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zbolg 去掉文章页带网站标题,推广网站排名优化seo教程,私家小庭院设计实景图,无锡网页设计培训公司和你一起终身学习，这里是程序员Android 经典好文推荐，通过阅读本文，您将收获以下知识点: 本篇文章主要介绍 Android 开发中的部分知识点，通过阅读本篇文章，您将收获以下内容: 一、前言二、PackageInstaller介绍三、App…

和你一起终身学习，这里是程序员Android

经典好文推荐，通过阅读本文，您将收获以下知识点:

本篇文章主要介绍 Android 开发中的部分知识点，通过阅读本篇文章，您将收获以下内容:

一、前言
二、PackageInstaller介绍
三、App安装过程中涉及类
四、App安装流程分析
五、总结
六、参考文献

一、前言

首先本文不是做PackageManagerService学习总结，PackageManagerService这货有1万2千多行代码，学习起来颇费劲，并且这货功能强大，本文只会总结其中一个小小的功能
为何要做这个总结呢？说来话长，鄙人菜鸟一枚，接到一个安装应用过程中重启的问题，原因找到，但不知如何解决，无奈，只有硬着头皮学习了下这部分内容
OK，废话不多说，接下来直接上干货，如果文中有问题或有质疑的地方可以直接修改，不胜感激。

二、PackageInstaller介绍

PackageInstaller是个神马东西呢？
我们知道安装app有很多中方式，诸如adb install,应用助手（豌豆荚）,开机安装（开机启动时），下载到手机存储后点击安装。PackageInstaller这哥就是给手动安装app提供一个界面的apk。
当我们点安装应用时会启动这个应用来显示安装过程，安装的事情并不是他在做，正在安装是由PackageManagerService来完成，当然幕后英雄确是Installer。
代码位置
packages/apps/PackageInstaller
疑问【以下有几个问题，如果亲都知道的话，那么可以不用再看本文啦】
如何使用PackageInstaller来安装应用？
应用首选安装位置是在何时确定的？是在设置里设置的，还是在app中定义的，还是PackageManagerService这货说了算？
安装应用过程中，哪些服务和类会插手这件事？
安装过程中首先会生成一个.tmp临时文件，这个文件在何时被rename为apk的？
应用都有uid，这个uid是在什么时候被赋值的？
packages.xml and packages.list有什么用？
安装app主要做了哪些事？

三、App安装过程中涉及类

先来盘类图看看，如对PackageManagerService不熟悉的话，先看后面的流程，看完再来看这个类图

安装过程时会插手的主要类如下

packages/apps/PackageInstaller/src/com/android/packageinstaller/PackageInstallerActivity.java
packages/apps/PackageInstaller/src/com/android/packageinstaller/InstallAppProgress.java
frameworks/base /core/java/android/app/ApplicationPackageManager.java
frameworks/base /core/java/android/content/pm/PackageParser.java
frameworks/base /core/java/android/content/res/AssetManager.java
frameworks/base /packages/DefaultContainerService/src/com/android/defcontainer/DefaultContainerService.java
frameworks/base /services/java/com/android/server/pm/Installer.java
frameworks/base /services/java/com/android/server/pm/PackageManagerService.java
frameworks/base /services/java/com/android/server/pm/Settings.java

简单说明这些类作用

PackageInstallerActivity.java：
在文件管理器里点击apk后就会调用该类，主要用于显示要安装的apk的一些权限信息
InstallAppProgress.java：
当看完所有权限后，点安装后就会调用该类，用于显示安装进度，这时候- PackageManagerService 就在默默的安装应用
ApplicationPackageManager.java：
这是类是PackageManager的儿子，我们使用mContext.getPackageManager得到的其实就是ApplicationPackageManager的对象，它爹PackageManager是个抽象类，对外的方法都定义在里面
PackageParser.java：
解析app，主要解析apk中的AndroidManifest.xml，解析里面的四大组件以及权限信息放入内存里，最后写到packages.xml和package.list（/data/system下）中
AssetManager.java：
把AndroidManifest.xml从app中拿出来给PackageParser.java去解析
DefaultContainerService.java：
这个服务用于检查存储状态，得到合适的安装位置
Installer.java：
PackageManagerService调用它去执行安装，他会把PackageManagerService传过来的数据封装成命令，然后让底层的Installer去执行
PackageManagerService.java：
管理app的大神，安装、移动、卸载、查询等都由他管

