; } ...... } 这里就是对AndroidManifest.xml文件中的各个标签进行解析了，各个标签的含义可以参考官方文档http://developer.android.com/guide/topics/manifest/manifest-intro.html，这里我们只简单看一下application标签的解析，这是通过调用parseApplication函数来进行的。 ## Step 11. PackageParser.parseApplication 这个函数定义在frameworks/base/core/java/android/content/pm/PackageParser.java文件中： [java] view plain copy 在CODE上查看代码片派生到我的代码片 public class PackageParser { ...... private boolean parseApplication(Package owner, Resources res, XmlPullParser parser, AttributeSet attrs, int flags, String[] outError) throws XmlPullParserException, IOException { final ApplicationInfo ai = owner.applicationInfo; final String pkgName = owner.applicationInfo.packageName; TypedArray sa = res.obtainAttributes(attrs, com.android.internal.R.styleable.AndroidManifestApplication); ...... int type; while ((type=parser.next()) != parser.END_DOCUMENT && (type != parser.END_TAG || parser.getDepth() > innerDepth)) { if (type == parser.END_TAG || type == parser.TEXT) { continue; } String tagName = parser.getName(); if (tagName.equals("activity")) { Activity a = parseActivity(owner, res, parser, attrs, flags, outError, false); ...... owner.activities.add(a); } else if (tagName.equals("receiver")) { Activity a = parseActivity(owner, res, parser, attrs, flags, outError, true); ...... owner.receivers.add(a); } else if (tagName.equals("service")) { Service s = parseService(owner, res, parser, attrs, flags, outError); ...... owner.services.add(s); } else if (tagName.equals("provider")) { Provider p = parseProvider(owner, res, parser, attrs, flags, outError); ...... owner.providers.add(p); } else if (tagName.equals("activity-alias")) { Activity a = parseActivityAlias(owner, res, parser, attrs, flags, outError); ...... owner.activities.add(a); } else if (parser.getName().equals("meta-data")) { ...... } else if (tagName.equals("uses-library")) { ...... } else if (tagName.equals("uses-package")) { ...... } else { ...... } } return true; } ...... } 这里就是对AndroidManifest.xml文件中的application标签进行解析了，我们常用到的标签就有activity、service、receiver和provider，各个标签的含义可以参考官方文档http://developer.android.com/guide/topics/manifest/manifest-intro.html。 这里解析完成后，一层层返回到Step 9中，调用另一个版本的scanPackageLI函数把来解析后得到的应用程序信息保存下来。 ##Step 12. PackageManagerService.scanPackageLI 这个函数定义在frameworks/base/services/java/com/android/server/PackageManagerService.java文件中： [java] view plain copy 在CODE上查看代码片派生到我的代码片 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。
1)从apk, xml中载入pacakge信息, 存储到内部成员变量中, 用于后面的查找. 关键的方法是scanPackageLI(). 2)各种查询操作, 包括query Intent操作. 3)install package和delete package的操作. 还有后面的关键方法是installPackageLI().
下载完成后，会自动调用Packagemanager的安装方法installPackage（）
“`
/* Called when a downloaded package installation has been confirmed by the user */
由英文注释可见PackageManagerService类的installPackage（）函数为安装程序入口。[java] view plain copy public void installPackage( final Uri packageURI, final IPackageInstallObserver observer, final int flags, final String installerPackageName) { mContext.enforceCallingOrSelfPermission( android.Manifest.permission.INSTALL_PACKAGES, null); Message msg = mHandler.obtainMessage(INIT_COPY); msg.obj = new InstallParams(packageURI, observer, flags, installerPackageName); mHandler.sendMessage(msg); }
其中是通过PackageHandler的实例mhandler.sendMessage（msg）把信息发给继承Handler的类HandleMessage()方法[java] view plain copy class PackageHandler extends Handler{
*******省略若干********** public void handleMessage(Message msg) { try { doHandleMessage(msg); } finally { Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND); } } ********省略若干************ }
把信息发给doHandleMessage()方法,方法中用switch（）语句进行判定传来Message[java] view plain copy void doHandleMessage(Message msg) { switch (msg.what) {
