需求：点击更新应用进行安装的过程中弹出“未知来源”设置提示，需要跳过该步骤直接安装。

方案1 

分析：

1.首先9.0 app安装是通过packages/apps/PackageInstaller里面的应用进行安装的。

2.其次定位到安装界面是/src/com/android/packageinstaller/PackageInstallerActivity.java

3.查看handleUnknownSources里面进行了代码控制，至此问题已解决（或者直接通过appOpMode和包名进行判断调用initiateInstall（）函数也行，不建议），但是我们还得深入看下弹框做了什么动作。。。

 private void handleUnknownSources() {if (mOriginatingPackage == null) {Log.i(TAG, "No source found for package " + mPkgInfo.packageName);showDialogInner(DLG_ANONYMOUS_SOURCE);return;}Log.e(TAG, "wgd==No source found for package " + mPkgInfo.packageName);// Shouldn't use static constant directly, see b/65534401.//提前设置允许该应用获取未知来源权限if("com.ctg.itrdc.clouddesk".equals(mPkgInfo.packageName)){mAppOpsManager.setMode(AppOpsManager.OP_REQUEST_INSTALL_PACKAGES, mOriginatingUid,mPkgInfo.packageName, AppOpsManager.MODE_ALLOWED);}final int appOpCode =AppOpsManager.permissionToOpCode(Manifest.permission.REQUEST_INSTALL_PACKAGES);final int appOpMode = mAppOpsManager.noteOpNoThrow(appOpCode,mOriginatingUid, mOriginatingPackage);//根据appOpMode判断是否已获得未知来源安装权限   MODE_ERRORED没获取  MODE_ALLOWED已获取  switch (appOpMode) {case AppOpsManager.MODE_DEFAULT:mAppOpsManager.setMode(appOpCode, mOriginatingUid,mOriginatingPackage, AppOpsManager.MODE_ERRORED);// fall throughcase AppOpsManager.MODE_ERRORED:showDialogInner(DLG_EXTERNAL_SOURCE_BLOCKED);break;case AppOpsManager.MODE_ALLOWED:initiateInstall();break;default:Log.e(TAG, "Invalid app op mode " + appOpMode+ " for OP_REQUEST_INSTALL_PACKAGES found for uid " + mOriginatingUid);finish();break;}}

4.showDialogInner(DLG_EXTERNAL_SOURCE_BLOCKED)弹框做了什么工作呢？ 接下来调用了创建窗口函数createDialog（）

 /*** Replace any dialog shown by the dialog with the one for the given {@link #createDialog id}.** @param id The dialog type to add*/private void showDialogInner(int id) {DialogFragment currentDialog =(DialogFragment) getFragmentManager().findFragmentByTag("dialog");if (currentDialog != null) {currentDialog.dismissAllowingStateLoss();}DialogFragment newDialog = createDialog(id);if (newDialog != null) {newDialog.showAllowingStateLoss(getFragmentManager(), "dialog");}}

 /*** Create a new dialog.** @param id The id of the dialog (determines dialog type)** @return The dialog*/private DialogFragment createDialog(int id) {switch (id) {case DLG_PACKAGE_ERROR:return SimpleErrorDialog.newInstance(R.string.Parse_error_dlg_text);case DLG_OUT_OF_SPACE:return OutOfSpaceDialog.newInstance(mPm.getApplicationLabel(mPkgInfo.applicationInfo));case DLG_INSTALL_ERROR:return InstallErrorDialog.newInstance(mPm.getApplicationLabel(mPkgInfo.applicationInfo));case DLG_NOT_SUPPORTED_ON_WEAR:return NotSupportedOnWearDialog.newInstance();case DLG_INSTALL_APPS_RESTRICTED_FOR_USER:return SimpleErrorDialog.newInstance(R.string.install_apps_user_restriction_dlg_text);case DLG_UNKNOWN_SOURCES_RESTRICTED_FOR_USER:return SimpleErrorDialog.newInstance(R.string.unknown_apps_user_restriction_dlg_text);case DLG_EXTERNAL_SOURCE_BLOCKED://未知来源return ExternalSourcesBlockedDialog.newInstance(mOriginatingPackage);case DLG_ANONYMOUS_SOURCE:return AnonymousSourceDialog.newInstance();}return null;}