四、App安装流程分析

先来个时序图--安装成功的时序图。点击两次可看大图

安装流程

流程分析，当然对着代码看上面的时序图也很明了
1.当点击文件管理器中的apk时，会调用FolderFragment的openFile方法，该方法里会将应用信息传给PackageInstallerActivity，并启动PackageInstaller

代码位置：vendor/qcom/proprietary/qrdplus/FileExplorer/src/com/android/qrdfileexplorer/FolderFragment.javaprivate void openFile(File f) {final Uri fileUri = Uri.fromFile(f);final Intent intent = new Intent();intent.setAction(android.content.Intent.ACTION_VIEW);intent.putExtra(Intent.EXTRA_TITLE, f.getName());intent.putExtra(EXTRA_ALL_VIDEO_FOLDER, true);Uri contentUri = null;String type = getMIMEType(f);......if (contentUri != null) {intent.setDataAndType(contentUri, type);} else {intent.setDataAndType(fileUri, type);}try {startActivitySafely(intent);} ......}

2.PackageInstaller启动过后会检查是否开启未知来源，未开启就需要先进入设置设置后，方可继续安装，之后会依次调用initiateInstall()->startInstallConfirm();
在initiateInstall中会检查是否已经安装过，是否是系统应用等，调用startInstallConfirm去初始化界面，显示权限信息，当点击安装按钮时，启动安装，切换界面到InstallAppProgress

代码位置：packages/apps/PackageInstaller/src/com/android/packageinstaller/PackageInstallerActivity.java@Overrideprotected void onCreate(Bundle icicle) {......mPm = getPackageManager();boolean requestFromUnknownSource = isInstallRequestFromUnknownSource(intent);......initiateInstall();}private void initiateInstall() {String pkgName = mPkgInfo.packageName;String[] oldName = mPm.canonicalToCurrentPackageNames(new String[] { pkgName });if (oldName != null && oldName.length > 0 && oldName[0] != null) {pkgName = oldName[0];mPkgInfo.packageName = pkgName;mPkgInfo.applicationInfo.packageName = pkgName;}// Check if package is already installed. display confirmation dialog if replacing pkgtry {// This is a little convoluted because we want to get all uninstalled// apps, but this may include apps with just data, and if it is just// data we still want to count it as "installed".mAppInfo = mPm.getApplicationInfo(pkgName,PackageManager.GET_UNINSTALLED_PACKAGES);if ((mAppInfo.flags&ApplicationInfo.FLAG_INSTALLED) == 0) {mAppInfo = null;}} catch (NameNotFoundException e) {mAppInfo = null;}mInstallFlowAnalytics.setReplace(mAppInfo != null);mInstallFlowAnalytics.setSystemApp((mAppInfo != null) && ((mAppInfo.flags & ApplicationInfo.FLAG_SYSTEM) != 0));startInstallConfirm();}

3.在InstallAppProgress中会调用initView去初始化界面并调用ApplicationPackageManager的installPackageWithVerificationAndEncryption方法来安装

代码位置：packages/apps/PackageInstaller/src/com/android/packageinstaller/InstallAppProgress.java@Overridepublic void onCreate(Bundle icicle) {......initView();}public void initView() {......if ("package".equals(mPackageURI.getScheme())) {try {pm.installExistingPackage(mAppInfo.packageName);observer.packageInstalled(mAppInfo.packageName,PackageManager.INSTALL_SUCCEEDED);} catch (PackageManager.NameNotFoundException e) {observer.packageInstalled(mAppInfo.packageName,PackageManager.INSTALL_FAILED_INVALID_APK);}} else {pm.installPackageWithVerificationAndEncryption(mPackageURI, observer, installFlags,installerPackageName, verificationParams, null);}}

4.ApplicationPackageManager的installPackageWithVerificationAndEncryption里也是调用PMS的installPackageWithVerificationAndEncryption方法

