Android AB升级（二） - Demo APP应用流程
Android源码有车机系统升级的demo app：SystemUpdater，使用原生settings UI画面。该应用可用于理解应用层同系统层进行交互，触发完成升级的逻辑流程。
1. demo app目录结构
1.1. 文件目录
该demo app是专用于汽车升级的示例apk，源码路径：packages/apps/Car/SystemUpdater
android/packages/apps/Car/SystemUpdater$ tree
.
├── AndroidManifest.xml
├── Android.mk
├── PREUPLOAD.cfg
├── res
│ ├── .....
└── src└── com└── android└── car└── systemupdater├── DeviceListFragment.java├── SystemUpdaterActivity.java├── UpdateLayoutFragment.java├── UpdateParser.java└── UpFragment.java1.2. Android.mk
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)LOCAL_MODULE_TAGS := optional
# 模块src路径加载
LOCAL_SRC_FILES := $(call all-java-files-under, src)
# 资源加载
LOCAL_RESOURCE_DIR := $(LOCAL_PATH)/res
# 定义该应用是platform app
LOCAL_CERTIFICATE := platform
# APP名称
LOCAL_PACKAGE_NAME := SystemUpdater
LOCAL_PRIVATE_PLATFORM_APIS := true
# 是否预编译
LOCAL_DEX_PREOPT := false
# 此常量为是否使用aapt2
LOCAL_USE_AAPT2 := true
# 控制是否开启proguard，默认值为full
LOCAL_PROGUARD_ENABLED := disabledLOCAL_DX_FLAGS := --multi-dex# This module depends on androidx.car_car for legacy reasons.
# Don't copy-paste the use of androidx.car_car
# 依赖库
LOCAL_STATIC_ANDROID_LIBRARIES := \androidx.car_car \androidx.legacy_legacy-support-v4 \androidx.appcompat_appcompatinclude $(BUILD_PACKAGE)
1.3. AndroidManifest.xml
<!-- 包名 -->
<manifestxmlns:android="http://schemas.android.com/apk/res/android"package="com.android.car.systemupdater">
<!-- 应用外部存储读写权限、重启权限、usb权限 --><uses-permission android:name="android.permission.WRITE_MEDIA_STORAGE" /><uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /><uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /><uses-permission android:name="android.permission.REBOOT" /><uses-feature android:name="android.hardware.usb.host" />
<!-- 使用settings主题歌和标题目录 --><applicationandroid:label="@string/title"android:theme="@style/SystemUpdaterTheme"><activityandroid:name="com.android.car.systemupdater.SystemUpdaterActivity"android:label="@string/title"><intent-filter><action android:name="android.intent.action.MAIN" /></intent-filter><intent-filter><action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" /></intent-filter><intent-filter><action android:name="com.android.settings.action.EXTRA_SETTINGS" /><category android:name="android.intent.category.DEFAULT" /></intent-filter><meta-data android:name="com.android.settings.title"android:resource="@string/title" /><meta-data android:name="com.android.settings.icon"android:resource="@drawable/ic_system_update_alt_black_48dp" /><meta-data android:name="com.android.settings.category"android:value="com.android.settings.category.ia.system" /></activity></application>
</manifest>
2. applyPayload触发流程
2.1. SystemUpdaterActivity启动
//packages/apps/Car/SystemUpdater/src/com/android/car/systemupdater/SystemUpdaterActivity.java
public class SystemUpdaterActivity extends AppCompatActivityimplements DeviceListFragment.SystemUpdater {private static final String FRAGMENT_TAG = "FRAGMENT_TAG";private static final int STORAGE_PERMISSIONS_REQUEST_CODE = 0;//权限private static final String[] REQUIRED_STORAGE_PERMISSIONS = new String[]{Manifest.permission.READ_EXTERNAL_STORAGE,Manifest.permission.WRITE_EXTERNAL_STORAGE,Manifest.permission.WRITE_MEDIA_STORAGE};@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);//check 权限if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE)!= PackageManager.PERMISSION_GRANTED) {ActivityCompat.requestPermissions(this, REQUIRED_STORAGE_PERMISSIONS,STORAGE_PERMISSIONS_REQUEST_CODE);}setContentView(R.layout.activity_main);Toolbar toolbar = findViewById(R.id.toolbar);setSupportActionBar(toolbar);if (savedInstanceState == null) {Bundle intentExtras = getIntent().getExtras();if (intentExtras != null && intentExtras.getBoolean(EXTRA_RESUME_UPDATE)) {//创建UpdateLayoutFragment对象，调用newResumedInstanceUpdateLayoutFragment fragment = UpdateLayoutFragment.newResumedInstance();getSupportFragmentManager().beginTransaction().replace(R.id.device_container, fragment, FRAGMENT_TAG).commitNow();} else {//创建DeviceListFragment对象DeviceListFragment fragment = new DeviceListFragment();getSupportFragmentManager().beginTransaction().replace(R.id.device_container, fragment, FRAGMENT_TAG).commitNow();}}}.....
