和你一起终身学习，这里是程序员 Android
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.java
private 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
@Override
protected 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 pkg
try {
// 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
@Override
public 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
@Override
public 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：PackageHandler
public 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HandlerParams
final 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InstallParams
frameworks/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
@Override
void 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 installer
mLastScanError = 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//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 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();
}
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 installer
return 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：sgzy001/article/details/44857057
六、参考文献
【腾讯文档】Android Framework 知识库
https://docs.qq.com/doc/DSXBmSG9VbEROUXF5
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