代码位置：frameworks/base/core/java/android/app/ApplicationPackageManager.java@Overridepublic void installPackageWithVerificationAndEncryption(Uri packageURI,IPackageInstallObserver observer, int flags, String installerPackageName,VerificationParams verificationParams, ContainerEncryptionParams encryptionParams) {try {mPM.installPackageWithVerificationAndEncryption(packageURI, observer, flags,installerPackageName, verificationParams, encryptionParams);} catch (RemoteException e) {// Should never happen!}}

5.installPackageWithVerificationAndEncryption方法里，首先会获取设置中的用户安装位置，并且会把InstallParams对象和安装位置flag封装到Message里，然后发出一个消息后就撒手不管了。

代码位置：frameworks/base/services/java/com/android/server/pm/PackageManagerService.java
public void installPackageWithVerificationAndEncryption(Uri packageURI,IPackageInstallObserver observer, int flags, String installerPackageName,VerificationParams verificationParams, ContainerEncryptionParams encryptionParams) {mContext.enforceCallingOrSelfPermission(android.Manifest.permission.INSTALL_PACKAGES,null);final int uid = Binder.getCallingUid();if(getInstallLocation() == PackageHelper.APP_INSTALL_INTERNAL){userFilteredFlags = flags |PackageManager.INSTALL_INTERNAL;} else if(getInstallLocation() == PackageHelper.APP_INSTALL_EXTERNAL){userFilteredFlags = flags |PackageManager.INSTALL_EXTERNAL;} else{userFilteredFlags = filteredFlags;}final Message msg = mHandler.obtainMessage(INIT_COPY);msg.obj = new InstallParams(packageURI, observer, userFilteredFlags, installerPackageName,verificationParams, encryptionParams, user);mHandler.sendMessage(msg);}

6.接下来就该PackageHandler上场了，会依次处理INIT_COPY、MCS_BOUN消息，这里面会去连接DefaultContainerService服务，接着会InstallParams的startCopy方法

代码位置：frameworks/base/services/java/com/android/server/pm/PackageManagerService.java ->内部类：PackageHandlerpublic void handleMessage(Message msg) {try {doHandleMessage(msg);} finally {Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);}}void doHandleMessage(Message msg) {switch (msg.what) {case INIT_COPY: {HandlerParams params = (HandlerParams) msg.obj;if (!mBound) {if (!connectToService()) {params.serviceError();return;} else {mPendingInstalls.add(idx, params);}} else {mPendingInstalls.add(idx, params);if (idx == 0) {mHandler.sendEmptyMessage(MCS_BOUND);}}break;}case MCS_BOUN: {if (msg.obj != null) {mContainerService = (IMediaContainerService) msg.obj;}if (mContainerService == null) {for (HandlerParams params : mPendingInstalls) {params.serviceError();}mPendingInstalls.clear();} else if (mPendingInstalls.size() > 0) {HandlerParams params = mPendingInstalls.get(0);if (params != null) {if (params.startCopy()) {......}}} else {Slog.w(TAG, "Empty queue");}break;}......case POST_INSTALL: {...if (data != null) {InstallArgs args = data.args;PackageInstalledInfo res = data.res;if (res.returnCode == PackageManager.INSTALL_SUCCEEDED) {......sendPackageBroadcast(Intent.ACTION_PACKAGE_ADDED,res.pkg.applicationInfo.packageName, extras, null, null, firstUsers);final boolean update = res.removedInfo.removedPackage != null;if (update) {extras.putBoolean(Intent.EXTRA_REPLACING, true);}sendPackageBroadcast(Intent.ACTION_PACKAGE_ADDED,res.pkg.applicationInfo.packageName, extras, null, null, updateUsers);if (update) {sendPackageBroadcast(Intent.ACTION_PACKAGE_REPLACED,res.pkg.applicationInfo.packageName, extras, null, null, updateUsers);sendPackageBroadcast(Intent.ACTION_MY_PACKAGE_REPLACED,null, null, res.pkg.applicationInfo.packageName, null, updateUsers);if (isForwardLocked(res.pkg) || isExternal(res.pkg)) {......sendResourcesChangedBroadcast(true, true, pkgList,uidArray, null);}}if (res.removedInfo.args != null) {deleteOld = true;}}......if (args.observer != null) {try {args.observer.packageInstalled(res.name, res.returnCode);} catch (RemoteException e) {Slog.i(TAG, "Observer no longer exists.");}}} else {Slog.e(TAG, "Bogus post-install token " + msg.arg1);}break;}}}