2.2. DeviceListFragment开始升级准备
（1） DeviceListFragment.java - onCreate
@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);Context context = getContext();mItemProvider = new FileItemProvider(context);mStorageManager = (StorageManager) context.getSystemService(Context.STORAGE_SERVICE);if (mStorageManager == null) {if (Log.isLoggable(TAG, Log.WARN)) {Log.w(TAG, "Failed to get StorageManager");}Toast.makeText(context, R.string.cannot_access_storage, Toast.LENGTH_LONG).show();return;}}
（2）调用get(int position)函数
（3）调用onFileSelected(File file)选中的升级包文件
（4）如果升级包存在，则调用mSystemUpdater.applyUpdate(file)，该接口由SystemUpdaterActivity实现
//DeviceListFragment.java/** Used to request installation of an update. */interface SystemUpdater {/** Attempt to apply an update to the device contained in the {@code file}. */void applyUpdate(File file);}
（5）SystemUpdaterActivity.java - applyUpdate，获取UpdateLayoutFragment对象，传入升级路径
@Overridepublic void applyUpdate(File file) {//new UpdateLayoutFragment()对象//new Bundle对象UpdateLayoutFragment fragment = UpdateLayoutFragment.getInstance(file);getSupportFragmentManager().beginTransaction().replace(R.id.device_container, fragment, FRAGMENT_TAG).addToBackStack(null).commit();}
（6）调用UpdateLayoutFragment.java - onActivityCreated，然后调用mPackageVerifier.execute(mUpdateFile)
@Overridepublic void onActivityCreated(Bundle savedInstanceState) {super.onActivityCreated(savedInstanceState);.....if (getArguments().getBoolean(EXTRA_RESUME_UPDATE)) {//显示install进度showInstallationInProgress();} else {//执行必要的步骤开始升级mPackageVerifier.execute(mUpdateFile);}}
//UpdateLayoutFragment.java
//该类继承AsyncTask
//尝试验证更新并提取安装所需的信息private class UpdateVerifier extends AsyncTask<File, Void, UpdateParser.ParsedUpdate> {@Overrideprotected UpdateParser.ParsedUpdate doInBackground(File... files) {Preconditions.checkArgument(files.length > 0, "No file specified");File file = files[0];try {//调用UpdateParser.java的parse解析升级包文件return UpdateParser.parse(file);} catch (IOException e) {Log.e(TAG, String.format("For file %s", file), e);return null;}}@Overrideprotected void onPostExecute(UpdateParser.ParsedUpdate result) {mProgressBar.setVisibility(View.GONE);if (result == null) {showStatus(R.string.verify_failure);return;}if (!result.isValid()) {showStatus(R.string.verify_failure);Log.e(TAG, String.format("Failed verification %s", result));return;}if (Log.isLoggable(TAG, Log.INFO)) {Log.i(TAG, result.toString());}//调用installUpdate，然后调用mUpdateEngine.applyPayload传入升级所需要的url，偏移量，大小等开始升级showInstallNow(result);}}
2.2.1. UpdateParser.parse解析升级文件
//packages/apps/Car/SystemUpdater/src/com/android/car/systemupdater/UpdateParser.javastatic ParsedUpdate parse(@NonNull File file) throws IOException {Preconditions.checkNotNull(file);long payloadOffset = 0;long payloadSize = 0;boolean payloadFound = false;String[] props = null;try (ZipFile zipFile = new ZipFile(file)) {Enumeration<? extends ZipEntry> entries = zipFile.entries();while (entries.hasMoreElements()) {ZipEntry entry = entries.nextElement();long fileSize = entry.getCompressedSize();if (!payloadFound) {payloadOffset += ZIP_FILE_HEADER + entry.getName().length();if (entry.getExtra() != null) {payloadOffset += entry.getExtra().length;}}if (entry.isDirectory()) {continue;} else if (entry.getName().equals(PAYLOAD_BIN_FILE)) {payloadSize = fileSize; //payload.bin升级数据文件的大小payloadFound = true;} else if (entry.getName().equals(PAYLOAD_PROPERTIES)) {try (BufferedReader buffer = new BufferedReader(new InputStreamReader(zipFile.getInputStream(entry)))) {props = buffer.lines().toArray(String[]::new); //hash值}}if (!payloadFound) {payloadOffset += fileSize; //偏移量}if (Log.isLoggable(TAG, Log.DEBUG)) {Log.d(TAG, String.format("Entry %s", entry.getName()));}}}//内部静态类return new ParsedUpdate(file, payloadOffset, payloadSize, props);}
