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。

PackageManagerService的作用总结：

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().

后面重点介绍installPackageLI，后面的额方式本质都会调用它。

（2）从网络上下载应用：

下载完成后，会自动调用Packagemanager的安装方法installPackage（）

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);     }  

通过PackageHandler的实例mhandler.sendMessage（msg）把信息发给继承Handler的类HandleMessage()方法

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

 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

@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

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。

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 copyprivate 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(）

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

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

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

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

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);     }  

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》

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