7.InstallParams的startCopy方法里，会调用handleStartCopy方法

代码位置：frameworks/base/services/java/com/android/server/pm/PackageManagerService.java ->内部类：InstallParams 继承于HandlerParamsfinal boolean startCopy() {boolean res;try {if (++mRetries > MAX_RETRIES) {Slog.w(TAG, "Failed to invoke remote methods on default container service. Giving up");mHandler.sendEmptyMessage(MCS_GIVE_UP);handleServiceError();return false;} else {handleStartCopy();res = true;}} catch (RemoteException e) {mHandler.sendEmptyMessage(MCS_RECONNECT);res = false;}handleReturnCode();return res;}

8.handleStartCopy方法中会检查应用是否能安装，如不合法则返回FAILED的CODE，接着会调用DefaultContainerService的getMinimalPackageInfo方法，该方法用于获取存储状态，返回合适的安装位置
如果返回码是INSTALL_SUCCEEDED，那接下来就会调用InstallParams的copyApk，如果安装到内置，调用的就是FileInstallArgs的copyApk方法，如安装到外置就调用AsecInstallArgs的copyApk方法
AsecInstallArgs和FileInstallArgs都是InstallParams的子类

代码位置：frameworks/base/services/java/com/android/server/pm/PackageManagerService.java ->内部类：FileInstallArgs 继承于InstallParams
public void handleStartCopy() throws RemoteException {......if (onInt && onSd) {ret = PackageManager.INSTALL_FAILED_INVALID_INSTALL_LOCATION;} else {......try {mContext.grantUriPermission(DEFAULT_CONTAINER_PACKAGE, mPackageURI,Intent.FLAG_GRANT_READ_URI_PERMISSION);........if (packageFile != null) {......pkgLite = mContainerService.getMinimalPackageInfo(packageFilePath, flags, lowThreshold);}}}final InstallArgs args = createInstallArgs(this);mArgs = args;......if (ret == PackageManager.INSTALL_SUCCEEDED) {......ret = args.copyApk(mContainerService, true);......}mRet = ret;}

9.copyApk方法中会依次调用FileInstallArgs 的createCopyFile->PackageManagerService的createTempPackageFile方法去创建临时文件。

代码位置：frameworks/base/services/java/com/android/server/pm/PackageManagerService.java ->内部类：FileInstallArgs 继承于InstallParamsframeworks/base/services/java/com/android/server/pm/PackageManagerService.java
vmdl*.tmp就是copy成的临时文件void createCopyFile() {installDir = isFwdLocked() ? mDrmAppPrivateInstallDir : mAppInstallDir;codeFileName = createTempPackageFile(installDir).getPath();resourceFileName = getResourcePathFromCodePath();libraryPath = getLibraryPathFromCodePath();created = true;}private File createTempPackageFile(File installDir) {File tmpPackageFile;try {tmpPackageFile = File.createTempFile("vmdl", ".tmp", installDir);} catch (IOException e) {Slog.e(TAG, "Couldn't create temp file for downloaded package file.");return null;}try {FileUtils.setPermissions(tmpPackageFile.getCanonicalPath(), FileUtils.S_IRUSR|FileUtils.S_IWUSR,-1, -1);if (!SELinux.restorecon(tmpPackageFile)) {return null;}} catch (IOException e) {Slog.e(TAG, "Trouble getting the canoncical path for a temp file.");return null;}return tmpPackageFile;}

10.临时文件已经有了，handleStartCopy方法走完，接着回到步骤7，调用InstallParams的handleReturnCode方法，handleReturnCode中会执行processPendingInstall，在该方法中做了大量工作