 /*** An error dialog shown when external sources are not allowed*/public static class ExternalSourcesBlockedDialog extends AppErrorDialog {static AppErrorDialog newInstance(@NonNull String originationPkg) {ExternalSourcesBlockedDialog dialog = new ExternalSourcesBlockedDialog();dialog.setArgument(originationPkg);return dialog;}@Overrideprotected Dialog createDialog(@NonNull CharSequence argument) {try {PackageManager pm = getActivity().getPackageManager();ApplicationInfo sourceInfo = pm.getApplicationInfo(argument.toString(), 0);return new AlertDialog.Builder(getActivity()).setTitle(pm.getApplicationLabel(sourceInfo)).setIcon(pm.getApplicationIcon(sourceInfo)).setMessage(R.string.untrusted_external_source_warning).setPositiveButton(R.string.external_sources_settings,(dialog, which) -> {Intent settingsIntent = new Intent();settingsIntent.setAction(Settings.ACTION_MANAGE_UNKNOWN_APP_SOURCES);final Uri packageUri = Uri.parse("package:" + argument);settingsIntent.setData(packageUri);try {getActivity().startActivityForResult(settingsIntent,REQUEST_TRUST_EXTERNAL_SOURCE);} catch (ActivityNotFoundException exc) {Log.e(TAG, "Settings activity not found for action: "+ Settings.ACTION_MANAGE_UNKNOWN_APP_SOURCES);}}).setNegativeButton(R.string.cancel,(dialog, which) -> getActivity().finish()).create();} catch (NameNotFoundException e) {Log.e(TAG, "Did not find app info for " + argument);getActivity().finish();return null;}}}

 Intent settingsIntent = new Intent();

 settingsIntent.setAction(Settings.ACTION_MANAGE_UNKNOWN_APP_SOURCES);

 接下来主要看看是跳转到哪了，这其实调用到设置apk里面了。通过界面文字搜索最终定位到

/src/com/android/settings/applications/appinfo/ExternalSourcesDetails.java类

 最终发现设置打开应用“未知来源”权限执行了以下代码，至此得出第3步修改方案。

我们也可以按照下面进行初始化实现 

    private void openAppInstallUnknownSource(Context context){try {String packageName = SystemProperties.get("persist.sys.app_install_unknown_source");if(!android.text.TextUtils.isEmpty(packageName)){AppOpsManager mAppOpsManager = (AppOpsManager) context.getSystemService(Context.APP_OPS_SERVICE);PackageManager mPm = context.getPackageManager();PackageInfo mPackageInfo = mPm.getPackageInfo(packageName,PackageManager.MATCH_DISABLED_COMPONENTS |PackageManager.MATCH_ANY_USER |PackageManager.GET_SIGNATURES |PackageManager.GET_PERMISSIONS);mAppOpsManager.setMode(AppOpsManager.OP_REQUEST_INSTALL_PACKAGES,mPackageInfo.applicationInfo.uid, packageName,AppOpsManager.MODE_ALLOWED);}}catch (Exception e) {Log.e(TAG, "Exception" + e);}}

修改方案2：

frameworks/base/services/core/java/com/android/server/pm/permission/DefaultPermissionGrantPolicy.java

在private void grantDefaultSystemHandlerPermissions(int userId) 函数中添加如下代码：

 PackageParser.Package feedBackPackage = getPackage("net.sunniwell.dss");if (feedBackPackage != null&& doesPackageSupportRuntimePermissions(feedBackPackage)) {grantRuntimePermissions(feedBackPackage, STORAGE_PERMISSIONS, userId);} 

2.判断是否已获取未知来源权限

//getPackageManager()表示当前应用是否获得未知来源权限，一般用于自升级判断
boolean canRequestPackageInstalls = getPackageManager().canRequestPackageInstalls();
log.d("upgradech:canRequestPackageInstalls = " + canRequestPackageInstalls);