case INIT_COPY: { if (DEBUG_SD_INSTALL) Log.i(TAG, "init_copy"); HandlerParams params = (HandlerParams) msg.obj; int idx = mPendingInstalls.size(); if (DEBUG_SD_INSTALL) Log.i(TAG, "idx=" + idx); // If a bind was already initiated we dont really // need to do anything. The pending install // will be processed later on. if (!mBound) { // If this is the only one pending we might // have to bind to the service again. if (!connectToService()) { Slog.e(TAG, "Failed to bind to media container service"); params.serviceError(); return; } else { // Once we bind to the service, the first // pending request will be processed. mPendingInstalls.add(idx, params); } } else { mPendingInstalls.add(idx, params); // Already bound to the service. Just make // sure we trigger off processing the first request. if (idx == 0) { mHandler.sendEmptyMessage(MCS_BOUND); } } break; } case MCS_BOUND: { if (DEBUG_SD_INSTALL) Log.i(TAG, "mcs_bound"); if (msg.obj != null) { mContainerService = (IMediaContainerService) msg.obj; } if (mContainerService == null) { // Something seriously wrong. Bail out Slog.e(TAG, "Cannot bind to media container service"); for (HandlerParams params : mPendingInstalls) { mPendingInstalls.remove(0); // Indicate service bind error params.serviceError(); } mPendingInstalls.clear(); } else if (mPendingInstalls.size() > 0) { HandlerParams params = mPendingInstalls.get(0); if (params != null) { params.startCopy(); } } else { // Should never happen ideally. Slog.w(TAG, "Empty queue"); } break; } ****************省略若干**********************} }
public final boolean sendMessage (Message msg) public final boolean sendEmptyMessage (int what) 两者参数有别。 然后调用抽象类HandlerParams中的一个startCopy（）方法 abstract class HandlerParams { final void startCopy() { ***************若干if语句判定否这打回handler消息******* handleReturnCode(); } } handleReturnCode（）复写了两次其中有一次是删除时要调用的，只列出安装调用的一个方法[java] view plain copy @Override void handleReturnCode() { // If mArgs is null, then MCS couldn’t be reached. When it // reconnects, it will try again to install. At that point, this // will succeed. if (mArgs != null) { processPendingInstall(mArgs, mRet); } }
这时可以清楚的看见 processPendingInstall（）被调用。 其中run（）方法如下 [java] view plain copy run(){ synchronized (mInstallLock) { ************省略***************** installPackageLI(args, true, res); } } instaPacakgeLI（）args,res参数分析 ----------------------------------------------------------------------------------------- //InstallArgs 是在PackageService定义的static abstract class InstallArgs 静态抽象类。[java] view plain copy static abstract class InstallArgs {
其中定义了flag标志，packageURL，创建文件，拷贝apk，修改包名称， 还有一些删除文件的清理，释放存储函数。 *********************************************************** } class PackageInstalledInfo { String name; int uid; PackageParser.Package pkg; int returnCode; PackageRemovedInfo removedInfo; }
[java] view plain copy private void installPackageLI(InstallArgs args, boolean newInstall, PackageInstalledInfo res) { int pFlags = args.flags; String installerPackageName = args.installerPackageName; File tmpPackageFile = new File(args.getCodePath()); boolean forwardLocked = ((pFlags & PackageManager.INSTALL_FORWARD_LOCK) != 0); boolean onSd = ((pFlags & PackageManager.INSTALL_EXTERNAL) != 0); boolean replace = false; int scanMode = (onSd ? 0 : SCAN_MONITOR) | SCAN_FORCE_DEX | SCAN_UPDATE_SIGNATURE | (newInstall ? SCAN_NEW_INSTALL : 0); // Result object to be returned res.returnCode = PackageManager.INSTALL_SUCCEEDED; // Retrieve PackageSettings and parse package int parseFlags = PackageParser.PARSE_CHATTY | (forwardLocked ? PackageParser.PARSE_FORWARD_LOCK : 0) | (onSd ? PackageParser.PARSE_ON_SDCARD : 0); parseFlags |= mDefParseFlags; PackageParser pp = new PackageParser(tmpPackageFile.getPath()); pp.setSeparateProcesses(mSeparateProcesses); final PackageParser.Package pkg = pp.parsePackage(tmpPackageFile, null, mMetrics, parseFlags); if (pkg == null) { res.returnCode = pp.getParseError(); return; } String pkgName = res.name = pkg.packageName; if ((pkg.applicationInfo.flags&ApplicationInfo.FLAG_TEST_ONLY) != 0) { if ((pFlags&PackageManager.INSTALL_ALLOW_TEST) == 0) { res.returnCode = PackageManager.INSTALL_FAILED_TEST_ONLY; return; } } if (GET_CERTIFICATES && !pp.collectCertificates(pkg, parseFlags)) { res.returnCode = pp.getParseError(); return; } // Get rid of all references to package scan path via