@Overridevoid handleReturnCode() {if (mArgs != null) {processPendingInstall(mArgs, mRet);if (mTempPackage != null) {if (!mTempPackage.delete()) {Slog.w(TAG, "Couldn't delete temporary file: " +mTempPackage.getAbsolutePath());}}}}

11.来看看processPendingInstall到底做了什么？processPendingInstall中最关键方法--installPackageLI，主要的操作（验证签名，创建/data/data，分配UID,dexopt）都在这个方法中完成。

private void processPendingInstall(final InstallArgs args, final int currentStatus) {mHandler.post(new Runnable() {public void run() {mHandler.removeCallbacks(this);PackageInstalledInfo res = new PackageInstalledInfo();res.returnCode = currentStatus;res.uid = -1;res.pkg = null;res.removedInfo = new PackageRemovedInfo();if (res.returnCode == PackageManager.INSTALL_SUCCEEDED) {args.doPreInstall(res.returnCode);synchronized (mInstallLock) {installPackageLI(args, true, res);}args.doPostInstall(res.returnCode, res.uid);}......if (!doRestore) {Message msg = mHandler.obtainMessage(POST_INSTALL, token, 0);mHandler.sendMessage(msg);}}});}

12.我们来看一下installPackageLI方法，首选会让parsePackage去解析apk里的AndroidManifest.xml,使用的是parsePackage方法，把解析出来的内容放到Package对象中
接着调用doRename去将之前的tmp文件重命名为apk。apk已经在/data/app下了，apk的属性也被解析出来放在内存（Package对象）中了
那么现在还需要做什么呢？apk有了，数据目录(/data/data）还没有，所以后面会进行uid赋值，验证签名，创建相应的/data/data目录，dexopt操作，这些工作是由installNewPackageLI来完成

private void installPackageLI(InstallArgs args,boolean newInstall, PackageInstalledInfo res) {......int parseFlags = mDefParseFlags | PackageParser.PARSE_CHATTY| (forwardLocked ? PackageParser.PARSE_FORWARD_LOCK : 0)| (onSd ? PackageParser.PARSE_ON_SDCARD : 0);PackageParser pp = new PackageParser(tmpPackageFile.getPath());pp.setSeparateProcesses(mSeparateProcesses);final PackageParser.Package pkg = pp.parsePackage(tmpPackageFile,null, mMetrics, parseFlags);......if (!args.doRename(res.returnCode, pkgName, oldCodePath)) {res.returnCode = PackageManager.INSTALL_FAILED_INSUFFICIENT_STORAGE;return;}......if (replace) {replacePackageLI(pkg, parseFlags, scanMode, args.user,installerPackageName, res);} else {installNewPackageLI(pkg, parseFlags, scanMode | SCAN_DELETE_DATA_ON_FAILURES, args.user,installerPackageName, res);}synchronized (mPackages) {final PackageSetting ps = mSettings.mPackages.get(pkgName);if (ps != null) {res.newUsers = ps.queryInstalledUsers(sUserManager.getUserIds(), true);}}}

13.让我们来看看installNewPackageLI具体怎么完成这些工作的吧。

private void installNewPackageLI(PackageParser.Package pkg,int parseFlags, int scanMode, UserHandle user,String installerPackageName, PackageInstalledInfo res) {......PackageParser.Package newPackage = scanPackageLI(pkg, parseFlags, scanMode, System.currentTimeMillis(), user);if (newPackage == null) {......} else {updateSettingsLI(newPackage, installerPackageName, null, null, res);......if (res.returnCode != PackageManager.INSTALL_SUCCEEDED) {deletePackageLI(pkgName, UserHandle.ALL, false, null, null, dataDirExists ? PackageManager.DELETE_KEEP_DATA : 0,res.removedInfo, true);}}}