2.2.2. applyPayload请求升级
调用framework java应用层的接口
//frameworks/base/core/java/android/os/UpdateEngine.javaprivate IUpdateEngine mUpdateEngine;private IUpdateEngineCallback mUpdateEngineCallback = null;private final Object mUpdateEngineCallbackLock = new Object();public void applyPayload(String url, long offset, long size, String[] headerKeyValuePairs) {try {mUpdateEngine.applyPayload(url, offset, size, headerKeyValuePairs);} catch (RemoteException e) {throw e.rethrowFromSystemServer();}}
2.2.3. 序列图Permalink
3. 绑定回调流程
3.1. UpdateEngine.bind绑定
//packages/apps/Car/SystemUpdater/src/com/android/car/systemupdater/UpdateLayoutFragment.javaprivate ProgressBar mProgressBar; //升级进度private File mUpdateFile; //升级包文件private Button mSystemUpdateToolbarAction;//PowerManager对象，用于重启private PowerManager mPowerManager;private NotificationManager mNotificationManager;private final UpdateVerifier mPackageVerifier = new UpdateVerifier();//创建UpdateEngine对象private final UpdateEngine mUpdateEngine = new UpdateEngine();private boolean mInstallationInProgress = false;//新建对象private final CarUpdateEngineCallback mCarUpdateEngineCallback = new CarUpdateEngineCallback();...
//UpdateLayoutFragment.java的onPostExecute函数调用/** Show the install now button. */private void showInstallNow(UpdateParser.ParsedUpdate update) {mContentTitle.setText(R.string.install_ready);mContentInfo.append(getString(R.string.update_file_name, mUpdateFile.getName()));mContentInfo.append(System.getProperty("line.separator"));mContentInfo.append(getString(R.string.update_file_size));mContentInfo.append(Formatter.formatFileSize(getContext(), mUpdateFile.length()));mContentDetails.setText(null);//调用installUpdatemSystemUpdateToolbarAction.setOnClickListener(v -> installUpdate(update));...}/** Attempt to install the update that is copied to the device. */private void installUpdate(UpdateParser.ParsedUpdate parsedUpdate) {//调用showInstallationInProgressshowInstallationInProgress();//调用applyPayloadmUpdateEngine.applyPayload(parsedUpdate.mUrl, parsedUpdate.mOffset, parsedUpdate.mSize, parsedUpdate.mProps);}//绑定UpdateEngine，并且显示进度/** Set the layout to show installation progress. */private void showInstallationInProgress() {mInstallationInProgress = true;mProgressBar.setIndeterminate(false);mProgressBar.setVisibility(View.VISIBLE);mProgressBar.setMax(PERCENT_MAX);mSystemUpdateToolbarAction.setVisibility(View.GONE);showStatus(R.string.install_in_progress);//CarUpdateEngineCallback回调函数调用mUpdateEngine.bind(mCarUpdateEngineCallback, new Handler(getContext().getMainLooper()));}
3.2. onStatusUpdate和onPayloadApplicationComplete接口函数
- 升级状态码见
frameworks/base/core/java/android/os/UpdateEngine.java - UpdateStatusConstants（抽取system/update_engine/client_library/include/update_engine/update_status.h数据） - 升级错误码见
frameworks/base/core/java/android/os/UpdateEngine.java - ErrorCodeConstants（抽取system/update_engine/common/error_code.h部分）
//UpdateLayoutFragment.javapublic class CarUpdateEngineCallback extends UpdateEngineCallback {@Override//升级状态码和进度接收public void onStatusUpdate(int status, float percent) {if (Log.isLoggable(TAG, Log.DEBUG)) {Log.d(TAG, String.format("onStatusUpdate %d, Percent %.2f", status, percent));}switch (status) {//UpdateStatusConstants升级状态码见frameworks/base/core/java/android/os/UpdateEngine.javacase UpdateEngine.UpdateStatusConstants.UPDATED_NEED_REBOOT:rebootNow();break;case UpdateEngine.UpdateStatusConstants.DOWNLOADING:mProgressBar.setProgress((int) (percent * 100));break;default:// noop}}@Override//升级结果接收public void onPayloadApplicationComplete(int errorCode) {Log.w(TAG, String.format("onPayloadApplicationComplete %d", errorCode));mInstallationInProgress = false;//错误码见frameworks/base/core/java/android/os/UpdateEngine.java的ErrorCodeConstants集合定义showStatus(errorCode == UpdateEngine.ErrorCodeConstants.SUCCESS? R.string.install_success: R.string.install_failed);mProgressBar.setVisibility(View.GONE);mSystemUpdateToolbarAction.setVisibility(View.GONE);}}