parser. pp = null; String oldCodePath = null; boolean systemApp = false; synchronized (mPackages) { // Check if installing already existing package if ((pFlags&PackageManager.INSTALL_REPLACE_EXISTING) != 0) { String oldName = mSettings.mRenamedPackages.get(pkgName); if (pkg.mOriginalPackages != null && pkg.mOriginalPackages.contains(oldName) && mPackages.containsKey(oldName)) { // This package is derived from an original package, // and this device has been updating from that original // name. We must continue using the original name, so // rename the new package here. pkg.setPackageName(oldName); pkgName = pkg.packageName; replace = true; } else if (mPackages.containsKey(pkgName)) { // This package, under its official name, already exists // on the device; we should replace it. replace = true; } } PackageSetting ps = mSettings.mPackages.get(pkgName); if (ps != null) { oldCodePath = mSettings.mPackages.get(pkgName).codePathString; if (ps.pkg != null && ps.pkg.applicationInfo != null) { systemApp = (ps.pkg.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0; } } } if (systemApp && onSd) { // Disable updates to system apps on sdcard Slog.w(TAG, “Cannot install updates to system apps on sdcard”); res.returnCode = PackageManager.INSTALL_FAILED_INVALID_INSTALL_LOCATION; return; } if (!args.doRename(res.returnCode, pkgName, oldCodePath)) { res.returnCode = PackageManager.INSTALL_FAILED_INSUFFICIENT_STORAGE; return; } // Set application objects path explicitly after the rename setApplicationInfoPaths(pkg, args.getCodePath(), args.getResourcePath()); pkg.applicationInfo.nativeLibraryDir = args.getNativeLibraryPath(); if (replace) { replacePackageLI(pkg, parseFlags, scanMode, installerPackageName, res); } else { installNewPackageLI(pkg, parseFlags, scanMode, installerPackageName,res); } }
最后判断如果以前不存在那么调用installNewPackageLI(）[java] view plain copy private void installNewPackageLI(PackageParser.Package pkg, int parseFlags,int scanMode, String installerPackageName, PackageInstalledInfo res) { *************省略若干*************************************** PackageParser.Package newPackage = scanPackageLI(pkg, parseFlags, scanMode, System.currentTimeMillis()); *************省略若干**************************************** }
最后终于回到了和开机安装一样的地方.与开机方式安装调用统一方法。 #(3)从ADB工具安装 其入口函数源文件为pm.java (源文件路径：android\frameworks\base\cmds\pm\src\com\android\commands\pm\pm.java) 其中\system\framework\pm.jar 包管理库 包管理脚本 \system\bin\pm 解析 showUsage就是使用方法[java] view plain copy private static void showUsage() { System.err.println(“usage: pm [list|path|install|uninstall]”); System.err.println(” pm list packages [-f]”); System.err.println(” pm list permission-groups”); System.err.println(” pm list permissions [-g] [-f] [-d] [-u] [GROUP]”); System.err.println(” pm list instrumentation [-f] [TARGET-PACKAGE]”); System.err.println(” pm list features”); System.err.println(” pm path PACKAGE”); System.err.println(” pm install [-l] [-r] [-t] [-i INSTALLER_PACKAGE_NAME] [-s] [-f] PATH”); System.err.println(” pm uninstall [-k] PACKAGE”); System.err.println(” pm enable PACKAGE_OR_COMPONENT”); System.err.println(” pm disable PACKAGE_OR_COMPONENT”); System.err.println(” pm setInstallLocation [0/auto] [1/internal] [2/external]”); ************省略**************** }
安装时候会调用 runInstall（）方法[java] view plain copy private void runInstall() { int installFlags = 0; String installerPackageName = null; String opt; while ((opt=nextOption()) != null) { if (opt.equals(“-l”)) { installFlags |= PackageManager.INSTALL_FORWARD_LOCK; } else if (opt.equals(“-r”)) { installFlags |= PackageManager.INSTALL_REPLACE_EXISTING; } else if (opt.equals(“-i”)) { installerPackageName = nextOptionData(); if (installerPackageName == null) { System.err.println(“Error: no value specified for -i”); showUsage(); return; } } else if (opt.equals(“-t”)) { installFlags |= PackageManager.INSTALL_ALLOW_TEST; } else if (opt.equals(“-s”)) { // Override if -s option is specified. installFlags |= PackageManager.INSTALL_EXTERNAL; } else if (opt.equals(“-f”)) { // Override if -s option is specified. installFlags |= PackageManager.INSTALL_INTERNAL; } else { System.err.println(“Error: Unknown option: ” + opt); showUsage(); return; } } String apkFilePath = nextArg(); System.err.println(“\tpkg: ” + apkFilePath); if (apkFilePath == null) { System.err.println(“Error: no package specified”); showUsage(); return; } PackageInstallObserver obs = new PackageInstallObserver(); try { mPm.installPackage(Uri.fromFile(new File(apkFilePath)), obs, installFlags, installerPackageName); synchronized (obs) { while (!obs.finished) { try { obs.wait(); } catch (InterruptedException e) { } } if (obs.result == PackageManager.INSTALL_SUCCEEDED) { System.out.println(“Success”); } else { System.err.println(“Failure [” + installFailureToString(obs.result) + “]”); } } } catch (RemoteException e) { System.err.println(e.toString()); System.err.println(PM_NOT_RUNNING_ERR); } }
其中的PackageInstallObserver obs = new PackageInstallObserver();
mPm.installPackage(Uri.fromFile(new File(apkFilePath)), obs, installFlags, installerPackageName); 如果安装成功 obs.result == PackageManager.INSTALL_SUCCEEDED) 又因为有 IPackageManage mPm； mPm = IpackageManager.Stub.asInterface(ServiceManager.getService("package")); Stub是接口IPackageManage的静态抽象类，asInterface是返回IPackageManager代理的静态方法。 因为class PackageManagerService extends IPackageManager.Stub 所以mPm.installPackage 调用 /* Called when a downloaded package installation has been confirmed by the user */ public void installPackage( final Uri packageURI, final IPackageInstallObserver observer, final int flags,final String installerPackageName) 这样就是从网络下载安装的入口了。 #(4)从SD卡安装 系统调用PackageInstallerActivity.java（/home/zhongda/androidSRC/vortex-8inch-for-hoperun/packages/apps/PackageInstaller/src/com/android/packageinstaller） 进入这个Activity会判断信息是否有错，然后调用 private void initiateInstall()判断是否曾经有过同名包的安装，或者包已经安装 通过后执行private void startInstallConfirm() 点击OK按钮后经过一系列的安装信息的判断Intent跳转到[java] view plain copy public class InstallAppProgress extends Activity implements View.OnClickListener, OnCancelListener public void onCreate(Bundle icicle) { super.onCreate(icicle); Intent intent = getIntent(); mAppInfo = intent.getParcelableExtra(PackageUtil.INTENT_ATTR_APPLICATION_INFO); mPackageURI = intent.getData(); initView(); }
方法中调用了initView（）方法[java] view plain copy public void initView() { requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.op_progress); int installFlags = 0; PackageManager pm = getPackageManager(); try { PackageInfo pi = pm.getPackageInfo(mAppInfo.packageName, PackageManager.GET_UNINSTALLED_PACKAGES); if(pi != null) { installFlags |= PackageManager.INSTALL_REPLACE_EXISTING; } } catch (NameNotFoundException e) { } if((installFlags & PackageManager.INSTALL_REPLACE_EXISTING )!= 0) { Log.w(TAG, “Replacing package:” + mAppInfo.packageName); } PackageUtil.AppSnippet as = PackageUtil.getAppSnippet(this, mAppInfo, mPackageURI); mLabel = as.label; PackageUtil.initSnippetForNewApp(this, as, R.id.app_snippet); mStatusTextView = (TextView)findViewById(R.id.center_text); mStatusTextView.setText(R.string.installing); mProgressBar = (ProgressBar) findViewById(R.id.progress_bar); mProgressBar.setIndeterminate(true); // Hide button till progress is being displayed mOkPanel = (View)findViewById(R.id.buttons_panel); mDoneButton = (Button)findViewById(R.id.done_button); mLaunchButton = (Button)findViewById(R.id.launch_button); mOkPanel.setVisibility(View.INVISIBLE); String installerPackageName = getIntent().getStringExtra( Intent.EXTRA_INSTALLER_PACKAGE_NAME); PackageInstallObserver observer = new PackageInstallObserver(); pm.installPackage(mPackageURI, observer, installFlags, installerPackageName); }
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方法最后我们可以看到再次调用安装接口完成安装。
对于mSetting的介绍还不完善，后续会继续补充
本文是读过下面的几篇博客和Android系统源代码情景分析之后写成的，感谢各位作者。
参考：
http://ticktick.blog.51cto.com/823160/1669525 http://blog.csdn.net/hdhd588/article/details/6739281 http://blog.csdn.net/luoshengyang/article/details/6766010 《Android系统源代码情景分析》