14.scanPackageLI方法中，先调用getPackageLPw->newUserIdLPw（Settings类方法)去设置uid，在调用verifySignaturesLP验证签名
然后调用createDataDirsLI创建/data/data数据目录，最后调用performDexOptLI进行dexopt操作
createDataDirsLI是靠调用mInstaller.install方法来完成目录创建，framework中的Installer会和底层幕后Installer勾兑，完成目录创建工作
performDexOptLI操作最后也是通过mInstaller.dexopt来完成的

private PackageParser.Package scanPackageLI(PackageParser.Package pkg,int parseFlags, int scanMode, long currentTime, UserHandle user) {......synchronized (mPackages) {......pkgSetting = mSettings.getPackageLPw(pkg, origPackage, realName, suid, destCodeFile,destResourceFile, pkg.applicationInfo.nativeLibraryDir,pkg.applicationInfo.flags, user, false);if (pkgSetting == null) {mLastScanError = PackageManager.INSTALL_FAILED_INSUFFICIENT_STORAGE;return null;}......if (!verifySignaturesLP(pkgSetting, pkg)) {if ((parseFlags&PackageParser.PARSE_IS_SYSTEM_DIR) == 0) {return null;}// The signature has changed, but this package is in the system// image...  let's recover!pkgSetting.signatures.mSignatures = pkg.mSignatures;// However...  if this package is part of a shared user, but it// doesn't match the signature of the shared user, let's fail.// What this means is that you can't change the signatures// associated with an overall shared user, which doesn't seem all// that unreasonable.if (pkgSetting.sharedUser != null) {if (compareSignatures(pkgSetting.sharedUser.signatures.mSignatures,pkg.mSignatures) != PackageManager.SIGNATURE_MATCH) {Log.w(TAG, "Signature mismatch for shared user : " + pkgSetting.sharedUser);mLastScanError = PackageManager.INSTALL_PARSE_FAILED_INCONSISTENT_CERTIFICATES;return null;}}// File a report about this.String msg = "System package " + pkg.packageName+ " signature changed; retaining data.";reportSettingsProblem(Log.WARN, msg);}......}......if (mPlatformPackage == pkg) {......} else {......if (dataPath.exists()) {......} else {......int ret = createDataDirsLI(pkgName, pkg.applicationInfo.uid,pkg.applicationInfo.seinfo);if (ret < 0) {// Error from installermLastScanError = PackageManager.INSTALL_FAILED_INSUFFICIENT_STORAGE;return null;}if (dataPath.exists()) {pkg.applicationInfo.dataDir = dataPath.getPath();} else {Slog.w(TAG, "Unable to create data directory: " + dataPath);pkg.applicationInfo.dataDir = null;}}/** Set the data dir to the default "/data/data/<package name>/lib"* if we got here without anyone telling us different (e.g., apps* stored on SD card have their native libraries stored in the ASEC* container with the APK).** This happens during an upgrade from a package settings file that* doesn't have a native library path attribute at all.*/if (pkg.applicationInfo.nativeLibraryDir == null && pkg.applicationInfo.dataDir != null) {if (pkgSetting.nativeLibraryPathString == null) {setInternalAppNativeLibraryPath(pkg, pkgSetting);} else {pkg.applicationInfo.nativeLibraryDir = pkgSetting.nativeLibraryPathString;}}pkgSetting.uidError = uidError;}......// We also need to dexopt any apps that are dependent on this library.  Note that// if these fail, we should abort the install since installing the library will// result in some apps being broken.if (clientLibPkgs != null) {if ((scanMode&SCAN_NO_DEX) == 0) {for (int i=0; i<clientLibPkgs.size(); i++) {PackageParser.Package clientPkg = clientLibPkgs.get(i);if (performDexOptLI(clientPkg, forceDex, (scanMode&SCAN_DEFER_DEX) != 0, false)== DEX_OPT_FAILED) {if ((scanMode & SCAN_DELETE_DATA_ON_FAILURES) != 0) {removeDataDirsLI(pkg.packageName);}mLastScanError = PackageManager.INSTALL_FAILED_DEXOPT;return null;}}}}// Request the ActivityManager to kill the process(only for existing packages)// so that we do not end up in a confused state while the user is still using the older// version of the application while the new one gets installed.......// Also need to kill any apps that are dependent on the library.......return pkg;}private int createDataDirsLI(String packageName, int uid, String seinfo) {int[] users = sUserManager.getUserIds();int res = mInstaller.install(packageName, uid, uid, seinfo);if (res < 0) {return res;}for (int user : users) {if (user != 0) {res = mInstaller.createUserData(packageName,UserHandle.getUid(user, uid), user);if (res < 0) {return res;}}}return res;}private int performDexOptLI(PackageParser.Package pkg, boolean forceDex, boolean defer,boolean inclDependencies) {......return performDexOptLI(pkg, forceDex, defer, done);}private int performDexOptLI(PackageParser.Package pkg, boolean forceDex, boolean defer,HashSet<String> done) {......if ((pkg.applicationInfo.flags&ApplicationInfo.FLAG_HAS_CODE) != 0) {......try {if (forceDex || dalvik.system.DexFile.isDexOptNeeded(path)) {if (!forceDex && defer) {if (mDeferredDexOpt == null) {mDeferredDexOpt = new HashSet<PackageParser.Package>();}mDeferredDexOpt.add(pkg);return DEX_OPT_DEFERRED;} else {final int sharedGid = UserHandle.getSharedAppGid(pkg.applicationInfo.uid);ret = mInstaller.dexopt(path, sharedGid, !isForwardLocked(pkg));pkg.mDidDexOpt = true;performed = true;}}} catch (FileNotFoundException e) {......} catch (IOException e) {......} catch (dalvik.system.StaleDexCacheError e) {......} catch (Exception e) {......}if (ret < 0) {//error from installerreturn DEX_OPT_FAILED;}}return performed ? DEX_OPT_PERFORMED : DEX_OPT_SKIPPED;}
performDexOptLI后生成的文件