重启接口调用：
private void rebootNow() {if (Log.isLoggable(TAG, Log.INFO)) {Log.i(TAG, "Rebooting Now.");}mPowerManager.reboot(REBOOT_REASON);}
3.3. 升级状态码解释
//frameworks/base/core/java/android/os/UpdateEngine.java/*** Status codes for update engine. Values must agree with the ones in* {@code system/update_engine/client_library/include/update_engine/update_status.h}.*/public static final class UpdateStatusConstants {//IDLE状态public static final int IDLE = 0;//update engine服务检查升级public static final int CHECKING_FOR_UPDATE = 1;//存在可获取的升级public static final int UPDATE_AVAILABLE = 2;//downloading下载步骤状态public static final int DOWNLOADING = 3;//update engine正在校验状态public static final int VERIFYING = 4;//update engine正在完成一个升级public static final int FINALIZING = 5;//请求重启（一般是升级成功）public static final int UPDATED_NEED_REBOOT = 6;//update egnine上报一个错误事件public static final int REPORTING_ERROR_EVENT = 7;//update engine试图恢复一个升级（可能升级被中断过）public static final int ATTEMPTING_ROLLBACK = 8;//update engine处于被禁止状态public static final int DISABLED = 9;}
3.4. 升级错误码解释
//frameworks/base/core/java/android/os/UpdateEngine.java/*** Error codes from update engine upon finishing a call to* {@link applyPayload}. Values will be passed via the callback function* {@link UpdateEngineCallback#onPayloadApplicationComplete}. Values must* agree with the ones in {@code system/update_engine/common/error_code.h}.*/public static final class ErrorCodeConstants {//升级成功public static final int SUCCESS = 0;//升级失败public static final int ERROR = 1;//文件系统拷贝失败public static final int FILESYSTEM_COPIER_ERROR = 4;/*** Error code: an update failed to apply due to an error in running* post-install hooks.*///post-install运行时报错public static final int POST_INSTALL_RUNNER_ERROR = 5;/*** Error code: an update failed to apply due to a mismatching payload.** <p>For example, the given payload uses a feature that's not* supported by the current update engine.*/public static final int PAYLOAD_MISMATCHED_TYPE_ERROR = 6;/*** Error code: an update failed to apply due to an error in opening* devices.*/public static final int INSTALL_DEVICE_OPEN_ERROR = 7;/*** Error code: an update failed to apply due to an error in opening* kernel device.*/public static final int KERNEL_DEVICE_OPEN_ERROR = 8;/*** Error code: an update failed to apply due to an error in fetching* the payload.** <p>For example, this could be a result of bad network connection* when streaming an update.*///download传输报错，比如U盘升级download时拔出U盘public static final int DOWNLOAD_TRANSFER_ERROR = 9;/*** Error code: an update failed to apply due to a mismatch in payload* hash.** <p>Update engine does sanity checks for the given payload and its* metadata.*/public static final int PAYLOAD_HASH_MISMATCH_ERROR = 10;/*** Error code: an update failed to apply due to a mismatch in payload* size.*/public static final int PAYLOAD_SIZE_MISMATCH_ERROR = 11;/*** Error code: an update failed to apply due to failing to verify* payload signatures.*/public static final int DOWNLOAD_PAYLOAD_VERIFICATION_ERROR = 12;/*** Error code: an update failed to apply due to a downgrade in payload* timestamp.** <p>The timestamp of a build is encoded into the payload, which will* be enforced during install to prevent downgrading a device.*///版本时间戳校验，如果不支持回滚，则回滚升级会报错public static final int PAYLOAD_TIMESTAMP_ERROR = 51;/*** Error code: an update has been applied successfully but the new slot* hasn't been set to active.** <p>It indicates a successful finish of calling {@link #applyPayload} with* {@code SWITCH_SLOT_ON_REBOOT=0}. See {@link #applyPayload}.*/public static final int UPDATED_BUT_NOT_ACTIVE = 52;}