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.java
1.2. 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 := disabled
LOCAL_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_appcompat
include $(BUILD_PACKAGE)
1.3. AndroidManifest.xml
<!-- 包名 -->
<manifest
xmlns: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 -->
<application
android:label="@string/title"
android:theme="@style/SystemUpdaterTheme">
<activity
android: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 AppCompatActivity
implements 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
};
@Override
protected 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newResumedInstance
UpdateLayoutFragment 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
@Override
public 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
@Override
public 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)
@Override
public 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> {
@Override
protected 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;
}
}
@Override
protected 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.java
static 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.java
private 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
3. 绑定回调流程
3.1. UpdateEngine.bind绑定
//packages/apps/Car/SystemUpdater/src/com/android/car/systemupdater/UpdateLayoutFragment.java
private 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installUpdate
mSystemUpdateToolbarAction.setOnClickListener(v -> installUpdate(update));
...
}
/** Attempt to install the update that is copied to the device. */
private void installUpdate(UpdateParser.ParsedUpdate parsedUpdate) {
//调用showInstallationInProgress
showInstallationInProgress();
//调用applyPayload
mUpdateEngine.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.java
public 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.java
case 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;
}
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