15.到目前为止，scanPackageLI已经走完了，接下来就该更新packages.list,packages.xml了
系统中所有app的信息都保存在这两个文件中，当有app安装、卸载、更新时都会更新这两个文件
回到步骤13，当installNewPackageLI中的scanPackageLI走完后，后面会调用updateSettingsLI去更新文件
mSettings.writeLPr()来完成往packages.list,packages.xml中更新数据

private void updateSettingsLI(PackageParser.Package newPackage, String installerPackageName,int[] allUsers, boolean[] perUserInstalled,PackageInstalledInfo res) {String pkgName = newPackage.packageName;synchronized (mPackages) {......mSettings.setInstallStatus(pkgName, PackageSettingBase.PKG_INSTALL_INCOMPLETE);mSettings.writeLPr();}......synchronized (mPackages) {updatePermissionsLPw(newPackage.packageName, newPackage,UPDATE_PERMISSIONS_REPLACE_PKG | (newPackage.permissions.size() > 0? UPDATE_PERMISSIONS_ALL : 0));......mSettings.writeLPr();}}

packages.list文件部分截取

packages.xml部分截取，包含包名，安装时间，签名，权限，文件安装路径等信息

16.installPackageLI到这里已经执行完了，现在回到步骤11，后续会执行到Message msg = mHandler.obtainMessage(POST_INSTALL, token, 0); mHandler.sendMessage(msg);发送消息
消息发出后，回到步骤POST_INSTALL，这里面主要做了两件事，发生一条ACTION_PACKAGE_ADDED广播告诉大家，又有新包了，这是launcher什么的赶紧把图标加上
然后回调args.observer.packageInstalled(res.name, res.returnCode);告诉PackageInstaller安装结果
然后就显示安装完成界面。欧拉，应用安装结束。

五、总结

小结一下安装app到底主要做了哪些事情？

1.验证是否允许安装未知来源应用
2.得到用户设置的首选安装位置
3.检验app有效性，检查存储状态，得到最佳安装位置
4.拷贝app到安装位置，此时为.tmp临时文件
5.解析AndroidManifest.xml
6.重命名tmp为apk
7.赋值UID，验证权限
8.创建/data/data/下数据目录
9.执行dexopt操作
10.更新packages.xml,packages.list
11.发送广播，回调安装状态

原文作者：默默9518
原文链接：https://sgzy001/article/details/44857057

参考文献：

【腾讯文档】Android Framework 知识库
https://docs.qq.com/doc/DSXBmSG9VbEROUXF5

友情推荐：

Android 开发干货集锦

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